Test discs for testing and listening on high-quality equipment. Methodology for testing acoustic systems Testing an acoustic system

The price category of 3-4 thousand dollars is quite densely populated - here you can come across acoustic solutions that are very different from each other both from an ideological and design point of view. “Music-design” speakers, distinguished by their attractive appearance and high degree of integration into any interior (which sometimes leads to functional limitations), are adjacent to large and quite high-quality speakers. However, if you still adhere to strict hi-fi requirements, then according to a number of criteria, “micro-speakers” from respected audio brands are in the lead in this range. The price balance definitely works in favor of just such options. Within a rather limited budget, a manufacturer rarely manages to make solid floor-standing units, providing the necessary rigidity and damping for large-capacity cases. A small body requires less manufacturing effort and, accordingly, lower costs. And although there are pleasant exceptions (we will look at them in the test), the general rule of thumb is that in the specified price range, small floor-standing speakers are characterized by better quality cabinets, components and workmanship, are equipped with better speakers and, ultimately, provide a more reliable and exact sound for the same amount. Of course, the usual restrictions for small forms also do not disappear. Small woofers installed in narrow enclosures are most often not able to withstand significant input power for a long time; they have a very moderate lower bass limit and, in general, a much smaller sound than their more respectable counterparts. Whether musical expressiveness will suffer in this case largely depends on the specific company and design school. Compact, but well-tuned speakers have every chance to win over large ones, but not free from compromises in terms of quality. And, let’s say, in conditions of limited living space, the ability to create big sound will not be so in demand and even problematic from the point of view of obtaining accurate sound in a small room.

Test system

1. Source - CD player Bryston BCD-1
2. Integrated amplifier - Bryston B100 SST
3. Cables - Analysis Plus

Test records

1. G. Purcell, “King Arthur” (Harmonia Mundi, 195200)
2. Empire Brass Quintet and William Kuhlman, "Baroque Music for Brass and Organ" (Telarc, 80614)
3. N.A. Rimsky-Korsakov, Symphony No. 2 “Antar” (DG, 423 605-2)
4. Ludwig van Beethoven, Piano Sonata No. 23 in F minor “Appassionata” (DG, 457 296-2)
5. W. Baumgratz, “Organ Landscape” (MDG, 319 0962-2 MDG Gold)
6. Tory Amos “Little Earthquakes” (Atlantic, AT82358)
7. Blackmore’s Night “Beyond the Sunset” (SPV, 087-69900)
8. Rammstein “Mutter” (Motor Music, 549 639-2)
9. The Who "Quadrophenia" (MCA MCAD2-11463)
10. Helloween “The Keeper of the Seven Keys, Part 2” (Victor Ent. Japan, VICP-63364-5)
11. Dark Tranquility “Haven” (Century Media Rec., 77297-2)

Page 2 - Rega RS 7
Page 3 - Audio Physics Spark
Page 4 - KEF XQ30-AA
Page 5 - Heco Celan XT 901
Page 6 - PMC GB1i
Page 7 - System Audio Mantra 60
Page 8 - Results

Prices shown are indicative only.

Rega RS 7

Price - 90,000 rub.

From 1973 to the present day, Rega has been associated with its founder and permanent leader, Roy Gandhi, a passionate fan of vinyl and analogue sound. The change of lines and products of the company occurs in English conservatively - with the preservation of family values ​​and without revolutionary changes

The new RS model differs from its predecessor with the R index not so significantly. The main change (besides design improvements) is the use of a modified 19mm silk dome tweeter HF20-ZRR (Zero Rear Reflection - dampening the contribution of reflections of sound waves emitted by the rear side of the speaker) with an anti-resonance chamber. According to the manufacturer, this has significantly improved frequency response at high frequencies. The midrange driver has a 90 mm cellulose diaphragm, a phase-correcting body in the shape of a truncated cone and a rubber surround. A 15cm woofer made of the same material is placed on the side of the narrow but deep cabinet. Thanks to the design of the woofer and coil, which provides strong attenuation at mid frequencies, there is no separating filter between the low-frequency and mid-frequency bands at all, and the most minimalist one is used for the high-frequency driver.
All emitters have cast aluminum baskets and operate in a common chamber. The cabinets are covered with white piano varnish. The appearance of the acoustics is slightly spoiled by the huge rectangular hole on the side wall next to the woofer, which serves as a bass reflex port. However, it is not visible behind the protective grill.
The speakers are distinguished by a calm, smooth and slightly soft character, very coherent and with a slightly smoothed attack. This style is preserved when performing recordings of any genre and at any tempo (acoustics can play subjectively quickly, but without chaos and fragmentation), which sometimes is clearly beneficial, and sometimes, depending on the musical material, and vice versa. The situation is also affected by the somewhat limited bass depth, which remained despite numerous attempts to optimize the position of the speakers in the room. The softness of the low-frequency range, coupled with a general reduced response, sometimes led to a decrease in the expressiveness of the lower notes of the organ and piano and to the muted lines of the large orchestral drum. The speakers need additional heating, which was strongly recommended by the distributor's representatives. A few days of work in our laboratory conditions was clearly not enough for them.
From a soundstage point of view, loudspeakers always provide a large foreground in which vocalists or solo instruments stand out perfectly. In large multi-layered and multi-plane forms (BSO, choir, etc.), the backgrounds were not always drawn convincingly; sometimes in tutti they overflowed into the foreground, and the scene as a whole unfolded in depth in a moderate way. However, the overall presentation was melodious, comfortable and not at all loud; only occasionally (especially in dynamic peaks) could a slight hint of roughness be detected, for example, in high academic vocals, violin and brass instruments. In a number of tracks of an overly aggressive nature (modern metal), on the contrary, at times some softness appeared and a feeling of insufficiently free sound arose. Rega RS7 speakers deliberately avoid extremes and drama. At the same time, they show themselves at their best in non-academic vocals and ensemble music. In moderately fast recordings, the rhythm was maintained very well, and attack was practically absent, and therefore the impressions of classic old metal, rock and various pop music were the most positive.

Measurement results

The low-frequency driver and mid-frequency driver located on the side surface of the speaker body have a fairly extended zone of intersection of operating frequencies, in which they act together. Therefore, the bass level and uneven sensitivity at the interface between the bands will greatly depend on the position of the speakers - both in the room and relative to each other and the listener (Fig. 1). In general, the installation opens up prospects for creativity. Rega RS7 demonstrate the highest levels of unevenness in the amplitude-frequency response and the level of nonlinear distortion in the test. In the measured range from 100 Hz to 10 kHz, the average SOI value was 0.84%, and closer to the lower limit it exceeded the 2% barrier (Fig. 3). The behavior of the impedance module cannot be called stable, but the minimum does not fall below 4 Ohms, and the average value is 8.1 Ohms (Fig. 2).

Passport details:
Type - floor-standing speaker systems | Name - Rega RS7 | Frequency response, Hz - not specified | Number of bands - 2.5 (LF - 15 cm, paper, LF/MF - 10 cm, paper, HF - 1.9 cm, silk dome; crossover frequencies not indicated) | Acoustic design - bass reflex | Resistance, Ohm - 6 | Sensitivity, dB - 89 | Dimensions of one column, cm - 98.8 x 24.6 x 34.6 | Weight of one column, kg - 17

Ratings:
Design - 90%
Workmanship - 85%
Sound - 85%
Ergonomics - 90%

Final grade - 85%

pros: solid melodious sound, calm comfortable manner, large images of soloists
Minuses: slightly limited resolution, not the deepest bass

Conclusion:
Not too busy music “without drama” is played smoothly and musically, very rhythmically and quickly. Small compositions, rock, good old metal and various calm compositions are produced well and expressively by the speakers.

Audio Physics Spark

Price - 90,000 rub.

Manfred Diestertich, chief designer of the German Audio Physic, is known for his dislike of “wonderful modern materials” and his adherence to traditional paper speakers. Nevertheless, the reincarnation of the rather old Spark model carried out by him in 2005 turned out to be by no means conservatively vintage

Thin, tilted-back “Leaning Towers of Pisa” have bodies that are smoothly curved in cross-section and are approximately equal in depth and width. An inch soft dome with special impregnation ensures reproduction of high frequencies. Two identical midrange/bass drivers with 95-mm diffusers made of coated paper and concave-shaped protective caps are equipped - this is the company's know-how - with a double chassis: cast aluminum outer baskets and plastic inner ones. The drivers, called HHCM (Hyper-Holographic Cone Midrange), are driven by neodymium magnets and operate in a 2.5-way circuit. Small oval black grills cover only the upper part of the front panel with the speakers. Excellent quality dark maple veneer, which has retained the living wood texture, greatly enhances the appearance of the acoustics. The large round neck of the bass reflex port faces backwards, and underneath is a solid steel terminal block with one pair of rhodium-plated WBT terminals. The cross-shaped stands end with sharp steel spikes, which are adjustable from above and covered with round plastic pads.
Being placed straight, without turning towards the listener, the speakers demonstrated a very smooth and accurate sound, which I always wanted to characterize with the words “perfectly appropriate and proportionate.” A constant competitor to the RMS acoustics (they were almost on par for almost the entire test, beating each other by half a length in terms of subtle effects), this model definitely outperforms the British in microrhythmic nuances and surprisingly clear, almost graphic, melodic lines drawn in ink, although it lags a little behind in subtle details and fullness of instrument timbres. The sound signature is distinguished by impeccably integrated tones and noises that accompany sound production, so that neither the first nor the second is separated or dominant anywhere. In addition to outstanding rhythmicity, the speakers are characterized by excellent mastery of any musical material. Baroque sounded delicate and delicate, as if it was perfectly laid out in the smallest rhythmic beats and patterns, visible as if under a microscope. The same applied to the large orchestral form and to the choir (the diction of the choristers and vocalists was simply exemplary, even if you write a dictation). The only minor quibble concerns some lack of density in the timbres of the strings, and they could use a little more pressure. The dramatic roll of a large orchestral drum, with all its rise and fall, was also presented rhythmically ideally and in extreme detail, but I just wanted it to be thicker in timbre. But the HF resolution and detail in this frequency range exceed what RMS acoustics provide, as well as the ability to withstand the impact of dynamic peaks.
In all non-academic genres, including very extreme options, the speakers demonstrated a very free, problem-free and energetic sound with a fair amount of comfort (in a good sense, without imposing, overheated timbres or softness). There is no need to talk about the rhythm and its retention - this is the signature feature of the brand, in which it has few competitors.

Measurement results

The impedance modulus and electrical phase of the Audio Physics Spark speakers demonstrate excellent stability across the entire frequency range (Figure 2). The difference between the maximum (10.6 ohms) and minimum (4.2 ohms) resistance is slightly more than 6 ohms, and the average value is 6.2 ohms. Thanks to this, this speaker system will easily work with any amplifier. The amplitude-frequency response measured at the tweeter axis has a serious and unpleasant dip in the middle of the HF range (Fig. 1). But the picture is completely transformed and the unevenness indicator becomes commendably small, as soon as you turn the speaker away from the listener. The value of the nonlinear distortion coefficient is consistently low in most of the audio frequency range, increasing only at the lower limit (Fig. 3). The average THD value in the range from 100 Hz to 10 kHz is 0.4% at a sound pressure level of 88 dB.

Passport details:
Type - floor-standing speaker systems | Title - Audio Physic Spark | Frequency response, Hz - 38—33,000 (level not specified) | Number of bands - 2.5 (LF/MF - 2 x 15 cm, coated paper, HF - 2.5 cm, silk dome; crossover frequencies not indicated) | Acoustic design - bass reflex | Resistance, Ohm - 4 | Sensitivity, dB - 89 | Dimensions of one column, cm - 98 x 14.7 x 22 | Weight of one column, kg - 17

Ratings:
Design - 95%
Sound - 95%
Ergonomics - 90%

Final grade - 95%

Pros: excellent macro- and microdynamics, outstanding rhythmic resolution
Minuses: some natural timbres and voices could use more richness and fullness

Conclusion:
The speakers reproduce the finest rhythmic structures with the same perfect precision as Swiss chronometers. In addition, they have a fast, free flow that is as comfortable as it is emotional, and has outstanding genre versatility.

KEF XQ30-AA

Price - 132,400 rubles.

The English company KEF has several secrets of success. Among them are the Uni-Q point emitter with a coaxial arrangement of midrange and tweeter speakers, control magnets made of an alloy of neodymium, iron and boron, as well as experimental plastic diffusers, the development of which began almost half a century ago in collaboration with the BBC

The elegant narrow cabinets of the compact microfloor units do not have a single parallel wall; all their edges are smoothly curved. Inside, they are reinforced with ties, the location of which was optimized using computer modeling. The branded patented Uni-Q module in the new version has a Tangerine waveguide for high frequencies. It is argued that this ensures a smoother frequency response in the HF region and a smooth junction between the high-frequency and mid-frequency ranges. Two characteristic features of these speakers are borrowed from the top-end Reference series - an elliptical (rather than hemispherical) aluminum tweeter in cross-section and rather cool fourth-order filters that cross-link the high-frequency and mid-range ranges. The tweeter is mounted in the center of the plastic cone of the 130mm midrange driver, and the entire module is driven by a magnet made from a neodymium-iron-boron alloy. Low distortion and a wide power range are claimed for a similarly sized low-frequency driver. The two pairs of speaker terminals are equipped with jumpers made of wire rather than metal strips. The white piano lacquer finish goes well with the black brushed aluminum front panel, which has a nice moire pattern.
KEF XQ30-AA are another speakers that definitely prefer direct, no-turn, installation in the room. In this disposition, they demonstrate a homely and calm character, and listening to music becomes like long, leisurely conversations with good old friends, which later leave some kind of warm feeling. The classical music as a whole was played a little softly, sometimes muffled, sometimes a little more thoughtfully and less dramatically than necessary, but generally true, with the right timbres, beautiful voices, in a good mood and, as they say, in tune. The BSO was slightly lacking in scope and scale, however, taking this caveat into account, everything was presented very harmoniously and pleasantly. Audiophile characteristics, such as resolution in frequency subranges, transparency, holographicity, are not provocative, do not dominate or are not emphasized (with the exception of surprisingly subtle and simply magnificent in texture HF, which is simply impossible not to pay attention to). Objectively, in almost all genres there was a slight lack of sharpness and spontaneity, the angles and pressure were a little smoothed out, but the general sincerity and good mood for the positive, which mysteriously arose during listening, discouraged any desire to criticize the speakers over trifles.
The recordings of Tori Amos and Blackmore's Night sounded very airy, atmospheric, with simply crystal plucking of the strings and all the instrumental lines, softly but clearly written and perfectly audible. The acoustics played beautifully and comfortably, but at the same time true, emotional and energetic, when needed. All rock and old-school metal were performed quite well, sometimes a little intelligent and soft (the most killer tracks), but always rhythmic, exciting, not one gram hard or flat. This material showed commendable heaviness and weight, but lack the bass practically did not attract attention.

Measurement results

The unevenness of the amplitude-frequency response of the KEF XQ30-AA at medium frequencies and in most of the low-frequency range is extremely small (Fig. 1). The graph only occasionally and slightly falls outside the 3 dB corridor. However, a narrow but very deep dip in sensitivity at the beginning of the high-frequency range (due to the coaxial design of the speaker) leads to a deterioration in this indicator for high frequencies. The minimum resistance value lies around 140 Hz and is equal to 3.2 Ohms (Fig. 2). Although the nature of the load in this region is not purely resistive, such a value will not cause problems with the selection of the amplifier. The average THD value at a sound pressure level of 88 dBSPL is 0.39% (Fig. 3). The peak surge in the mid-frequency range, almost up to 2%, will most likely not appear when listening to musical compositions.

Passport details:
Type - floor-standing speaker systems | Name - KEF XQ30-AA | Frequency response, Hz - 48—55,000 (level ±3 dB) | Number of bands - 3 (LF - 13 cm, paper, MF/HF - Uni-Q coaxial speaker, 13 cm, polypropylene cone, HF - 1.9 cm, aluminum dome; crossover frequencies 450 and 2500 Hz) | Acoustic design - bass reflex | Resistance, Ohm - 8 (minimum 3.2) | Sensitivity, dB - 87 | Dimensions of one column, cm - 85.6 x 19 x 29.3 | Weight of one column, kg - 14.8

Ratings:
Design - 90%
Sound - 90%
Ergonomics - 95%

Final grade - 90%

Pros: precise rhythm, excellent highs, wide and deep stage, good headroom
Minuses: slight lack of bass

Conclusion:
Harmonious, beautiful externally and internally, the speakers are conducive to long-term comfortable listening to music of a wide variety of genres. Some lack of sound volume is compensated by excellent presentation - slightly soft, light and very soulful

Heco Celan XT 901

Price - 100,000 rubles.

The reputable German company Heco, with almost sixty years of history and rich traditions in the design of acoustic systems, recently presented a new model range for 2010-2011, calling it a landmark for itself. As usual with the company, innovation is combined with tradition, and quality with a reasonable price.

Massive speaker bodies in the form of hexagonal prisms are covered with walnut veneer. For strength, two ties are installed inside them. The high-frequency spectrum is reproduced by a traditional Heco fabric dome coated with nanoparticles (carbon-based particles 10-8 cm in size), providing strength and flexibility at the same time. The material of the diffusers for the midrange and bass speakers is the same and also typical for the company - kraft paper, made from a mixture of northern pine wood pulp and wool fibers (in a ratio of 95 to 5). The mid-frequency head is mounted on a coated fabric suspension and placed in a separate chamber in the upper part of the housing. Under the tweeter there are two identical low-frequency woofers on wide and soft rubber surrounds.
All speaker baskets are cast aluminum. The design is solid to the point of paranoia; the outer edges of the baskets, polished to a mirror shine, are tightly attached to the body with self-tapping screws. Two large round bass reflex ports, also made of cast aluminum, are directed towards the rear. Below them is a wide steel terminal plate with five distinct, widely spaced acoustic terminals: four of them are bi-wired, and the fifth is designed to increase HF output by +2 dB. The stand follows the shape of the body and ends with small rubber hemispherical legs.
In the classics, the model was noted for its weighty sound with some emphasis on the lower frequency range. However, this was done in a manner that excluded static or sluggishness. It’s just that the lower notes of cello, double bass, and piano (as well as drums in non-academic genres) became noticeably more tangible and acquired a deep velvety quality. Calm and transparent, like the heavy surface of a large lake, the sound pleased with its freedom and ideal rhythm. And instead of technical tempo, a living pulse, appropriateness and natural liveliness of musical events appeared.
The scene that caught my attention was wide and deep, unfolding according to the plans very freely and naturalistically, with excellent positioning of the sources. The midrange and high-frequency range at first seemed a little soft, as if in a slight haze, but the longer you listen to these acoustics, the more subtle details and timbral relationships and differences are revealed. Still, a small dip in the middle, which always leads to a desire to turn it up louder, is partly noticeable here too. But the speaker's power reserve is so impressive that this happens absolutely calmly, without the slightest harshness or loudness.
A separate tasty feature characteristic of the speakers is the development of after-sounds: with short intense tails, which, depending on the hall, instrument and recording, end in completely different ways. The same applies to the scattering of cymbals in non-academic music, so that the real quality of the high frequencies that initially seemed soft and smoky is simply amazing. In rock, metal, and pop numbers, the voices are so alive, and all the instruments are drawn so tangibly, large-scale, almost physically felt, that the effect of presence immediately arises.

Measurement results

Heco Celan XT 901 acoustic systems are leaders in a number of parameters, and not only weight and size. The speakers start operating at 23 Hz (at a level of -10 dB) and have a very significant margin of safety - the average SOI value in the region of medium and high sound frequencies (0.24%) does not undergo significant changes over a much larger range of input powers than that of opponents (Fig. 3). The fly in the ointment of these achievements comes from frequency fluctuations. The graph of the amplitude-frequency characteristic can be divided into 2 sections, each of which has enviable stability (Fig. 1). The separation between them occurs at the border of the mid and high frequency ranges and is accompanied by a noticeable decrease in sensitivity. Perhaps this decline will be partially leveled out with increasing distance from the listener to the speaker.

Passport details:
Type - floor-standing speaker systems | Name - Heco Celan XT 901 | Frequency response, Hz - 20—52,000 (level not specified) | Number of bands - 3 (LF - 2 x 20 cm, paper, MF - 17 cm, paper, HF - 2.5 cm fabric coated with nanoparticles; crossover frequencies 250 and 3400 Hz) | Acoustic design - bass reflex | Resistance, Ohm - 4—8 | Sensitivity, dB - 92 | Dimensions of one column, cm - 120.5 x 28.8 x 41.8 | Weight of one column, kg - 41

Ratings:
Design - 90%
Workmanship - 95%
Sound - 95%
Ergonomics - 90%

Final grade - 95%

Pros: fundamental bass, excellent resolution of highs and mids, excellent rhythm and stage
Minuses: academic vocals can sometimes be harsh

Conclusion:
Excellent all-round speakers that perform above their price. They are especially good at large-scale symphonic classics - in them they demonstrate a very large and serious sound, a luxurious multi-faceted stage and deep interesting timbres

PMC GB1i

Price - 100,000 rubles.

The next PMC model - the junior floor-standing speakers in the line of home speakers - is a miniature two-way speaker. As befits this English company, they are equipped with proprietary acoustic design - a four-section transmission line with an effective length of 2.4 m

These are the second emphatically miniature acoustic systems in the test after the KEF acoustics. The appearance and decoration of the cabinets are immediately recognizable and typical for RMC - just look at the traditional front panel, the rectangular output of the transmission line, which is covered with acoustic foam, and the standard terminal block at the back (the company promotes multiwiring, so the number of pairs of acoustic terminals always coincides with the number of working strips; in this case we have bi-wiring). The speakers are also already familiar to us from the PMC DB1i bookshelf model: this is a 27 mm soft fabric dome tweeter impregnated with SONOLEX™ (a joint development of PMC and SEAS, used throughout the entire line) and a fabric impregnated bass/midrange driver with a diameter of 140 mm on a cast alloy chassis and soft rubber suspension. The cabinets, finished in natural cherry veneer, rest stably on spiked legs protruding from the sides. Two-way micro-floor speakers look a little touching, but those who know this brand a priori have a fair amount of confidence in the design, and the design of the speakers is very nice.
Since the role of test acoustics in our editorial system is played by the floor-standing pair of RMCs, and in general representatives of the glorious English brand have repeatedly been guests of our magazine comparisons, the general character and sound style of the GB1i seemed more or less clear to us. In particular, we expected to hear accurate and fairly low bass with good texture (thanks to the acoustic design of the transmission line), well-balanced, full-fledged timbres and excellent rhythm. It was also assumed that these speaker systems would be among the leaders in sound quality. In general, this is how it all turned out. And although this time they had to compete for the palm with strong competitors, with whom it was difficult to compete in the jewelery rendering of rhythmic patterns and the clarity of drawing melodic lines, in a number of other indicators the British couple was still preferable. Firstly, of course, with its commendable timbres of natural instruments and voices, rich, but not overheated, in academic and non-academic genres. In baroque, refined compositions, the proportions of timbres and their interrelation seemed to be weighed down to the gram, with perfect balance. Needless to say about separating instruments that are close in height and other express checks for minor differences - RMS representatives always pass this test with extraordinary ease. The BSO seemed to be a slightly smaller copy of reality (the large form still turned out to be too small), but again all the proportions of the instruments lined up perfectly and in proportion, and the general mood and movement were very correct. Like an excellent microscope, the speakers pulled out an exceptionally large number of details and musical events from the general sound canvas, without losing musicality and fascination. And the emphasis was invariably on timbral variety and resolution. The voice delivery deserves special praise - it’s extremely soulful and meaningful, just right on point in terms of mood and conveying emotions.

Measurement results

The behavior of the graph of the impedance module of the PMC GB1 speaker systems allows us to characterize them as high-impedance (Fig. 2). The value of this parameter does not fall below 5.5 Ohms, the maximum is almost 41 Ohms, and the average value is 11.3 Ohms. The amplitude-frequency response with deviation from the radiation axis has a very stable course with a very slight increase in sensitivity in the upper bass; unevenness in the high-frequency (and partly mid-frequency) region is completely leveled by the rotation of the speakers (Fig. 1). The lower limit frequency at the level of -10 dB is 40 Hz. Nonlinear distortion is low over almost the entire audio frequency range, even at high input power levels (Fig. 3). In the range from 200 Hz to 10 kHz at a sound pressure level of 94 dBSPL, the nonlinear distortion coefficient does not exceed 0.5%, and its average value is 0.38%.

Passport details:
Type - floor-standing speaker systems | Name - PMC GB1i | Frequency response, Hz - 29—25,000 (level not specified) | Number of bands - 2 (LF/MF - 14 cm, impregnated fabric, HF - 2.7 cm, fabric; crossover frequency 2000 Hz) | Acoustic design - transmission line | Resistance, Ohm - 8 | Sensitivity, dB - 87 | Dimensions of one column, cm - 87 x 15.5 x 23.4 | Weight of one column, kg - 10.5

Ratings:
Design - 90%
Workmanship - 90%
Sound - 90%
Ergonomics - 95%

Final grade - 90%

Pros: exceptional information content and timbre detail, natural sound, excellent rhythm
Minuses: overload capacity was slightly less than expected

Conclusion:
Excellent speakers with the expected high sound level, once again confirming the status of the company. Musicality, timbral richness and expressiveness are beyond praise. Although some of the usual restrictions for a two-way system are still present

System Audio Mantra 60

Price - 90,000 rub.

Dane Ole Witthöft's mantra, which he has been repeating for over 25 years, is, of course, fast sound, produced by a multitude of identical, super-light, long-throw drivers, and precisely calculated and modeled narrow cabinets. You will always find both of these features in any System Audio product.

Rigid, narrow, but deep bodies inside are divided into sections by seven partitions, five of which are through, placed horizontally between the bass drivers, and two are blind, forming closed chambers at the top and bottom. The upper one is intended for the tweeter and midrange speaker, and the lower one, with a volume of 3 liters, is for filling with sand.
The soft dome of the tweeter, according to the company's engineers, is characterized by a wide radiation pattern (XS, or increased sound propagation surface). Five identical 11cm woofers have 12mm travel, two voice coils each and cast aluminum baskets. The weight of the paper membranes is only 0.8 g. The letters XL in the marking of the W1108XL speakers, in accordance with the manufacturer’s idea, mean “increased sound size.” One of these drivers works as a midrange driver, and the remaining four are responsible for the low-frequency spectrum. The working bands of the emitters are separated by the simplest audiophile crossovers.
The parallelepipeds of the cases are finished with a very beautiful, smooth and silky to the touch cherry veneer with light transverse striping. At the rear there is a large bass reflex port and one pair of excellent gold-plated terminals mounted directly into the slot of the stand.
The concept of fast sound achieved by using several small and lightweight long-throw woofers, for all its advantages, also has obvious expected disadvantages. In particular, the speakers clearly avoid busy music, large symphonic works and extreme modern genres. At the same time, there is no feeling of compression, the volume scale in dynamic peaks is not compressed, and the level of distortion is, in principle, at a low level. However, the sound lacks scale, richness and depth (at the extreme - weight, detail and pressure). BSO plays too easily and superficially, turning into formality, the tense dramatic vocals are boring, the piano is too smooth, although it sounds at an accelerated, cheerful tempo and very good rhythmically. Of the academic genres, columns do well in Baroque - it is presented gracefully, quickly, easily, and a little fragilely. Sometimes I wanted the performance to be sharper and a little brighter, but overall this presentation can be considered successful.
As far as we could understand, the optimal genres for these acoustics are rock, jazz, blues and other popular things. It is to them that the manufacturer’s “mantra” is fully applicable - to bring your favorite musician as close as possible to the listener, to literally bring him into the room. The distinctly pop-club style offers not the feeling of a large concert hall, but rather the intimacy of a club, large musical images at close range, a small well-lit stage, an almost physical feeling of contact with the performer. Here everything is oriented and focused on the voice or solo instrument with a slightly muted accompaniment in the background. This acoustics should certainly appeal to fans of non-academic small groups and pleasant relaxation after a hard day at work.

Measurement results

The SA Mantra 60's four identical bass drivers push the bottom end to a respectable (for speakers of this size) 44 Hz. Their working area, with a smooth and slight decrease in sensitivity, extends to the mid-frequency range up to the middle (Fig. 1). This is followed by an area of ​​high stability of the characteristic provided by one mid-range speaker. In the middle of the high-frequency range, a tweeter is connected and the sensitivity begins to increase. Optimal sound with a minimum of frequency fluctuations is achieved by turning the speakers away from the listener. The SA Mantra 60 exhibit low harmonic distortion (average 0.38%; Fig. 3) and a very stable impedance modulus curve (Fig. 2). The average resistance is 8 ohms, the minimum is 4.3 ohms. The measured sensitivity of the speakers gives a moderate value of 87 dB / 1 m. 1 W.

Passport details:
Type - floor-standing speaker systems | Name - System Audio Mantra 60 | Frequency response, Hz - 40—35,000 (level ±1.5 dB) | Number of bands - 3 (LF - 4 x 11 cm, paper, MF - 11 cm, paper, HF - 3 cm, silk dome; crossover frequencies not indicated) | Acoustic design - bass reflex | Resistance, Ohm - 8 | Sensitivity, dB - not specified | Dimensions of one column, cm - 113 x 14.5 x 27.5 | Weight of one column, kg - 22

Ratings:
Design - 90%
Workmanship - 90%
Sound - 85%
Ergonomics - 95%

Final grade - 90%

Pros: good tempo, textured foreground, expressive non-academic vocals
Minuses: not the highest timbral resolution, BSO lacks intelligibility of instrumental lines

Conclusion:
Relax class speakers, they love close-ups, club presentation in close contact between the performer and the listener, and effective emphasis on the voice or solo instrument. Dramatic multi-layered orchestral form or hard modern metal are not their thing

Results

First, I would like to note a couple of interesting points related to the measurement results. Firstly, the majority of test participants demonstrated optimal sound and a more even frequency response when they stood in the room without facing the listener, with a rotation of 30-40 degrees from the radiation axis. One gets the impression that the manufacturers deliberately tuned the acoustics, assuming direct installation. Secondly, almost all competitors (except Heco Celan XT 901) have very limited lower bass, modest even by shelf standards. The lower limit of 60-70 Hz at a level of -3 dB is an inevitable harsh price to pay for being super compact and undemanding in terms of room size. The results of the sound examination look like this.
Heco Celan XT 901, the largest and most serious speakers in design, was noted for the largest and largest sound. Strictly speaking, it is not entirely correct to compare them with microfloor units, which are mainly presented in the test.
On the other hand, if some company (and in the introduction it was mentioned that there are pleasant exceptions) considers itself capable of making much less compromise speakers with a decent sound for the same amount, then why not compare. We vote with our wallets. The German pair's weighty and physical, yet transparent and lively sound, naturally pulsating rhythm and excellent timbres are certainly worthy of the Best Buy title. Although all potential buyers should keep in mind that these speakers need a fairly spacious room for installation (a requirement that is completely irrelevant for the rest of the test participants).
All the way, two models - the Danish Audio Physics Spark and the English PMC GB1i - competed for who would get second place and the Hi-Fi Recommended award, ahead of each other in various parameters by literally the slightest. When performing classical music, the situation reached the point where the only way to make the final choice was to flip a coin. The Danes were filigree precise and rhythmically proportionate, showing ideal diction and tempo. But the British demonstrated better timbral resolution and overall sound density. Some instruments turned out to be more interesting with one pair or the other. For example, the needle-like pauses in the “Appassionata”, cutting through the flesh of the music like silver threads, and the light diamond passages of the piano clearly spoke in favor of the Danish couple. But vocals, especially female ones, and string timbres were preferred by the British. This status quo was only broken by listening to rock and metal, when the RMC speakers turned out to be somewhat harsh and produced an unexpectedly flat and tiring sound. But Audio Physics Spark performed here in all their glory - freely, comfortably and perfectly clear. And they ultimately deserved second place.
The second English pair of the test - also compact micro floorstanders KEF XQ30-AA - demonstrated an exceptionally cozy, homely and calm sound, which, however, acquired a fair amount of weight and iron muscles in expressive and aggressive genres, but without losing comfort. Separately, it is necessary to highlight the extraordinary overload capacity of these babies and the clean, crisp forte without compression. The harmonious balance of advantages and inevitable, but very well-executed limitations is worthy of the title of Editor's Choice. System Audio Mantra 60 was noted for its fast, smooth sound, love and extremely effective reproduction of music of popular styles. Nice design and excellent veneer of the cases are another plus. Among the disadvantages is the speakers’ rejection of complex multi-faceted multi-instrumental recordings, in which the collapse of the stage, crumpling and creeping of shots on top of each other, and loss of intelligibility and detail become too noticeable. Club-intimate presentation is the true strength of this acoustics.
Rega RS7, in accordance with the usual concept of its creator Roy Gandhi, showed a cohesive and rather agile sound, although not distinguished by high frequency resolution or outstanding microdynamics. It is hardly possible to examine the sound in detail with these speakers.
Among other things, they have a very small power reserve; in dynamic peaks, the volume scale is greatly compressed and loses many gradations, and with increasing volume, the distortion limit quickly comes. However, lovers of positive sunny music and calm presentation, who do not have spacious premises, may find this option suitable for themselves. The new model fully retains Reg's signature smoothness and melodiousness.

Maria Savina

Based on materials: hi-fi.ru

Let's imagine a person who is interested in music, but has never paid attention to sound quality. And so, having heard a lot about Hi-Fi and High-End technology, he decides to check for himself what “real sound” is. As a rule, he doesn’t have much money, and it’s a pity to spend it on what he doesn’t yet know. Our test of bookshelf speakers will be very useful for just such a person, and it is in this price range that you can find speakers that can demonstrate true Hi-Fi sound quality. Yes, you will have to make a small allowance for the bass depth. But, on the other hand, bookshelf acoustics, as a rule, play better at low volumes than floor-standing ones, and it will be easier to place them in the room. A dozen speakers - a wide choice. I am sure that among them there will be very, very worthy specimens.

Criteria for evaluation

We are dealing with classic workhorses, and the approach to testing is quite traditional. The frequency response and SOI will show us how flawlessly the speaker design is made from a technical point of view. Together with the design features of the model, this will constitute a design assessment.
Listening will make its own adjustments and will reveal the sound character of the speakers. Good bass depth and high quality are rarely combined in the bookshelf format, so we won’t be too strict about this parameter. But having a clean and even upper register is quite possible for small speakers. The importance of this parameter is extremely important for the natural presentation of musical material. High-quality sound at low volumes is also important and is an indicator of smooth, almost linear speaker dynamics. Timbral fidelity will allow you to enjoy the full beauty of the sound of each individual instrument. After all, musical instruments are created in order to enjoy their sound, and not to try to understand what exactly is playing. All this will add up to a sound rating. The last assessment is inversely proportional to the price: higher the price - lower the assessment.

Acoustic Energy 301

When developing the 300 series, the designers achieved visual minimalism. All small details such as screws and grill mounts are excluded from the appearance. The front wall of the speaker is finished with a black rubber-like coating that matches the color of the driver diffusers. The finishing of the speakers is also minimalistic - black or white varnish. Model 301 houses a proprietary 28 mm fabric dome tweeter and a traditional, well-recognized midrange/bass driver with a cone made of bent, heavily anodized aluminum with a diameter of 110 mm. This speaker is a distant legacy of the legendary AE1 monitors.

It is curious that the company decided to use a slotted bass reflex port located on the front panel. It was possible to save the size of the column while placing it conveniently near the wall.

Sound
The absence of any noticeable sound color allows the speaker to unfold and, even when playing rather restrainedly, present musical compositions in an interesting way. The smallest details are clearly visible, and the timbres are very close to natural. The entire frequency scale is well balanced both in level and dynamics - the sound is holistic.

Upper register intelligibility is not bad, but it is a little lacking for an open sound with enough air. On complex compositions, the intelligibility of musical material decreases. At low volumes the sound character remains almost unchanged.

Measurements

The frequency response is very smooth. The decline in the low-frequency region is uniform. Bass is medium deep. The THD is quite low right down to the very bottom and is practically independent of the volume level. Impedance is unstable.

Bowers & Wilkins 685

Sound: 4

Construction: 5

Price: 5

Advantages:

- Spacious sound

- Fast bass

Flaws:

- Slight simplification of timbres

The model represents the junior line of Bowers & Wilkins. Possessing a laconic modern design, the line nevertheless inherited some technologies from the flagships themselves. Of course, this only applies to inexpensive and effective solutions such as Nautilus tweeter tubes, Kevlar cones and a golf ball bass reflex port. The aluminum dome tweeter is surrounded by a special material that helps achieve spacious sound. The midrange/woofer uses a static bullet to smooth out the response at the upper end of frequencies.

The crossover of the model is minimized as much as possible - it is of the first order. The speaker body is finished with film, and the front panel is covered with a velvety material that is pleasant to the touch.

Sound
The sound of the model is open and bright. Detail is at a good level. The bass is collected and fast. Localization is clear. Impressive dynamic range.

Instrument timbres are slightly simplified at mid frequencies. In this case, the upper register region is very active.

It adds airiness and spaciousness to the sound. The model is characterized by increased emotionality and expressiveness.

Measurements

There are noticeable irregularities in the region of 2.5 kHz and 6-7 kHz, which disappear when the speaker is rotated 30°. However, the frequency balance shifts slightly to the low-frequency region. SOI is extremely low. The impedance is extremely unstable.

Canton Chrono 503.2

Sound: 4

Construction: 5

Price: 5

Advantages:

- Clean upper case

- Accurate reproduction of timbres

Flaws:

- Bass is weak at low volumes

Chrono 503.2 is a real German speaker: excellent workmanship, 100% quality control of each copy, Made in Germany. Despite the stated glossy finish, the speaker is covered with film, and only the front panel is made glossy. The size of the speaker is not very large, but the speaker managed to accommodate an impressive 180 mm. Of course, it is equipped with the traditional Canton aluminum diffuser. The suspension is made in the shape of a wave for the most linear and long piston stroke of the diffuser. The 25mm tweeter dome is made from a very lightweight but durable aluminum and magnesium alloy. For reliability, it is protected by a metal grill. There are two threaded holes on the bottom for mounting on a stand or bracket.

Sound
The musical material is presented very carefully. The frequency balance is almost perfect. The timbres of instruments are transmitted with high reliability, and small details are not lost sight of. There is no increased emotionality, but thanks to a wide and smooth dynamic range, the speakers manage to accurately convey the musical idea of ​​the composition. The bass is collected, neat, exactly in its place. However, it is not very deep, and at low volumes it loses its position even more. At first it seems that there are too many high frequencies, but they appear exactly when you really need them, and in the right quantities. The upper register is very clean, which fans of modern electronic music will certainly appreciate.

Measurements

The frequency response is smooth, although it depends quite strongly on the listening angle - the directivity of the speakers is relatively narrow. The THD is very low and there is good headroom at low frequencies. Impedance is unstable.

Chario Syntar 516

Sound: 3

Construction: 4

Price: 4

Advantages:

- Emotional presentation

- Clear localization

Flaws:

- Simplification of timbres

The Italian speaker is made in the most classic design with veneer finishing. Before sawing out the walls of the body, HDF slabs are finished on both sides with natural wood. This makes the speaker more durable. The assembly and further processing of the case is carried out manually by specialists in Italy. Finished specimens are carefully tested to ensure compliance with the required acoustic parameters. The Silversoft Neodium model's tweeter uses a special membrane coated with aluminum powder, just like in the company's top-line speakers. It is interesting that a significant part of the mid-range is also devoted to the tweeter - starting from 1 kHz. The shape of the midrange/bass speaker diffuser, double curved, was selected by the designers specifically taking into account psychoacoustics and over the course of months of research.

The bass reflex port ends in a simple hole cut asymmetrically into the bottom. High rubber feet on the bottom of the case allow the port to work quite efficiently.

Sound
The sound of the speakers is, on the one hand, soft and unhurried, and on the other, a very clear, active upper register. The timbre picture is slightly blurred, the smallest details are veiled. And yet the speakers manage to quite accurately and emotionally convey the mood of musical compositions. The bass is quite deep and slightly dominant in the overall sound picture. With good localization, the music scene lacks clarity and transparency. This is more noticeable on complex compositions. At low volumes the bass weakens, but the sound remains quite dynamic and emotional.

Measurements

The best frequency response is observed at a listening angle of 30°. The unevenness is relatively good, with an even roll-off in the low frequencies. SOI is quite good down to the lowest frequencies. The impedance is relatively stable.

Dynaudio DM 2/7

Sound: 5

Construction: 5

Price: 5

Advantages:

- Timbral fidelity

- Clean upper case

Flaws:

- Strictness in presentation

The DM line is the entry-level acoustics in terms of the famous Danish company Dynaudio. The column is designed in a completely recognizable style of this company. The gray front panel is specially made thicker to effectively dampen chassis resonances. The body itself is also carefully sealed and finished with high quality traditional veneer. The branded tweeter is equipped with a 28 mm dome made of textile impregnated with a special compound. The diffuser of the midrange/woofer speaker is stamped from the already well-proven magnesium silicate polymer. The driver voice coils are wound on a Kapton base with lightweight aluminum wire. Together with powerful magnetic systems, this allows for remarkable dynamics and sensitivity.

Particular attention is paid to maximum impedance linearity to minimize speaker dependence on the amplifier.

Sound
The presentation of musical material by the speaker is relaxed and natural. Excellent tonal resolution makes the sound stage very believable. The spatial placement of instruments is clearly visible.

The bass is tight and well-developed. The upper register is clear and pleasant to the ear. The sound is highly detailed and lacks coloration. At low volumes the speakers play just as confidently as at high volumes.

Measurements

The frequency response is elongated into a very even strip with a barely noticeable skew towards high frequencies. The focus is broad. THD is low and stable. The impedance is quite stable. Exemplary results.

Magnat Quantum 753

Sound: 5

Construction: 4

Price: 4

Advantages:

- Timbral accuracy

- Clean music scene

Flaws:

- Slightly sparse sound

The speaker from Magnat's mid-priced Quantum 750 line looks solid. The front wall is made thick (40 mm) to radically combat body resonances. A solid 30 mm thick podium also emphasizes the solidity of the structure. It is curious that the front panel and podium are polished to a shine, while the rest of the surface of the case is matte. The F-max tweeter is equipped with a dome made of a double textile compound and has an extended operating frequency range. The midrange/bass speaker diffuser is made of ceramic/aluminium. The voice coil is well ventilated. The aluminum speaker basket design is optimized for optimal airflow and reduced resonances.

The bass reflex port with a large horn is located on the rear wall. The crossover is optimized for signal phase and amplitude and is assembled from selected high-quality elements.

Sound
The speakers play emotionally, dynamically, quickly. At the same time, the timbres of instruments are perfectly conveyed, and the musical scene is not obscured by extraneous sounds - they are pure and deep. Sound source localization is excellent. The detailing is also at a high level.

The HF level is enough for an open sound with the presence of airiness, and at the same time the upper register is very neat and unobtrusive.

Bass of medium depth, collected and fast. There is a little lack of physicality and density of presentation. At low volumes, the enthusiasm of the speakers is lost, the emotionality fades.

Measurements

The unevenness of the frequency response is minimal, but the frequency imbalance towards the HF is obvious. The SOI varies within 1% and noticeably depends on the volume, but no obvious resonances are noted. Good SOI margin at low frequencies. Impedance is unstable.

Martin Logan Motion 15

Sound: 4

Construction: 4

Price: 3

Advantages:

- Energetic delivery

- Fast and tight bass

Flaws:

- Weak at low volumes

The speakers are eye-catching with their stunning natural finish and attractive black steel grille. The housing cover is slightly tilted back. There is another surprise under the grille - a ribbon tweeter (a sign of an expensive device). The front panel of the speaker is made of black anodized aluminum. The diffuser of the long-throw midrange/woofer speaker is also made of black anodized aluminum to match the panel. The emitters are matched through a crossover with an improved topology, assembled using polypropylene capacitors and low-loss electrolytes, as well as hand-wound inductors.

The circuit provides thermal and current protection. The bass reflex port is located on the rear wall. The speaker body is assembled from 19 mm thick MDF boards.

Sound
The peculiarity of the speakers is that they do not like to play at low and medium volumes. In this mode of operation, only the midrange remains of the frequency range, and the dynamics become inexpressive.

As the volume increases, fast, elastic bass and fairly detailed highs appear. However, the lower middle still continues to prevail. The presentation of the musical material is scathing. At the same time, we must pay tribute, no extraneous overtones are felt; on the contrary, after-sounds sometimes disappear even where they should be.

The model tends to simplify the instrument timbres a little. At the same time, the ribbon tweeter is very audible, which gives a characteristic delicate color to the mid-high range.

Measurements

Uneven frequency response in the HF region is noticeable. The decrease in sensitivity towards the low frequencies is quite sharp. The focus is broad. The SOI has slight rises in the midrange, but nevertheless remains below 1%. The impedance is relatively stable.

MK Sound LCR 750

Sound: 5

Construction: 5

Price: 4

Advantages:

- Focused sound

- Good tonal resolution

Flaws:

- Do not hide the shortcomings of the recording

All acoustic systems of the American company M&K Sound are made in black without any embellishment. And the main decoration of the products is compliance with the highest standards of sound reproduction. Series 750 is a compact set of speakers for creating a home theater. And the largest speaker in the series (not counting the subwoofer) is the 750 LCR model. The speaker is quite unusual, especially in our test. Firstly, the closed acoustic design reduces bass response. Secondly, the use of two midrange/woofer speakers at once significantly expands the dynamic range of the speaker. Third, the tweeter panel being rotated 4.7° away from the listener likely increases and/or equalizes the dispersion of various frequencies. The tweeter dome is made of silk coated with polymer.

The speaker diffusers are polypropylene, with mineral filler. Of particular note is the Phase-Focused crossover, which significantly improves almost all speaker parameters. The back wall has many threaded holes for different speaker mounting options.

Sound
Excellent control of musical material. The sound is almost monitor-like, smooth. All instruments are clearly visible: they are clearly defined both spatially and timbre. Nothing unnecessary interferes with the overall musical picture; all the nuances are heard clearly. And since there is no emotional coloring, the sound of the speakers is not as exciting as many other models, and depends entirely on the musical composition itself.

Measurements

Irregularities in the frequency response of the column are insignificant. A rotation of 30° gives the best results. The THD is very low and increases very smoothly towards low frequencies, exceeding 5% only at low volumes. The impedance is quite stable. Very worthy results.

PSB Imagine B

Sound: 5

Construction: 5

Price: 3

Advantages:

- Natural transmission of timbres

- Smooth dynamics

Flaws:

- HF area limited

The Canadian company PSB has been offering the Imagine line for several years. During this time, she managed to earn a Red Dot award for design and a lot of positive reviews from various experts. The column body is a geometric intersection of several elliptical cylinders. All walls are curved. And this creates a feeling of solidity and strength of the structure. The 25 mm tweeter also looks solid - a dome made of durable titanium, the coil is cooled by magnetic fluid, and a powerful neodymium magnet. The midrange/bass speaker diffuser is made of polypropylene with clay-ceramic filler (mineral). The bass reflex port is located on the rear side. The column is finished with high quality natural veneer.

Sound
The sound is collected and well balanced in frequency. Excellent localization and natural transmission of timbres make the musical scene almost real, alive. Smooth dynamics allow the speakers to play naturally and freely even at low volumes. Musical matter is pure. The high-frequency range is slightly limited, due to which the airiness is partially lost, turning into intimacy.

Speakers can miss the smallest details, but at the same time maintain expressiveness and richness of sound. The bass, although not deep, is very well designed. The mid frequencies are also quite good, timbre rich and quite correct.

Measurements

A very flat frequency response measured along the acoustic axis. Turning the speakers away from the listener is undesirable - they begin to lose treble frequencies. SOI is stable and low down to the lower frequency limit. Impedance is stable.

Rega RS1

Sound: 5

Construction: 4

Price: 4

Advantages:

- Clean upper case

- Wide dynamic range

Flaws:

- Slight coloration of sound

The English company Rega has developed and offers customers the only series of RS speakers. The purpose of their creation is to harmoniously complement other sound equipment also developed within the walls of Rega. However, speakers are available to buyers separately from this equipment. The RS1 model is quite compact and, judging by its weight, is assembled from thin MDF. Despite this, the performance of the speakers is top notch, with neat veneer finishing and a strict design. The drivers are designed by Rega engineers and hand-assembled in-house. The 19mm tweeter features a specially shaped rear chamber to better dampen sound waves from the back of the tweeter dome. Mid/bass speaker with paper diffuser.

The smooth frequency response of the speaker makes it easy to integrate it with a tweeter using a simple crossover with good phase locking. The bass reflex port is located on the rear wall.

Sound
The speakers reproduce timbres quite accurately, but due to the slight coloration, the music scene becomes a little less transparent. The upper register is missing quite a bit, but it is very clean. The details are present, but slightly veiled. Musical material is presented in a sweeping, open manner

The bass is quite accurate, but sometimes lacks weight. The localization of sound sources is somewhat blurred.

The speaker handles complex music somewhat worse - the intelligibility of the sound material decreases. However, at low volumes the speakers play very convincingly.

Measurements

Irregularities in the frequency response in the upper middle and high frequencies form the special character of the sound of the speakers. The speakers play more smoothly if they are rotated 30°. The SOI is unstable, but quite low, less than 1%. The impedance is extremely unstable.

Triangle Color Bookshelf

Sound: 5

Construction: 4

Price: 5

Advantages:

- Open live sound

- Accurate reproduction of timbres

Flaws:

- Slight excess bass

Very nice-looking speakers from the French manufacturer Triangle are available in three varnish colors - white, black and red. The Color line stands out with its bright, cheerful style among all Triangle products and takes its place as the entry-level line.

The bookshelf model uses a tweeter with a titanium membrane and a midrange/woofer with a paper cone. In general, the speaker is quite interesting; its suspension is wide, corrugated and basically made of fabric. The paper diffuser is coated with a special compound. The dust cap is designed in the shape of a bullet. The design of the crossover uses developments from the top Magellan line. The bass reflex port is located on the rear wall of the speaker.

Sound
The sound of the model is very lively and natural. Timbre fidelity is very high. The presentation of sound material is natural and relaxed.

The dynamics amazingly accurately replicate a live performance. The bass is deep and beautifully defined. Sometimes it even seems like there is too much of it.

The musical matter is very pure and extremely detailed. No nuances escape the speakers' field of view.

They cope with compositions of any complexity. The sound quality is not lost even at low volumes.

Measurements

The imbalance of the frequency response towards the HF is obvious. It is treated as usual - turning the AC by 30°. The SOI is quite low, although in the midrange it is noticeably higher, but remains within 1%. High volume causes slightly more distortion in the upper bass. Impedance is unstable.

Wharfedale Jade 3

Sound: 5

Construction: 5

Price: 4

Advantages:

- Good detail

- Clear localization

Flaws:

- Slightly weakened dynamics

The British company Wharfedale traditionally spares neither effort nor materials even on budget lines. And the Jade 3 model once again confirms this. In our test, this is the largest and heaviest shelf speaker, and the only 3-way one. A body with curved walls is a feature of the top lines of many other manufacturers, but not Wharfedale. Both the body shape and the additional bulkheads make the body as acoustically inert as possible, preventing unwanted sound coloration. High frequencies are handled by an aluminum dome tweeter. At the border of 3 kHz it is replaced by a midrange speaker with a diffuser made of aluminum-cellulose composite. And already in the region of 350 Hz, the initiative is seized by the woofer, equipped with a woven diffuser made of a mixture of carbon and fiberglass. The combination of such materials with a braided structure brings the diffuser closer to an ideal piston, eliminating the problematic resonance phenomena inherent in metal diffusers.

The speakers operate in a closed volume. The crossover for the speaker was optimized on a computer for maximum linearity of signal phase transmission.

Sound
Wharfedale speakers sound traditionally beautiful. All instruments are clearly arranged spatially. The music stage is clean and spacious.

The speakers deliver bass carefully, not forcefully, as if they are afraid of damaging the balance of the overall sound picture. The same can be said about upper case.

The softness of the presentation of musical material is interestingly and harmoniously combined with excellent sound detail. In addition, the speakers play very well at low volumes.

Measurements

The frequency response of the model is flat, but at high frequencies it behaves peculiarly - a decline and a sharp rise. The bass is deep. The SOI is almost perfectly flat and extremely low. Very solid headroom for low frequencies. The impedance is quite stable.

conclusions

It should be noted that it is becoming less and less interesting to study the results of speaker measurements in our test laboratory. Almost all models showed a remarkably flat frequency response and a very low THD even in the bass region! This is explained by the fact that almost all companies have already adopted computer modeling tools, with the help of which you can make, perhaps, anything sound, which, for example, the company Boston Acoustics has proven to us more than once. Even the shape of the body no longer plays such a significant role; the main thing is to correctly calculate the damping elements. Therefore, the design ratings for all models are either good or excellent.

Two models from our test deserve special mention. These are MK Sound LCR 750 and Dynaudio DM 2/7. The companies that created them were initially focused on developing professional acoustics and pursue this line even in their youngest lines. The main principle is maximum accuracy in transmitting musical material. And no decorations. These two models fully meet this principle and, in fact, represent professional-level monitor acoustics, with all its advantages and disadvantages. Not all listeners may like the sound, or more precisely, the neutrality of the sound. This is a product for special music connoisseurs and connoisseurs, or even for a home studio. Both models are worthy of the sympathy prize.

Almost all companies have already adopted computer modeling tools, with the help of which you can make, perhaps, anything sound.

If we talk about beautiful and comfortable sound, then many of the speakers in our test successfully coped with this task. Accurate transmission of timbres, precise localization, accurate bass - all this is inherent in almost all speakers tested. The only difference is in the nature of the sound. And here the choice turned out to be rich: in the test you can find a dense, rich sound (PSB Imagine B), and an impressively sophisticated sound (Wharfedale Jade 3), and a collected, neat presentation of material (Canton Chrono 503.2), and an open airy image (Rega RS1, B&W 685), and even defiantly aggressive pressure (Martin Logan Motion 15). However, most of all I would like to highlight the French columns Triangle Color Bookshelf. They turn almost any musical material into a celebration of sound. The speakers know how to not miss the main idea of ​​the work and at the same time present the material very beautifully, lively and dynamically. They are very pleasant and interesting to listen to. The Triangle Color Bookshelf model takes the title of test winner.

We continue our tradition and publish another article in the “testing methods” series. Articles such as these serve as both a general theoretical framework to help readers gain an introduction to the topic, and specific guidance for interpreting test results obtained in our laboratory. Today's article on the methodology will be somewhat unusual - we decided to devote a significant part of it to the theory of sound and acoustic systems. Why is this necessary? The fact is that sound and acoustics are practically the most complex of all the topics covered by our resource. And, perhaps, the average reader is less savvy in this area than, say, in assessing the overclocking potential of various Core 2 Duo steppings. We hope that the reference materials that formed the basis of the article, as well as a direct description of the measurement and testing methodology, will help fill some gaps in the knowledge of all lovers of good sound. So, let's start with the basic terms and concepts that any novice audiophile must know.

Basic terms and concepts

A short introduction to music

Let's start in an original way: from the beginning. From what sounds through the speakers, and about other headphones. It just so happens that the average human ear can distinguish signals in the range from 20 to 20,000 Hz (or 20 kHz). This fairly substantial range, in turn, is usually divided into 10 octaves(can be divided by any other quantity, but 10 is accepted).

In general octave is a frequency range whose boundaries are calculated by doubling or halving the frequency. The lower limit of the next octave is obtained by doubling the lower limit of the previous octave. Anyone familiar with Boolean algebra will find this series strangely familiar. Powers of two with an added zero at the end in their pure form. Actually, why do you need knowledge of octaves? It is necessary in order to stop the confusion about what should be called lower, middle or some other bass and the like. The generally accepted set of octaves clearly determines who is who to the nearest hertz.

The last line is not numbered. This is due to the fact that it is not included in the standard ten octaves. Pay attention to the column "Title 2". This contains the names of the octaves that are highlighted by musicians. These “strange” people have no concept of deep bass, but they have one octave above - from 20480 Hz. That is why there is such a discrepancy in numbering and names.

Now we can talk more specifically about the frequency range of speaker systems. We should start with some unpleasant news: there is no deep bass in multimedia acoustics. The vast majority of music lovers have simply never heard 20 Hz at a level of -3 dB. And now the news is pleasant and unexpected. There are no such frequencies in a real signal either (with some exceptions, of course). An exception is, for example, a recording from an IASCA Competition judge's disc. The song is called "The Viking". There, even 10 Hz are recorded with a decent amplitude. This track was recorded in a special room on a huge organ. The judges will decorate the system that wins over the Vikings with awards, like a Christmas tree with toys. But with a real signal everything is simpler: bass drum - from 40 Hz. Hefty Chinese drums also start from 40 Hz (among them, however, there is one megadrum. So it starts playing as early as 30 Hz). Live double bass is generally from 60 Hz. As you can see, 20 Hz is not mentioned here. Therefore, you don’t have to worry about the absence of such low components. They are not needed to listen to real music.

The figure shows a spectrogram. There are two curves on it: purple DIN and green (from old age) IEC. These curves display the spectrum distribution of the average musical signal. The IEC characteristic was used until the 60s of the 20th century. In those days, they preferred not to mock the squeaker. And after the 60s, experts noticed that listener preferences and music had changed somewhat. This is reflected in the great and mighty DIN standard. As you can see, there are much more high frequencies. But there was no increase in bass. Conclusion: no need to chase super-bass systems. Moreover, the desired 20 Hz was not put in the box there anyway.

Characteristics of acoustic systems

Now, knowing the alphabet of octaves and music, you can begin to understand the frequency response. Frequency response (amplitude-frequency response) - dependence of the oscillation amplitude at the device output on the frequency of the input harmonic signal. That is, the system is supplied with a signal at the input, the level of which is taken as 0 dB. From this signal, speakers with an amplification path do what they can. What they usually end up with is not a straight line at 0 dB, but a somewhat broken line. The most interesting thing, by the way, is that everyone (from audio enthusiasts to audio manufacturers) strives for a perfectly flat frequency response, but they are afraid to “strive.”

Actually, what is the benefit of the frequency response and why do the authors of TECHLABS constantly try to measure this curve? The fact is that it can be used to establish real frequency range boundaries, and not those whispered by the “evil marketing spirit” to the manufacturer. It is customary to indicate at what signal drop the boundary frequencies are still played. If not specified, it is assumed that the standard -3 dB was taken. This is where the catch lies. It is enough not to indicate at what drop the boundary values ​​were taken, and you can absolutely honestly indicate at least 20 Hz - 20 kHz, although, indeed, these 20 Hz are achievable at a signal level that is very different from the prescribed -3.

Also, the benefit of the frequency response is expressed in the fact that from it, although approximately, you can understand what problems the selected system will have. Moreover, the system as a whole. The frequency response suffers from all elements of the path. To understand how the system will sound according to the schedule, you need to know the elements of psychoacoustics. In short, the situation is like this: a person speaks within medium frequencies. That’s why he perceives them best. And at the corresponding octaves the graph should be the most even, since distortions in this area put a lot of pressure on the ears. The presence of tall narrow peaks is also undesirable. The general rule here is that peaks are heard better than valleys, and a sharp peak is heard better than a flat one. We will dwell on this parameter in more detail when we consider the process of measuring it.

Phase frequency response (PFC) shows the change in the phase of the harmonic signal reproduced by the speaker depending on the frequency. Can be uniquely calculated from the frequency response using the Hilbert transform. The ideal phase response, which says that the system has no phase-frequency distortions, is a straight line passing through the origin of coordinates. Acoustics with such a phase response are called phase-linear. For a long time, no attention was paid to this characteristic, since there was an opinion that a person is not susceptible to phase-frequency distortions. Now they measure and indicate in the passports of expensive systems.

Cumulative Spectral Attenuation (CSF) - a set of axial frequency response (frequency response measured on the acoustic axis of the system), obtained with a certain time interval during the attenuation of a single pulse and reflected on one three-dimensional graph. Thus, from the GLC graph one can accurately say which regions of the spectrum will decay at what speed after the pulse, that is, the graph allows one to identify delayed resonances of the AS.

If the KZS has many resonances after the upper middle, then such acoustics will subjectively sound “dirty”, “with sand on the high frequencies”, etc.

AC impedance - this is the total electrical resistance of the speaker, including the resistance of the filter elements (complex value). This resistance contains not only active resistance, but also the reactance of capacitors and inductances. Since reactance depends on frequency, impedance is also entirely dependent on it.

If they talk about impedance as a numerical quantity, completely devoid of complexity, then they speak about its modulus.

The impedance plot is three-dimensional (amplitude-phase-frequency). Usually its projections on the amplitude-frequency and phase-frequency planes are considered. If you combine these two graphs, you get a Bode plot. And the amplitude-phase projection is a Nyquist plot.

Considering that impedance depends on frequency and is not constant, you can easily determine from it how difficult the acoustics are for an amplifier. Also, from the graph you can tell what kind of acoustics it is (ZYa - closed box), FI (with a bass reflex), how individual sections of the range will be reproduced.

Sensitivity - see Thiel-Small parameters.

Coherence - coordinated occurrence of several oscillatory or wave processes in time. This means that the signal from different GG acoustic systems will arrive at the listener simultaneously, that is, it indicates the safety of phase information.

Listening Room Meaning

The listening room (among audiophiles is often shortened to KdP), and its conditions are extremely important. Some put the CDP in first place in importance, and only after that - acoustics, amplifier, source. This is somewhat justified, since the room is capable of doing whatever it wants with the graphs and parameters measured by the microphone. Peaks or dips in the frequency response may appear that were not observed during measurements in a quiet room. Both the phase response (following the frequency response) and the transient characteristics will change. In order to understand where such changes come from, we need to introduce the concept of room modes.

Room mods are the beautifully named room resonances. The sound is emitted by the speaker system in all directions. Sound waves bounce off everything in the room. In general, the behavior of sound in a single listening room (CLR) is completely unpredictable. There are, of course, calculations that allow us to evaluate the influence of various modes on sound. But they exist for an empty room with an idealized finish. Therefore, it is not worth presenting them here; they have no practical value in everyday life.

However, you must know that resonances and the reasons for their appearance directly depend on the frequency of the signal. For example, low frequencies excite room modes, which are determined by the size of the CDP. Bass boominess (resonance at 35-100 Hz) is a clear representative of the appearance of resonances in response to a low-frequency signal in a standard room of 16-20 m 2. High frequencies give rise to slightly different problems: diffraction and interference of sound waves appear, which make the directivity characteristics of the speakers frequency-dependent. That is, the directionality of the speakers becomes increasingly narrow with increasing frequency. It follows from this that the listener will receive maximum comfort at the intersection of the acoustic axes of the speakers. And only him. All other points in space will receive less information or receive it distorted in one way or another.

The influence of the room on the speakers can be significantly reduced if the control panel is muffled. For this, various sound-absorbing materials are used - from thick curtains and carpets to special slabs and cunning configurations of walls and ceilings. The quieter the room, the more the speakers contribute to the sound, and not the reflections from your favorite computer desk and pot of geraniums.

Recipes for placing speakers in a room

Vandersteen recommends placing speakers along the long wall of the room at points where low-frequency modes are least likely to occur. You need to draw a plan of the room. On the plan, divide the long wall successively into three, five, seven and nine parts, draw the corresponding lines perpendicular to this wall. Do the same with the side wall. The intersection points of these lines will indicate those places where the excitation of low frequencies in the room is minimal.

Lack of bass, lack of tight and clear bass:

try moving the speakers closer to the back wall;

check whether the stands under the speakers are stable: if necessary, use spikes or conical legs;

Check how solid the wall behind the speaker is. If the wall is flimsy and makes noise, place the speaker in front of a strong (solid) wall.

The stereo image does not extend beyond the space limited by the speakers:

move the speakers closer to each other.

There is no depth of sound space. There is no clear sound image in the center between the speakers:

select the optimal height for the speakers (use stands) and your listening position.

Sharp annoying sound in the mid and high frequencies:

if the speakers are new, warm them up on a music signal for several days;

Check for strong reflections from side walls or the floor in front of the listener.

Distortions

From subjectivism we need to move on to technical concepts. It's worth starting with distortions. They are divided into two large groups: linear and nonlinear distortions. Linear distortion do not create new spectral components of the signal; they change only the amplitude and phase components. (They distort the frequency response and phase response, respectively.) Nonlinear distortion make changes to the signal spectrum. Their number in the signal is presented in the form of nonlinear distortion and intermodulation distortion coefficients.

Harmonic distortion factor (THD, THD - total harmonic distortion) is an indicator characterizing the degree to which the voltage or current shape differs from the ideal sinusoidal shape. In Russian: a sinusoid is supplied to the input. At the output, it does not resemble itself, since the path introduces changes in the form of additional harmonics. The degree of difference between the signal at the input and output is reflected by this coefficient.

Intermodulation distortion factor - this is a manifestation of amplitude nonlinearity, expressed in the form of modulation products that appear when a signal is applied, consisting of signals with frequencies f 1 And f 2(based on the recommendation of IEC 268-5, frequencies are taken for measurements f 1 and f 2, such that f 1 < f 2/8. You can take another relationship between frequencies). Intermodulation distortion is assessed quantitatively by spectral components with frequencies f 2±(n-1) f 1, where n=2,3,... At the system output, the number of extra harmonics is compared and the percentage of the spectrum they occupy is estimated. The result of the comparison is the intermodulation distortion coefficient. If measurements are carried out for several n (usually 2 and 3 are sufficient), then the final intermodulation distortion coefficient is calculated from the intermediate ones (for different n) by taking the square root of the sum of their squares.

Power

We can talk about it for a very long time, since there are many types of measured speaker powers.

A few axioms:

Volume does not depend only on power. It also depends on the sensitivity of the speaker itself. And for an acoustic system, sensitivity is determined by the sensitivity of the largest speaker, since it is the most sensitive;

the indicated maximum power does not mean that you can apply it to the system and the speakers will play perfectly. Everything is just more unpleasant. Maximum power for a long time is highly likely to damage something dynamically. Manufacturer's warranty! Power should be understood as an unattainable limit. Only less. Not equal, and certainly not more;

little of! At maximum power or close to it, the system will play extremely poorly, because distortion will increase to completely indecent values.

The power of the speaker system can be electrical or acoustic. It is unrealistic to see the acoustic power on a box with acoustics. Apparently, so as not to scare off the client with a small number. The fact is that the efficiency (efficiency factor) of the GG (loudspeaker head) in a very good case reaches 1%. The usual value is up to 0.5%. Thus, the acoustic power of a system can ideally be one hundredth of its electrical potential. Everything else is dissipated in the form of heat, spent on overcoming the elastic and viscous forces of the speaker.

The main types of powers that can be seen on acoustics are: RMS, PMPO. This is electrical power.

RMS(Root Mean Squared - root mean square value) - average value of the supplied electrical power. Power measured in this way has a meaning. It is measured by applying a sine wave with a frequency of 1000 Hz, limited from above by a given value of total harmonic distortion (THD). It is imperative to study what level of nonlinear distortion the manufacturer considered acceptable, so as not to be deceived. It may turn out that the system is stated at 20 watts per channel, but the measurements were carried out at 10% SOI. As a result, it is impossible to listen to acoustics at this power. Also, the speakers can play at RMS power for a long time.

PMPO(Peak Music Power Output - peak music output power). What is the benefit of a person knowing that his system may suffer a short, less than a second, low frequency sine wave with high power? However, manufacturers are very fond of this option. After all, on plastic speakers the size of a child’s fist there can be a proud number of 100 Watts. There were no healthy boxes of Soviet S-90s lying around! :) Oddly enough, such figures have very little relation to the real PMPO. Empirically (based on experience and observations) you can obtain approximately real watts. Let's take the Genius SPG-06 as an example (PMPO-120 Watt). It is necessary to divide PMPO into 10 (12 Watts) and 2 (number of channels). The output is 6 watts, which is similar to the real figure. Once again: this method is not scientific, but is based on the author’s observations. Usually works. In reality, this parameter is not so large, and the huge numbers are based only on the wild imagination of the marketing department.

Thiel-Small parameters

These parameters completely describe the speaker. There are parameters both constructive (area, mass of the moving system) and non-structural (which follow from the constructive ones). There are only 15 of them. In order to roughly imagine what kind of speaker is working in the column, four of them are enough.

Speaker resonant frequency Fs(Hz) - resonance frequency of a speaker operating without acoustic design. Depends on the mass of the moving system and the rigidity of the suspension. It is important to know, since below the resonant frequency the speaker practically does not sound (the sound pressure level drops strongly and sharply).

Equivalent Volume Vas(liters) - the useful volume of the housing required for the speaker to operate. Depends only on the diffuser area (Sd) and the flexibility of the suspension. It is important because, when working, the speaker relies not only on the suspension, but also on the air inside the box. If the pressure is not what is needed, then the speaker will not work perfectly.

Full quality factor Qts - the ratio of elastic and viscous forces in a moving dynamic system near the resonance frequency. The higher the quality factor, the higher the elasticity in the dynamics and the more readily it sounds at the resonant frequency. It consists of mechanical and electrical quality factors. Mechanical is the elasticity of the suspension and the corrugation of the centering washer. As usual, it is the corrugation that provides greater elasticity, and not the external suspensions. Mechanical quality factor - 10-15% of total quality factor. Everything else is the electrical quality factor formed by the magnet and the speaker coil.

DC resistance Re(Ohm). There is nothing special to explain here. Resistance of the head winding to direct current.

Mechanical quality factor Qms- the ratio of elastic and viscous forces of the speaker; elasticity is considered only for the mechanical elements of the speaker. It is made up of the elasticity of the suspension and the corrugation of the centering washer.

Electrical quality factor Qes- the ratio of elastic and viscous forces of the speaker, elastic forces arise in the electrical part of the speaker (magnet and coil).

Diffuser area Sd(m2) - measured, roughly speaking, with a ruler. It has no secret meaning.

Sensitivity SPL(dB) - sound pressure level developed by the loudspeaker. Measured at a distance of 1 meter with an input power of 1 Watt and a frequency of 1 kHz (typical). The higher the sensitivity, the louder the system plays. In a two-way or more-way system, the sensitivity is equal to the SPL of the most sensitive speaker (usually the bass mug).

Inductance Le(Henry) is the inductance of the speaker coil.

Impedance Z(Ohm) is a complex characteristic that appears not on direct current, but on alternating current. The fact is that in this case, the reactive elements suddenly begin to resist the current. Resistance depends on frequency. Thus, impedance is the ratio of the complex voltage amplitude and the complex current at a certain frequency. (Frequency dependent complex impedance, in other words).

Peak power Pe(Watt) is PMPO, which is discussed above.

Weight of the moving system mms(d) is the effective mass of the moving system, which includes the mass of the diffuser and the air oscillating with it.

Relative hardness Cms(meters/newton) - flexibility of the moving system of the loudspeaker head, displacement under the influence of mechanical load (for example, a finger that aims to poke the speaker). The higher the parameter, the softer the suspension.

Mechanical resistance Rms(kg/sec) - active mechanical resistance of the head. Everything that can provide mechanical resistance in the head is included here.

Motor power BL- the value of magnetic flux density multiplied by the length of the wire in the coil. This parameter is also called the power factor of the speaker. We can say that this is the power that will act on the diffuser from the magnet side.

All of the above parameters are closely interrelated. This is pretty obvious from the definitions. Here are the main dependencies:

Fs increases with increasing rigidity of the suspension and decreases with increasing mass of the moving system;

Vas decreases with increasing suspension rigidity and increases with increasing diffuser area;

Qts increases with increasing rigidity of the suspension and mass of the moving system and decreases with increasing power B.L..

So, now you are familiar with the basic theoretical apparatus necessary to understand articles on acoustic systems. Let's move on directly to the testing methodology used by the authors of our portal.

Testing methodology

Frequency response Measurement technique and interpretation

At the beginning of this section, we will deviate a little from the main topic and explain why all this is being done. First, we want to describe our own method for measuring frequency response so that the reader does not have any additional questions. Secondly, we will tell you in detail how to perceive the resulting graphs and what can be said from the given dependencies, as well as what should not be said. Let's start with the methodology.

Measurement microphone Nady CM-100

Our technique for measuring frequency response is quite traditional and differs little from the generally accepted principles of conducting detailed experiments. Actually, the complex itself consists of two parts: hardware and software. Let's start with a description of the real devices that are used in our work. As a measuring microphone, we use a high-precision condenser microphone Behringer ECM-8000 with an omnidirectional polar pattern (omnidirectional), which has quite good parameters at a relatively low price. So to speak, this is the “heart” of our system. This instrument is designed specifically for use with modern technology as part of budget measurement laboratories. We also have at our disposal a similar microphone, the Nady CM-100. The characteristics of both microphones practically repeat each other, however, we always indicate with which microphone a particular frequency response was measured. As an example, here are the stated technical characteristics of the Nady CM-100 microphone:

impedance: 600 Ohm;

sensitivity: -40 dB (0 dB = 1 V/Pa);

frequency range: 20-20000 Hz;

maximum sound pressure: 120 dB SPL;

power supply: phantom 15…48 V.

Frequency response of the measuring microphone

M-Audio AudioBuddy microphone preamplifier

We use an external compact solution, M-Audio AudioBuddy, as a microphone preamplifier. The AudioBuddy preamplifier is designed specifically for digital audio applications and is optimized for use with microphones that require phantom power. Plus, the user has independent outputs at his disposal: balanced or unbalanced TRS. The main parameters of the preamplifier are:

frequency range: 5-50,000 Hz;

microphone gain: 60 dB;

microphone input impedance: 1 kOhm;

instrument gain: 40 dB;

instrument input impedance: 100 kOhm;

power supply: 9 V AC, 300 mA.

Sound card ESI Juli@

For further analysis, the signal from the output of the amplifier is fed to the input of a computer audio interface, which uses an ESI Juli@ PCI card. This solution can easily be classified as a semi-professional or even entry-level professional device. Main parameters:

number of I/O: 4 inputs (2 analog, 2 digital), 6 outputs (2 analog, 4 digital);

ADC/DAC: 24-bit/192 kHz;

frequency range: 20 Hz - 21 kHz, +/- 0.5 dB;

dynamic range: ADC 114 dB, DAC 112 dB;

inputs: 2 analog, 2 digital (S/PDIF Coaxial);

outputs: 2 analog, 2 digital (S/PDIF Coaxial or Optical);

MIDI: 1 MIDI input and 1 MIDI output;

interface: PCI;

synchronization: MTC, S/PDIF;

Drivers: EWDM driver support for Windows 98SE/ME/2000 and XP, MAC OS 10.2 or older.

In general, the unevenness of the path of the entire system in the frequency range 20-20000 Hz lies within +/- 1...2 dB, so our measurements can be considered quite accurate. The main negative factor is that all measurements are carried out in an average living room with standard reverberation. The area of ​​the room is 34 m2, the volume is 102 m3. The use of an anechoic chamber, naturally, increases the accuracy of the result obtained, but the cost of such a chamber is at least several tens of thousands of dollars, so only large manufacturers of acoustic systems or other very wealthy organizations can afford such a “luxury”. However, there are also tangible advantages to this: for example, the frequency response in a real room will always be far from the frequency response that was obtained by the manufacturer in the test chamber. Therefore, based on our results, we can draw some conclusions about the interaction of specific acoustics with the average room. This information is also very valuable, because any system will be operated in real conditions.

Popular utility RightMark Audio Analyzer

The second important point is the software part. We have several professional software packages at our disposal, such as RightMark Audio Analyzer ver. 5.5 (RMAA), TrueRTA ver. 3.3.2, LSPCad ver. 5.25, etc. As a rule, we use the convenient RMAA utility; provided it is freely distributed and constantly updated, it is very practical and provides high accuracy of measurements. In fact, it has already become a standard among test packages throughout the RuNet.

Program TrueRTA

Measuring module JustMLS programs LSPCAD

It would seem that any measurement should be carried out according to strictly established rules, but in the field of acoustics there are too many of these rules, and they often diverge somewhat from each other. For example, the basic standards and measurement methods are given in several very significant documents at once: outdated GOSTs of the USSR (GOST 16122-87 and GOST 23262-88), IEC recommendations (publications 268-5, 581-5 and 581-7), German DIN standard 45500, as well as American AES and EIA regulations.

We make our measurements as follows. The acoustic system (AS) is installed in the center of the room at the maximum distance from walls and three-dimensional objects; a high-quality stand 1 m high is used for installation. The microphone is installed at a distance of about a meter on a straight axis. The height is chosen in such a way that the microphone “looks” at approximately the central point between the midrange and tweeter speakers. The resulting frequency response is called the characteristic taken on the direct axis, and in classical electroacoustics it is considered one of the most important parameters. It is believed that the fidelity of reproduction directly depends on the unevenness of the frequency response. However, read about this below. We also always measure the angular characteristics of the system. Ideally, it is necessary to obtain a whole set of dependencies in the vertical and horizontal planes in increments of 10...15 degrees. Then it is quite reasonable to draw conclusions about the directional pattern of the speakers and give advice on the correct placement in space. In fact, the angular frequency response is no less important than the frequency response along the straight axis, since they determine the nature of the sound reaching the listener after reflection from the walls of the room. According to some reports, the share of reflections at the listening point reaches 80% or more. We also remove all possible characteristics of the path with all available frequency adjustments, modes such as 3D, etc.

Simplified flowchart of the measurement process

You can tell a lot from these graphs...

Subjective listening

So, the frequency response graphs have been obtained. What can you say after studying them in detail? In fact, a lot can be said, but it is impossible to unambiguously evaluate the system based on these dependencies. Not only is the frequency response not a very informative characteristic, and a whole series of additional measurements are required, for example, impulse response, transient response, cumulative spectrum attenuation, etc., but even from these comprehensive dependencies it is quite difficult to give an unambiguous assessment of acoustics. Strong evidence of this can be found in the official statement of the AES (Journal of AES, 1994) that subjective assessment is simply necessary to obtain a complete picture of the acoustic system in combination with objective measurements. In other words, a person can hear a certain artifact, but it is possible to understand where it comes from only by making a series of precise measurements. Sometimes measurements help to identify an insignificant defect that can easily slip past your ears when listening, and you can “catch” it only by focusing your attention on this particular range.

First, you need to break the entire frequency range into characteristic sections so that it is clear what we are talking about. Agree, when we say “mid frequencies”, it is not clear how much it is: 300 Hz or 1 kHz? Therefore, we suggest using a convenient division of the entire sound range into 10 octaves, described in the previous section.

Finally, we move directly to the moment of subjective description of sound. There are thousands of terms for assessing what is heard. The best option is to use some kind of documented system. And there is such a system, it is offered by the most authoritative publication with a half-century history, Stereophile. Relatively recently (in the early 90s of the last century), an acoustic dictionary, Audio Glossary, edited by Gordon Holt, was published. The dictionary contains an interpretation of more than 2000 concepts that in one way or another relate to sound. We propose to familiarize yourself with only a small part of them, which relates to the subjective description of sound in the translation by Alexander Belkanov (Magazine "Salon AV"):

ah-ax (rhymes with "rah" - Hurray). The coloring of vowels caused by a peak in the frequency response around 1000 Hz.

Airy - airiness. Refers to high frequencies that sound light, gentle, open, with a feeling of unlimited top end. A property of a system that has a very smooth response at high frequencies.

aw - (rhymes with "paw" [po:] - paw). The coloring of vowels caused by a peak in the frequency response around 450 Hz. Strives to emphasize and embellish the sound of large brass instruments (trombone, trumpet).

Boomy - read the word "boom" with a long "m". Characterizes an excess of mid-bass, often with a predominance of a narrow low-frequency band (very close to “one-note-bass” - bass on one note).

Boxy (literally “boxy”): 1) characterized by “oh” - the coloring of the vowels, as if the head is speaking inside the box; 2) used to describe the upper bass/low mids of speakers with excessive cabinet wall resonances.

Bright, brilliant - bright, with shine, sparkling. An often misused term in audio, it describes the degree of hardness of the edge of the sound being reproduced. Luminance refers to the energy contained in the 4-8 kHz band. This does not apply to the highest frequencies. All living sounds have brightness, the problem arises only when there is excess of it.

Buzz is a buzzing low-frequency sound that has a fluffy or sharp character due to some uncertainty.

Chesty - from chest (chest). A pronounced density or heaviness when reproducing a male voice due to excessive energy in the upper bass/lower midrange.

Closed-in (literally - hidden, closed). Needs openness, air and good detail. Closed sound is usually caused by HF roll-off above 10 kHz.

Cold - cold, stronger than cool - cool. Has some excess highs and weakened lows.

Coloration - coloring. An audible "signature" with which the reproducing system colors all signals passing through it.

Cool - cool. Moderately lacking in density and warmth due to monotonic decay starting at 150 Hz.

Crisp - crisp, clearly defined. Precisely localized and detailed, sometimes excessively due to the peak in the mid-HF range.

Cupped-hands - a mouthpiece made of palms. Coloration with a nasal sound or, in extreme cases, sound through a megaphone.

Dark - dark, gloomy (literally). Warm, soft, overly rich sound. It is perceived by ear as a clockwise slope of the frequency response throughout the entire range, so that the output level is attenuated with increasing frequency.

Dip (literally - immersion, failure). A narrow gap in the middle of a flat frequency response.

Discontinuity (literally - gap). Change in timbre or color during the transition of a signal from one head to another in multi-band acoustic systems.

Dished, dished-down - in the form of a saucer, an inverted saucer. Describes the frequency response with a failed middle. The sound has a lot of bass and high frequencies, the depth is exaggerated. Perception is usually lifeless.

Dry (literally - dry). Describes the quality of the bass: lean, lean, usually overdamped.

Dull (literally - dull, dull, boring, lethargic, depressed). Describes a lifeless, veiled sound. Same as “soft” - soft, but to a greater extent. An audible HF roll-off effect after 5 kHz.

her - rhymes with we. Coloration of vowels caused by a peak in the frequency response around 3.5 kHz.

eh - as in "bed". Coloration of vowels caused by a short rise in frequency response in the region of 2 kHz.

Extreme highs - ultra-high. The range of audible frequencies is above 10 kHz.

Fat (literally - plentiful, rich, fatty, oily). An audible effect of moderate redundancy in the mid and upper bass. Excessively warm, more "warm".

Forward, forwardness (literally - brought to the fore, moving forward). A reproduction quality that gives the impression that sound sources are closer than they were when recorded. Typically this is the result of a hump in the midrange plus the narrow directivity of the speakers.

Glare (literally - dazzling, sparkling). An unpleasant quality of hardness or brightness due to excessive low or mid-high energy.

Golden (literally - golden). A euphonious color, characterized by roundness, richness, and melody.

Hard (literally - hard, hard). Aspiring to steel, but not so piercing. This is often the result of a moderate hump around 6 kHz, sometimes caused by slight distortion.

Horn sound - a horn sound made through a horn. "aw" coloring, characteristic of many acoustic systems that have a mid-frequency horn driver.

Hot (literally - hot). Sharp resonant surge in high frequencies.

Hum (literally - buzzing). Continuous "itching" at frequencies that are multiples of 50 Hz. Caused by the penetration of the main frequency of the power supply or its harmonics into the playback path.

Humped (literally - hunched over). Characterizes the sound pushed forward (in terms of spatial characteristics). The overall sound is sluggish and meager. Caused by a broad rise in the mid frequencies and a fairly early fall in the lows and highs.

ih - as in the word "bit". Coloration of vowels caused by a peak in the frequency response around 3.5 kHz.

Laid-back (literally - pushed back, pushed back). Depressed, distant sounding, with exaggerated depth, usually due to a saucer-shaped midrange.

Lean - thin, skinny, frail. The effect of a slight downward decline in frequency response, starting from 500 Hz. Less pronounced than “cool” - cool.

Light - light. The audible effect of tilting the frequency response counterclockwise relative to the middle. Compare with "dark" - dark.

Loose - loose, loose, unstable. Refers to poorly defined/washed out and poorly controlled bass. Problems with damping of the amplifier or dynamic drivers/acoustic design of speakers.

Lumpy (literally - lumpy). A sound characterized by some discontinuity in the frequency response in the lower part, starting from 1 kHz. Some areas appear bulging, others appear weakened.

Muffled - muted. It sounds very sluggish, dull, and has no high frequencies in the spectrum at all. The result is a roll-off of high frequencies above 2 kHz.

Nasal (literally - nasal, nasal). It sounds similar to talking with a stuffy or pinched nose. Similar to the coloring of the vowel "eh". In loudspeaker systems, this is often caused by a measured pressure peak in the upper midrange followed by a dip.

oh - pronunciation as in "toe". The coloring of a vowel caused by a wide spike in the frequency response in the region of 250 Hz.

One-note-bass - bass on one note. The predominance of one low note is a consequence of a sharp peak in the lower range. Usually caused by poor damping of the woofer head, room resonances can also appear.

oo - pronunciation as in the word "gloom". The coloring of the vowel is caused by a wide surge in the frequency response in the region of 120 Hz.

Power range - maximum energy range. The frequency range of approximately 200-500 Hz corresponds to the range of powerful orchestral instruments - brass.

Presence range (literally - range of presence). The lower part of the upper range is approximately 1-3 kHz, creating a sense of presence.

Reticent (literally - restrained). Moderately set back. Describes the sound of a system whose frequency response is saucer-shaped in the midrange. Opposite of forward.

Ringing (literally - ringing). Audible resonance effect: coloration, smeared/fuzzy sound, shrillness, buzzing. It has the nature of a narrow surge in the frequency response.

Seamless (literally - without a seam, from a single/solid piece). There are no noticeable discontinuities throughout the entire audible range.

Seismic - seismic. Describes the reproduction of low frequencies that makes the floor seem to vibrate.

Sibilance (literally - whistling, hissing). Coloration emphasizing the vocal sound "s". It may be associated with a monotonic rise in the frequency response from 4-5 kHz or with a wide surge in the 4-8 kHz band.

Silvery - silvery. Somewhat harsh, but clear sound. It gives the flute, clarinet, and violas an edge, but the gong, bells, and triangles can be obtrusive and excessively sharp.

Sizzly - hissing, whistling. The frequency response rises in the region of 8 kHz, adding hissing (whistle) to all sounds, especially to the sound of cymbals and hissing in vocal parts.

Sodden, soggy (literally - wet, swollen with water). Describes loose and poorly defined bass. Creates a feeling of vagueness and illegibility in the lower range.

Solid-state sound - transistor sound, semiconductor sound. A combination of sonic qualities common to most solid-state amplifiers: deep, tight bass, slightly offset bright stage character and clearly defined, detailed treble.

Spitty (literally - spitting, snorting, hissing). A sharp “ts” is a coloring that overemphasizes musical overtones and sibilants. Similar to the surface noise of a vinyl record. Usually, the result is a sharp peak in the frequency response in the extreme HF region.

Steely - steely, steely. Describes shrillness, harshness, importunity. Similar to "hard", but to a greater extent.

Thick - fat, thick, dull. Describes a wet/dull or bulky, heavy bass sound.

Thin - liquid, frail, thinned. Very lacking in bass. The result is a strong, monotonous downward decay starting at 500 Hz.

Tizzy (literally - excitement, anxiety), “zz” and “ff” are the coloration of the sound of cymbals and vocal hisses, caused by an increase in the frequency response above 10 kHz. Similar to "wiry", but at higher frequencies.

Tonal quality - tonal quality. The accuracy/correctness with which the reproduced sound reproduces the timbres of the original instruments. (It seems to me that this term would be a good replacement for timbral resolution - A.B.).

Tube sound, tubey - sound due to the presence of tubes in the recording/playback path. A combination of sound qualities: richness (richness, liveliness, brightness of colors) and warmth, an excess of midrange and a lack of deep bass. Protruding image of the scene. The tops are smooth and thin.

Wiry - hard, tense. Causes irritation with distorted high frequencies. Similar to brushes hitting cymbals, but capable of coloring all sounds produced by the system.

Wooly - lethargic, vague, shaggy. Refers to loose, loose, poorly defined bass.

Zippy - lively, fast, energetic. Slight emphasis in the upper octaves.

So, now, looking at the given frequency response, you can characterize the sound with one or more terms from this list. The main thing is that the terms are systemic, and even an inexperienced reader can, by looking at their meaning, understand what the author wanted to say.

What material is the acoustics tested on? When choosing test material, we were guided by the principle of diversity (after all, everyone uses acoustics in completely different applications - cinema, music, games, not to mention different tastes in music) and the quality of the material. In this regard, the set of test disks traditionally includes:

DVDs with films and concert recordings in DTS and DD 5.1 formats;

discs with games for PC and Xbox 360 with high-quality soundtracks;

high-quality recorded CDs with music of various genres and genres;

MP3 discs with compressed music, material that is mainly listened to on MM acoustics;

special test CDs and HDCDs of audiophile quality.

Let's take a closer look at the test discs. Their purpose is to identify shortcomings in acoustic systems. There are test discs with a test signal and with musical material. Test signals are generated reference frequencies (allowing you to determine by ear the boundary values ​​of the reproduced range), white and pink noise, a signal in phase and antiphase, and so on. The popular test disk seems to us the most interesting F.S.Q. (Fast Sound Quality) and Prime Test CD . Both of these discs, in addition to artificial signals, contain fragments of musical compositions.

The second category includes audiophile discs containing entire compositions, recorded in studios of the highest quality and mixed with precision. We use two licensed HDCD discs (recorded at 24-bit and 88 kHz sampling frequency) - Audiophile Reference II (First Impression Music) and HDCD Sampler (Reference Recordings), as well as a CD sampler of classical music, Reference Classic, from the same label, Reference Recordings .

AudiophileReference II(the disc allows you to evaluate such subjective characteristics as musical resolution, involvement, emotionality and presence, the depth of the nuances of the sound of various instruments. The musical material of the disc is classical, jazz and folk works, recorded with the highest quality and produced by the famous sound wizard Winston Ma. On the recording You can find magnificent vocals, powerful Chinese drums, deep string bass, and on a truly high-quality system you can get real listening pleasure.

HDCDSampler from Reference Recordings contains symphonic, chamber and jazz music. Using the example of his compositions, one can trace the ability of acoustic systems to build a musical stage, convey macro- and microdynamics, and the naturalness of the timbres of various instruments.

ReferenceClassic shows us the real strong point of Reference Recordings - chamber music recordings. The main purpose of the disc is to test the system for faithful reproduction of various timbres and the ability to create the correct stereo effect.

Z-characteristic. Measurement technique and interpretation

Surely even the most inexperienced reader knows that any dynamic head, and, consequently, the speaker system as a whole, has a constant resistance. This resistance can be regarded as direct current resistance. For household equipment, the most common numbers are 4 and 8 ohms. In automotive technology, speakers with a resistance of 2 ohms are often found. The resistance of good monitor headphones can reach hundreds of ohms. From a physics point of view, this resistance is determined by the properties of the conductor from which the coil is wound. However, speakers, like headphones, are designed to operate with audio frequency alternating current. It is clear that as the frequency changes, the complex resistance also changes. The dependence characterizing this change is called the Z-characteristic. The Z-characteristic is quite important to study because... It is with the help of it that one can draw unambiguous conclusions about the correct matching of the speaker and amplifier, the correct calculation of the filter, etc. To remove this dependence, we use the LSPCad 5.25 software package, or more precisely, the JustMLS measuring module. Its capabilities are:

MLS Size (Maximum-Length Sequence): 32764,16384,8192 and 4096

FFT (Fast Fourier Transform) size: 8192, 1024 and 256 points used in different frequency bands

Sampling rates: 96000, 88200, 64000, 48000, 44100, 32000, 22050, 16000, 1025, 8000 Hz and user selectable Custom.

Window: Half Offset

Internal representation: From 5 Hz to 50000 Hz, 1000 frequency points with logarithmic periodicity.

To measure, you need to assemble a simple circuit: a reference resistor (in our case C2-29V-1) is connected in series from the speakers, and the signal from this divider is fed to the input of the sound card. The entire system (speaker/AC+resistor) is connected through an AF power amplifier to the output of the same sound card. We use the ESI Juli@ interface for these purposes. The program is very convenient because it does not require careful and lengthy setup. Just calibrate the sound levels and press the "Measure" button. In a split second we see the finished graph. Next comes its analysis; in each specific case we pursue different goals. So, when studying a low-frequency speaker, we are interested in the resonant frequency to check the correct choice of acoustic design. Knowing the resonant frequency of the high-frequency head allows you to analyze the correctness of the isolation filter solution. In the case of passive acoustics, we are interested in the characteristic as a whole: it should be as linear as possible, without sharp peaks and dips. So, for example, acoustics whose impedance sags below 2 ohms will not be to the taste of almost any amplifier. These things should be known and taken into account.

Nonlinear distortions. Measurement technique and interpretation

Total Harmonic Distortion (THD) is a critical factor when evaluating speakers, amplifiers, etc. This factor is due to the nonlinearity of the path, as a result of which additional harmonics appear in the signal spectrum. The nonlinear distortion factor (THD) is calculated as the ratio of the square of the fundamental harmonic to the square root of the sum of the squares of the additional harmonics. Typically, only the second and third harmonics are taken into account in calculations, although accuracy can be improved by taking into account all additional harmonics. For modern acoustic systems, the nonlinear distortion factor is normalized in several frequency bands. For example, for the zero complexity group according to GOST 23262-88, the requirements of which significantly exceed the minimum requirements of the IEC Hi-Fi class, the coefficient should not exceed 1.5% in the frequency band 250-2000 Hz and 1% in the frequency band 2-6.3 kHz. Dry numbers, of course, characterize the system as a whole, but the phrase “THE = 1%” still says little. A striking example: a tube amplifier with a non-linear distortion coefficient of about 10% can sound much better than a transistor amplifier with the same coefficient of less than 1%. The fact is that lamp distortion is mainly caused by those harmonics that are screened by auditory adaptation thresholds. Therefore, it is very important to analyze the spectrum of the signal as a whole, describing the values ​​of certain harmonics.

This is what the signal spectrum of a specific acoustic looks like at a reference frequency of 5 kHz

In principle, you can look at the distribution of harmonics across the spectrum using any analyzer, both hardware and software. The same programs RMAA or TrueRTA do this without any problems. As a rule, we use the first one. The test signal is generated using a simple generator; several test points are used. For example, nonlinear distortions that increase at high frequencies significantly reduce the microdynamics of the musical image, and a system with high distortions as a whole can simply greatly distort the timbral balance, wheeze, have extraneous sounds, etc. Also, these measurements make it possible to evaluate the acoustics in more detail in combination with other measurements, and check the correctness of the calculation of the separation filters, because the nonlinear distortions of the speaker increase greatly outside its operating range.

Article structure

Here we will describe the structure of the article on acoustic systems. Despite the fact that we try to make reading as pleasant as possible and do not squeeze ourselves into a certain framework, articles are compiled taking into account this plan, so that the structure is clear and understandable.

1. Introduction

Here we write general information about the company (if we are getting to know it for the first time), general information about the product line (if we are taking it for a test for the first time), and we give an outline of the current state of the market. If the previous options are not suitable, we write about trends in the acoustics market, in design, etc. - so that 2-3 thousand characters are written (hereinafter - k). The type of acoustics is indicated (stereo, surround sound, triphonic, 5.1, etc.) and positioning on the market - as a multimedia gaming for a computer, universal, for listening to music for an entry-level home theater, passive for a home theater, etc.

Tactical and technical characteristics summarized in the table. Before the table with performance characteristics, we make a short introduction (for example, “we can expect serious YYY parameters from acoustics costing XXX”). The table type and set of parameters are as follows:

For systems2.0

For systems2.1

For 5.1 systems

We take the tables given as a basis; if additional data is available, we make additional columns; columns for which there is no data, we simply remove them. After the table with performance characteristics, some preliminary conclusions.

3. Packaging and accessories

We describe the delivery package and box, at least two photographs. Here we evaluate the completeness of the kit, describe the nature of the cables included in the kit, and, if possible, estimate their cross-section/diameter. We conclude that the kit corresponds to the price category, convenience and packaging design. We note the presence of a Russian-language operating manual and its completeness.

4. Design, ergonomics and functionality

We describe the first impression of the design. We note the nature of the materials, their thickness, quality factor. We evaluate design decisions in terms of their potential impact on sound (remembering to add the word “allegedly”). We evaluate the quality of workmanship, the presence of legs/spikes, grill/acoustic fabric in front of the diffusers. We are looking for fastenings, the possibility of installation on a stand/shelf/wall.

Describes ergonomics and impressions of working with acoustics (excluding listening). It is noted whether there is a click when turned on, whether the wires are long enough, and whether all controls are convenient to use. Implementation of controls (analog sliders or knobs, digital encoders, toggle switches, etc.) Several photographs of controls, remote control if available, photos of speakers in a setting or in comparison with ordinary objects. Convenience and speed of switching, the need to check phasing, whether the instructions help, etc. We note the effectiveness of magnetic shielding (on a CRT monitor or TV). We pay attention to additional inputs, operating modes (pseudo-surround sound, built-in FM tuner, etc.), service capabilities.

5. Design

We disassemble the speakers, if there is a subwoofer, then that too. We note the following design features:

Type of acoustic design (open, closed box, bass reflex, passive radiating, transmission line, etc.) + general photo of the internal structure;

Dimensions and internal volume of the case, assume the compatibility of the AO with the GG;

Location of loudspeaker heads (SG), method of attachment to the acoustic design;

Quality of internal installation, assembly, fastening + 1-2 photos with internal installation details;

Availability of mechanical damping, quality of its execution and materials used + photo;

The shape and dimensions of the bass reflex (if any), its location (estimated effect on the sound) and the manufacturer’s likely adaptations to eliminate jet noise + photo;

The quality of internal wiring, the presence of overload protection, proposals for modernization;

The GGs used are the type, material of manufacture (paper, impregnated silk, aluminum, plastic, etc.), the nature of the diffuser surface (conical, exponential surface, corrugated, with “stiffening ribs,” etc.) and the protective cap (flat , “acoustic bullet”, etc.), suspension (rubber, paper, etc.), degree of suspension rigidity), coil diameter, tweeter cooling, markings, resistance + photo of each GG;

Type of fastening of the wire to the speakers (detachable, screw clamps, spring clamps, banana clamps, etc.) + photo;

Signal cable connectors - types, quantity, quality.

We illustrate the following with diagrams and graphs:

Amplifier chip(s) - table with key characteristics, their analysis for compliance with performance characteristics and speakers, if possible - provide a graph of power versus SOI and a photo, maybe a photo of the radiator;

Power transformer - table with currents, type of transformer (torus, on W-shaped plates, etc.) indicating the total power in VA, conclusions about the availability of power supply reserve, the presence of a power filter, etc. + photo;

Separation filter - we sketch the circuit, indicate the order of the filter (and, accordingly, the attenuation of the signal), and draw a conclusion about its justification; application (if appropriate measurements are available), we calculate the cutoff frequency if we subsequently measure resonance and/or Z-characteristic;

We calculate the resonant frequency of the bass reflex, present the formula and justify its use.

6. Measurements

We make the following measurements and provide an analysis for each of them, making assumptions about the nature of the sound.

Axial frequency response of the column with detailed analysis;

Frequency response of speakers at angles of 30 and 45 degrees, analysis of the nature of speaker dispersion;

Frequency response of the subwoofer (if any) + total frequency response of systems, quality analysis; trifonic matching, influence of bass reflex resonance;

Axial frequency response depending on tone controls (if any);

Frequency response of the bass reflex, analysis;

Harmonic distortion spectrum;

Frequency response of speakers separately (for example, LF and HF), if necessary.

7. Audition

First, we give the first subjective assessment of the nature of the sound, indicating whether the volume is sufficient for various playback modes. We note the peculiarities of the acoustics in each of the typical applications - cinema (for 5.1 systems we focus on the quality of positioning), music and games. We indicate the type of listening room, its area and volume, as well as the degree of demands of the given acoustics on the room. Next, we analyze the sound of the speakers using the list of characteristics and terminology described above. We try to avoid subjective comments and, at every opportunity, make a reference to the measurement result that confirmed this or that sound feature. In general, all sound analysis is done in conjunction with measurements. Be sure to pay attention to the following parameters:

The nature of the acoustics in each of the key frequency ranges, the extent to which one or another range is emphasized;

The nature and quality of the stereo effect (the width of the stage, the positioning of sound sources and instruments on it); for 5.1 acoustics, a separate assessment of spatial positioning is given. Don’t forget to place the acoustics correctly (the angle to the front pair is 45 degrees, the distance is slightly greater than the stereo base, the rear pair is twice as close to the listener as the front pair, all speakers are at ear level);

Detail, sound transparency, “grain” (post-pulse activity at mid and high frequencies);

The presence of color and its character in different ranges, timbral balance and natural sound;

Clarity of sound attack (impulse response) and separately - subwoofer operation (if any);

Signal saturation with harmonics (warmth or coldness of sound);

Micro- and macrodynamics of sound, detail of background sounds, “openness” or “tightness” of sound (width of the dynamic range, quality of the transient response of the GG);

Optimal values ​​for tone controls.

Here we give a general assessment of the acoustics, first of all, the compliance of the solutions used in it with the final result and price category. It is assessed whether the acoustics are successful, promising, and suitable as a “blank” for modifications. A list of pros and cons of the system is given.

Conclusion

The assiduous reader, having completed reading this article, probably learned something new and interesting for himself. We did not try to embrace the immensity and cover all possible aspects of the analysis of acoustic systems and, especially, sound theory; we will leave this to specialized publications, each of which has its own view of the line where physics ends and shamanism begins. But now all aspects of acoustics testing by the authors of our portal should be extremely clear. We never tire of repeating that sound is a subjective matter, and you cannot be guided by tests alone when choosing acoustics, but we hope that our reviews will greatly help you. Have a good sound, dear readers!

IntroductionIt is unlikely that I will make a discovery by calling the topic of testing computer acoustics one of the most unpopular in the computer press. If we analyze the majority of reviews, we can come to the conclusion that they are all purely descriptive in nature and consist, as a rule, of recompiling press releases with rewriting of the main technical parameters, admiring the body design, and extremely subjective final assessments, not supported by any evidence. The reason for this “dislike” is the lack of such specialized measuring instruments at the testers’ disposal as audio analyzers, sensitive microphones, millivoltmeters, sound signal generators, etc. Such a set of equipment costs a lot of money, and for this reason not every test laboratory can afford it (especially that computer acoustics costs disproportionately little compared to similar measuring equipment). In addition, the tester, of course, must have the “right ears” and, preferably, have an idea of ​​​​quality sound not from his home music center, but from the sound of a symphony orchestra in the conservatory hall, for example. Be that as it may, although computer acoustics do not pretend to take the place of hi-end and delight the user’s ears with a reliable transmission of timbres, accurately conveying the emotional content of the sound picture, they should at least not distort the sound of a number of instruments and not introduce discomfort into the listener’s consciousness. Objectively, the human ear, of course, neutralizes most of the distortions, isolating and restoring the sound picture even from the crackling sound of a radio broadcast loudspeaker, but when listening to the same work on higher-quality acoustics, the listener begins to distinguish new and additional details, some musical shades (like that “...if you look with the naked eye, you can see three stars!..”). Probably for this reason too, the choice of computer acoustics should be approached more seriously and consciously.
Recently, the number of users who want to equip their computer with truly high-quality speaker systems has been steadily growing. To make the task of choosing easier for you, we decided to develop this topic on the pages of our website, and in order for the reviews not to be purely subjective in nature and not based only on the personal preferences of the author-tester, F-Center equipped the test laboratory with a special device - the PRO600S audio analyzer produced French company Euraudio. Let's look at this device in a little more detail.

Audio analyzer Euraudio PRO600S

Neutrik microphone



High-SPL microphone Linearx M52



Jack for connecting an external microphone

Mode for measuring electrical circuits using linear input

On the rear panel of the audio analyzer there is: line input (1), built-in microphone (2), power switch (3), connector for connecting an external power supply (4), COM port (5), LPT port (6)

Selecting the input source

Selecting a weighing method



Sound competition mode

Curves "A" and "C"

Frequency response measurement using Euraudio PRO600S

Real-time frequency response measurement mode for sound pressure

Maximum sound pressure level measurement mode

Impedance measurement

Impedance measurement circuit

IASCA Competition Audio Test CD

IASCA Competition CD playlist