This page contains diagrams of Radiotehnika acoustic systems of class S90 diagram (35AC-212, S90, S90B, S90D, S90F, S-90E), detailed description, speaker parameters, photos.

Pretty high-quality Soviet-era acoustics, after minor modifications and restoration, I can say with confidence that it will give odds to many modern acoustic systems.

If you have similar ones lying around or bought them somewhere on the cheap, then put them in order and they will delight you for a long time with powerful basses, saturated with medium and high frequencies in musical works of any style and direction, in general, I RECOMMEND!!!

Acoustic system S-90 (first model)

Rice. 1. Appearance of the Radiotehnika S-90 speakers.

The speaker system has two step playback level controls separately for medium and high frequencies in the ranges from 500 to 5000 Hz and from 5 to 20 kHz, respectively.

Both controls have three fixed positions: "0", "-3 dB" and "-6 dB". In position "0" signal with separation filter is fed directly to the corresponding head. In the "-3 dB" and "-6 dB" positions, the signal is attenuated relative to the "0" position by 1.4 and 2 times, respectively.
With the appropriate spectral composition of the program, switching the controller changes the timbre of the sound.

Passport specifications S-90:

Rice. 2. circuit diagram speakers S90 35AC-212.

Acoustic system S-90 35AC-1

Rice. 3. Acoustic system Radio engineering S-90 35AC-1, appearance, photo.

Rice. 4. Schematic diagram of AC Radiotehnika S90 35AC-1.

Acoustic system Radiotehnika S-90B

Rice. 5. Appearance of acoustic systems Radio engineering S-90B.

Acoustic system S-90D

Rice. 6. Appearance of acoustic speakers Radiotehnika S-90D.

The speakers have an overload indicator for the loudspeaker heads. The regulators located on the front panel of the speakers make it possible to smoothly adjust the sound pressure level of the high-frequency and mid-frequency loudspeaker heads in the range from 0 to minus 6 dB.

There is also a model of the acoustic system "S-100D", it uses a mid-frequency head 30 GDS-3 with magnetic fluid MAHID, which allows you to increase the nameplate power of the speaker system up to 100 watts. The rest of the designs "S-90D" and "S-100D" are similar.

For operation, the speakers must be connected to an amplifier that has the highest (maximum) power at the output of each channel, ranging from 50 to 150 watts.

If during operation of the speaker the OVERLOAD indicators begin to glow, then the level of the input signal supplied to it should be reduced (by the volume control in the amplifier to which the speaker is connected).

Passport specifications S-90D:

The figure below shows

38444

Modernization of the S-90 speakers by replacing standard cases with a labyrinth design of woofers

Labyrinth design upgrade S-90 filling of squares with cotton wool and sticker on the inner surface of the woolen blanket
At first, only the frontal knees of the labyrinth were covered with wool, then the side surfaces too.
Finished labyrinth S-90 with wool-pasted inner surfaces

Alteration of the most famous speakers of the USSR Radio engineering S-90

Alexander Rogozhin came up with a know-how on how to translate the most well-known to most Russian-speaking people the speakers of Radio Engineering S-90 into labyrinth cases. The article is devoted to the most massive and for more than 20 years considered the standard acoustics of the Soviet period, which in its first generation was called 35AC-1. And Rogozhin proposes to make columns with the name "Cheap, loud and super-bass" out of 35AS-1 (Radio engineering S-90)!

Ode to speakers Radio engineering S-90 (35AC-1)

There is no such person who speaks Russian, Ukrainian, Belarusian, who at least once in his life did not hear the famous Soviet speakers Radiotekhnika S-90, or did not have on the mezzanine, in the closet, at home or on the hacienda one of their modifications produced in over 30 years. You can think anything about their sound, appearance, rubber speakers, but in fact these are the MOST common "People's" speakers in the expanses of the former USSR. They still work in tens of thousands in the systems of music lovers, who feel sorry for throwing them away. compared to the branded "remake" they play very, very worthy.

If a person is faced with a choice on which speakers to listen to music: with bass, loudly, and for ridiculous money, then despite all the disadvantages of Radio Engineering S-90, they have practically no competitors, and before they were even more so. In the late USSR, in addition to the S-90 speakers, of course, “clones” appeared, torn off from the best foreign samples, for example, Elektronika 100AC063 or 75AC-063. But they were very expensive and not widely used, they could not compete in popularity with the S-90 acoustics. It was impossible in principle to get three full-fledged bands from any other speakers with the same power as the S-90, 10 inch woofer and almost for nothing. Now this is even more relevant.

Tens of thousands of these speakers are still working in the rooms of young and not very people who do not have the opportunity to carry out complex projects on expensive imported dynamic heads. For obvious reasons, many of our compatriots are in no hurry to abandon the Radio Engineering S-90 acoustics. They are not eager to run to the store and buy beautiful branded speakers, which for the most part differ from the S-90 only in appearance, which often cannot be said about their sound.

Nevertheless, we all love to listen to music, everyone is in a good mood when you want to turn it on “to its fullest”. Everyone loves high-quality bass, without which almost any music loses its foundation and most of its emotions. Many styles of music without bass are generally impossible to listen to, because. without it, the lion's share of important musical information is lost. The soul asks WOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOL! And the low frequencies are actually a very thin thing, in order to adequately sound and impress, they ask for large speakers, cabinets and capacities. But even with all this (in large speakers like the S-90), the bass often turns out to be buzzing, drawn out and indistinct, and does not give us the “buzz” that it is supposed to give. We quickly get tired of such a bass and start turning the tone control knobs or switching the equalizer modes on the receiver. And instead of getting pleasure - to get annoyed and think about the imperfection of this mortal world ... Almost all music lovers and owners of this acoustics, in particular, have found themselves in such a situation more than once.

Low frequency problems S-90

The reason that over the past 30 years the owners of the Radio Engineering S-90 acoustics and its numerous modifications are not satisfied with its sound and are somehow trying to cope with this problem lies in several reasons. The main problem of the S-90 speakers, confirmed by repeated research by specialists, is a mistake made when designing the low-frequency design of the 30GD-2 speaker. Having gone into the series, the error led to the fact that the potential for high-quality reproductions originally incorporated in the Radio engineering S-90 model and its modifications low frequencies, is not implemented even by 20-30% of the possible ones.

A huge number of S-90 owners, almost from the moment they appeared on sale in the 80s to the present day, have been trying to improve the low frequencies of these speakers by conjuring with filters, reworking the phase inverter pipes, strengthening their native cases and filling them with anything.

Dear music lovers! I urge you to stop doing nonsense, because. it is absolutely useless ... S-90 speakers from the factory have a case with a volume of only 45 liters - NOT corresponding to the optimal mode of operation of the 30GD-2, 75GDN1-4 speaker installed in it. You can even trim it with the root of rare breeds and glue it on all sides with porous rubber - it will NOT work correctly anyway.

That is, the question of a radical improvement in the operation of these speakers at low frequencies, regrettable as it may seem - the question of replacing the case, rises to its full height.

The task is somewhat complicated by the fact that in 30 years great amount modifications of the 35AC-1 speakers with 30GD2/75GDN1-4 low-frequency speakers (8), which have a large spread of parameters. In the new cases, this problem is largely solved and allows speakers from the earliest releases to the latest ones to feel right. The tuning of the new cabinets is "stretched" and allows NOT to engage in the selection of low-frequency speakers on purpose.

Midrange problemsS-90

Almost all owners of s-90 speakers note nasty overtones and a large uneven return at mid frequencies, which become especially noticeable at medium and high volumes. All the grandiose filter conversion projects by installing expensive imported capacitors, replacement of wires, resistors, etc. as well as options for gluing halves of a tennis ball onto the diffuser of mid-frequency heads, etc. fail.

The main reason for the unsatisfactory sound at medium frequencies is not the 15GD-11 speaker at all, but its acoustic design. This “glass” that covers the midrange head at the back has a meager volume and is the second mistake made by the engineers who designed the S-90 speakers. Everything is wrong with the “glass” of the mid-frequency head 15GD-11 (20GDS ...), starting from the volume and configuration, ending with the internal design. When replacing the s90 speaker cabinet with the correct one from the point of design of the woofer, the midrange speaker should also be designed accordingly.

Of course, replacing the “minor” regular glass with an acoustic design that is optimal in terms of volume and shape will not make the 15GD11 head a different speaker, but will give it the opportunity to do what it can do initially.

What can you get

As a result, the updated S-90 speakers will sound radically different not only at low, but also at medium frequencies. Presented on the Internet big number attempts to remake the S-90 speakers in order to "deceive everyone" and turn them into studio monitors. Attempts concern everything, but not the replacement of the main "weak point" - the hull, and most often turn out to be a failure. While keeping the S-90 speaker cabinets intact, to radically change the sound, you need to change the speakers to modern ones or design three-way speakers from scratch, which most music lovers do not dare to do.

I propose to leave the native equipment of the S-90 speakers intact. Their value is in the minimum budget and no matter how clever, proven by decades of operation in the most severe conditions - performance.

There is one thing about these speakers that can be fundamentally improved, which is to “get the most out of its speakers”. To do this, to the native set of speakers and filters, you need to make an acoustically correct case. As a result, you can reach a fundamentally new level of sound quality of these speakers, without spoiling anything.

As a bonus, you can not throw away the old cases and, if necessary, collect the "stock" S-90 back and sell it to any lover of authentic speakers made in the USSR.

Problems of native boxesS-90

• The wrong amount of low-frequency design does not give the desired level of pressure on the bass;
• A non-optimal bass reflex tuning frequency leads to uneven bass response and poor bass quality;
• The type of low-frequency design "phase inverter" in combination with a "tight" speaker on a rubber suspension leads to an extended and monotonous "buzz" at low frequencies, instead of a clear percussive bass;
• Phase-inverted acoustic design leads to a significant uneven sound pressure at low frequencies in the room, and makes demands on obtaining high power from the amplifier;
• The weak walls of the boxes of the S-90 speakers lead to a loss of efficiency at low frequencies and give noticeable overtones when working at high volumes;
• Poor sealing of the drawers does not allow even the low-frequency design that the S-90 speakers have in the stock version to work;
• The extremely small volume of the cap of the mid-frequency head 15GD11 (20GDS-) leads to the “tightness” of the mid-frequency dynamics;
• Suboptimal damping of a small midrange box leads to noticeable overtones and “nasal” in the midrange;
• The shape and dimensions of the stock S-90 speaker cabinets require them to be mounted on furniture, which leads to “shaky position” of the speakers, resonance of the furniture at high volumes and, as a result, a deterioration in the sound of low frequencies;
• The “low-profile” shape of the speaker cabinets requires them to be mounted on specialized speaker stands, which ultimately increases the cost of the system. Placing the 35AC-1s on the floor results in a lack of high frequencies and an incorrect stage.

Benefits of the new buildings

• The design of the low-frequency head is a quarter-wave labyrinth with its radical advantages at low frequencies over a phase inverter (detailed description here);
• Optimally calculated frequency and Q-factor tuning of the quarter-wave resonator gives a wide band and an optimal level of low frequencies;
• The highest rigidity of the box gives the highest possible efficiency, clean, elastic and biting sound at low frequencies;
• Rigid boxing of a large volume of the midrange head gives a lively and open middle and clear vocals;
• The location of the midrange and tweeters on the front panel, respecting the distances to the walls of the case according to the "golden section" principle, reduces diffraction phenomena on vocals and high frequencies and makes the sound much more comfortable;
• With the new enclosures, the acoustics turns into a classic floor-standing design with midrange and tweeters optimally located in height;
• The speakers have narrower and taller fronts than standard S-90s and do not require any kind of stands. The appearance of the speakers is improved many times over.

Manufacturer: PO "Radio engineering", Riga.

Purpose and scope : For high-quality reproduction of music and speech programs in stationary domestic environments. The S-90 speaker system, developed in 1975, is the first domestic system that meets the requirements of international documents for equipment of the Hi-Fi category. Later models of this speaker "S-90B" and "S-90D" are distinguished by an extended range of reproducible frequencies. The introduction of loudspeaker electrical overload indication and new appearance. The recommended power of a high-quality household amplifier is 20 - 90 watts. 35 AC-212 “S-90” and 35 AC-012 “S-90”, similar to AC, the difference lies in GOST.

Characteristics

3-way tower speaker with bass reflex

Frequency response: 25 (-15 dB) - 25000 Hz

Frequency response unevenness in the range of 100 - 8000 Hz: ±4 dB

Sensitivity: 85 dB (0.338 Pa/√W)

Directionality at angles of 25 ± 5 ° in the horizontal plane and 7 ± 2.5 ° in the vertical plane, from the frequency response measured along the speaker acoustic axis:

vertical: ±8°

horizontal: ±6°

Harmonic distortion speakers at a sound pressure level of 90 dB at frequencies:

250 - 1000 Hz: 2%

1000 - 2000 Hz: 1.5%

2000 - 6300 Hz: 1%

Resistance: 4 ohm

Minimum impedance value: 3.2 ohms

Rated power: 35W

Limiting (passport) power: 90 W

Short-term power: 600W

Weight: 23 kg

Dimensions (HxWxD): 710x360x285 mm

Installed Speakers:

LF:

MF:

HF:

Design

The case is made in the form of a rectangular non-separable box made of chipboard, veneered with fine wood veneer. Wall thickness 16 mm, front panel - plywood 22 mm thick. Elements are installed at the joints of the body walls from the inside, which increase the strength and rigidity of the body.

The heads are each framed with decorative black overlays, made of stamped aluminum sheet, with four fixing holes. The midrange head on the inside is isolated from the total body volume by a special plastic casing in the shape of a truncated cone. The bass head is located on the front panel along the vertical axis, and the midrange and treble heads are shifted to the left and right relative to this axis. On the front panel there are also handles for midrange and treble level controls, and in its lower part there is a plastic overlay panel with a nameplate and a rectangular hole 100X80 mm, which is the phase inverter output. The nameplate shows frequency response curves corresponding to various positions of the level controls, as well as the name of the speaker and the manufacturer's logo. In addition, there are bushings on the front panel for attaching a decorative frame with fabric. On the back wall, in the lower part, a block with terminals is attached. Each head from the side of the front panel is protected by blackened metal mesh.

The internal volume of the speaker is 45 liters. To reduce the impact on the frequency response of sound pressure and the sound quality of the AC resonances of the internal volume of the case, it is filled with a sound absorber, which is mats of technical wool covered with gauze.

Inside the case, on one board, there are electrical filters that provide separation of the AC bands. Crossover frequencies between LF/MF – 750±50 Hz, between MF/HF – 5000±500 Hz. In the design of the filters and the overload indication unit, resistors of the VS, MLT, SP3-38B, S5-35I, PPB types, capacitors of the MBGO-2, K50-12, K75-11 types and inductors on plastic molded frames were used.

The package included: four plastic legs that can be attached to the base of the case; removable decorative frame, covered with knitted fabric with high acoustic transparency.

Who doesn't remember the famous S-90 speakers from the 70s? (In fact, there was a Latin letter S, and therefore this Riga product was called the Radiotehnika S-90 speaker system, but the habit of distrusting everything foreign also came from this time, and then not everyone knew that the Balts use the Latin alphabet.) Dancing regulars in the club (called discos in the 80s) they did not go into such details, and therefore they still call these speakers S-90. This article will be devoted to literally legendary acoustics of the Soviet times.

Nostalgia

"Radio engineering S-90" was considered one of the the best systems of that time and was in demand everywhere. Concerts in the houses of culture of the most remote corners of our country, amateur performances, school evenings with songs and dances - everywhere this equipment was indispensable. Some irresponsible comrades risked rehearsals at home, and the S-90 speakers created an unforgettable sound effect in absolutely all apartments of the five-story panel building. The "gratitude" of the neighbors was also indescribable. They can be understood. Even if the owner "turned on" the average volume, extraneous sounds they simply evaporated: the howling of dogs disappeared somewhere, the sound of neighbors on the batteries, as well as the sound of sluggish bass from ordinary speakers two floors above.

The column "Radio Engineering" announced either an approaching earthquake, or a military fighter jet hitting the roof at a low level. The chandeliers bounced, the crystal in the sideboards tinkled thinly, and everything in the room that was not fixed clearly vibrated. Although it must be said that the S-90 speakers were not considered the most powerful in their class, and they were not, an amplifier was installed to them. By the way, working versions of this equipment are in great demand even today. It is worth such, even heavily used retro equipment is very expensive. The column "Radio Engineering" of any modification in working order will cost from four thousand rubles. One!

Description

The acoustic system "Radio engineering" of the highest (zero) class 35 AS-1 went on sale in 1977 and was immediately named S-90. The speakers had the best characteristics for those times, especially considering that only Soviet equipment was in use. They were developed purely for domestic use, and the Orbita design bureau at the Riga Radio Engineering Production Association was engaged in this. Subsequently, the entire series of these acoustic systems received the S-90 brand.

The speakers fully justified their characteristics, they were not inferior to imported ones in anything, significantly surpassing all domestic ones. In order for the sound of the speaker system to be full, an amplifier such as "Electronics" or "Amfiton" was necessarily connected to it. In the frequency range from 31.5 to almost 20 kHz, the speakers worked with a rated power of 35 watts. Moreover, the passport indicated the power of ninety. The sound pressure, the results of which are written above, was 1.2 Pa.

About the disadvantages

The weight of one column sometimes exceeded thirty kilograms. They cost three hundred rubles per pair (an engineer earned from ninety to one hundred and twenty rubles a month). However, few people saw them in free sale. Many people bought S-90 music speakers one at a time, despite the fact that there were no guarantees that when buying a second one, they would be able to make a well-tuned pair of them. However, even if a pair was bought, no one guaranteed its balance either: for example, the right column of the S-90 gathered all its power together and persistently sounded louder than the left one. This is despite the fact that the equipment was positioned as having the highest quality category.

This drawback is not the only one that the C-90 column could have. Tweeters often failed because thin and weak wires were not very practical on their own. At medium frequencies, the sound was frankly bad and often spoiled the whole impression. Other electronics next to these bulks of the acoustic system could not stand it, and the magnetic field created by the speakers had a negative effect on the person. And yet, it was the S-90s that were ideally able to create surround sound in an ordinary apartment of a standard panel house. In general, there were no special claims to the sound.

Installation

The shortcomings that the Soviet S-90 speakers had did not stop the music lovers of all Russia. They remained for several decades a speaker system from the category of the most massive. Many thousands of forum pages are dedicated to them today. This is one of the most striking symbols of a bygone era, which also possessed reliability and durability, which modern gadgets do not even have in sight. The C-90 columns had impressive dimensions (36 x 71 x 28.5 cm), so they required correct installation, which is not always combined with the possibilities.

The apartments were quite cramped (and even now the conditions are the same), and therefore you could see the speakers half a meter from the listener. While the ideal way for the best sound is to put them on a pedestal just half a meter high and keep a distance of at least two meters from the listener's ear. A rare room has such advantages, the required area is often not enough, and therefore they listened to the real sound that this equipment was capable of, except perhaps the neighbors.

Appearance

At the S-90 column, the body is made simply and soundly - a non-separable rectangular box made of chipboard, finished with high-quality veneer from valuable wood. The wall thickness is 16mm and the front panel is made from 22mm aircraft plywood. The joints of the walls and inner sides are reinforced with special elements that increase the rigidity and strength of the hull.

Made on the heads decorative frames black, stamped from aluminum sheet. They are also protected by a metal mesh. On the front panel, the mid-range head is insulated inside with a cone-shaped plastic casing, the low-frequency head is located along the vertical axis. At the bottom of the dispenser is a plastic overlay panel with a nameplate. There is also a hole 100 x 80 millimeters - this is the output of the phase inverter. The frequency response (AFC) is displayed on the nameplate, all curves correspond to the positions of the regulators. There is also the actual name of the speaker system and the brand name. The above-described frame with fabric is attached to the front panel with bushings. On the back wall below - a block with terminals.

Inside

The internal volume is filled with a sound absorber made of technical cotton wool covered with gauze. Thus, the effect of sound pressure on the frequency response is reduced and a better sounding of the speaker is achieved by eliminating resonances in the internal volume. Inside the case there are electric filters on the board that separate the bands of the speaker system. The kit also included four plastic legs designed for mounting on the base of the case, as well as a decorative removable frame with knitted fabric, which adds acoustic transparency.

A rare speaker system of those times has such qualities as the S-90 speakers - the sound power is just off scale! But at close to the maximum volume, low frequencies become illegible and booming, and the tops begin to click - this salient feature high-frequency heads 6GDV-1-16. A little later, when similar products began to go on sale - Amfiton 35AC-018, Orbita 35AC-016 and others, a different head was used. Sometimes analogues of this speaker system gave a deeper and more balanced sound than original speakers S-90.

S-90 line

All modifications of the S-90 and even all its analogues were certainly aimed at using cassettes. The high-frequency head reproduces the sound quite well in the upper frequency range thanks to the cassette deck and the Soviet amplifier. But if the lower and middle parts of the high-frequency range are reproduced just fine, then the very top differs from them, therefore it receives criticism for supposedly blockages in the frequency response and unevenness.

And the Orbita column of the S-90 line of the Moscow plant turned out to be a truly worthy alternative to the Riga Radio Engineering. This modification with a similar set of acoustic heads differed only in the presence of a two-pipe phase inverter at the very bottom of the case. As a result, the bass became lower and thicker. However, problems with hum and illegibility remained at high power, and the upper frequencies clattered in the same way as in the Radio Engineering S-90.

Manual upgrade

Many music lovers nevertheless realized their own dream: they bought the legendary S-90 speakers and began to refine them with a “file”. The decision is budgetary, fascinating, and then the sound is the envy of everyone. Outside, over the past thirty years, the columns have, of course, lost their former chic in almost one hundred percent of cases, but the main thing here is that no one digs inside. You need to start working by enriching your arsenal with tools. You will need a basic set of screwdrivers, pliers, a soldering iron. The first step is to remove the front panel, for which you need to unscrew a dozen or two different screws.

When disassembling, it is imperative to check whether the filling corresponds to the passport. To have 10GD-35 at high frequencies, 15GD-11A at medium frequencies, and 35GD at low frequencies, for example (well, or whatever is stated in the passport). Speakers are most often damaged, since it is possible to ruin equipment within one day, and even more so in thirty years. For example, a lot of furniture rearrangements and moves could happen. Most likely something is damaged. For example, a bass speaker. His resuscitation will require additional work. You need to rewind the coil. In principle, it is not so difficult if you know some of the subtleties and at least a few times earlier encounter the rewinding process. After winding, centering and drying, the sound of the speaker will be perfect - all extraneous overtones will disappear.

Domes

Speakers S-90, as everyone knows, most often upset the sound of high frequencies - with overtones. Yes, and at medium frequencies there is often no sonority. Craftsmen recommend basically the same thing: replace the midrange, treble and dampen the case. But it is better not to look for easy ways. Just the speakers are covered with plastic domes. This material is completely inappropriate.

Silk domes will remove overtones and make the sound more transparent. Therefore, the speakers can be safely replaced. While one speaker is being upgraded, it is imperative to test the sound and compare it with the one that the upgrade is just waiting for, that is, with the original. Then it becomes absolutely clear whether to leave the alteration or return everything as it was. The main thing is that the owner of the speakers and golden hands also has a good hearing.

Wiring and housing

To improve the sound of low frequencies, you need to refine the cabinet. Down with cotton-gauze mattresses! Stores sell inexpensive batting that makes an excellent filling pad. And for just over a hundred rubles! All this can be done quickly and without any effort: the width of the batting is two meters, enough for two columns, but you need a furniture stapler or a friend who has one. Before installation, just in case, it is better to change all the wiring, remove the switches. Cut out the batting in two layers and boldly sheathe the body.

The phase inverter pipe is placed on the sealant, and after that it is also covered with batting. Not much work directly with the filter either. The switches will never be needed, so they can be removed, like all unnecessary elements from the board. All these thirty-year-old thin wires should be replaced with normal copper wires on all connections. Further, the filter, freed from all unnecessary, must be carefully installed in the case and closed with a batting. The entire midrange box on the outside should also go under the material mentioned above.

Results

Judging by the reviews of home craftsmen, such simple improvements have changed the sound of equipment for the better, simply unspeakably. The bass became clear, the top - transparent, light. After replacing the speaker at mid frequencies, vocals sounded completely different.

Manufacturer: PO "Radio engineering", Riga.

Purpose and scope : For high-quality reproduction of music and speech programs in stationary domestic environments. The S-90 acoustic system, developed in 1975, is the first domestic system that meets the requirements of international documents for Hi-Fi category equipment. S-90B a later "S90" model featuring extended frequency response, the introduction of loudspeaker electrical overload indication, and a new look. The recommended power of a high-quality household amplifier is 20 - 90 watts.Manual on disk.

Characteristics

3-way tower speaker with bass reflex

Frequency response: 25 (-14 dB) - 25000 Hz

Frequency response unevenness in the range of 100 - 8000 Hz: ±4 dB

Sensitivity: 89 dB (0.56 Pa/√W)

Directionality at angles of 25 ± 5 ° in the horizontal plane and 7 ± 2.5 ° in the vertical plane, from the frequency response measured along the speaker acoustic axis:

vertical: ±3°

Horizontal: ±4°

Harmonic distortion speakers at a sound pressure level of 90 dB at frequencies:

250 - 1000 Hz: 2%

1000 - 2000 Hz: 1.5%

2000 - 6300 Hz: 1%

Resistance: 8 ohm

Minimum impedance value: 7.6 ohms

Rated power: 35W

Limiting (passport) power: 90 W

Short-term power: 600W

Installed Speakers:

LF:

MF:

HF:

Dimensions (HxWxD): 710x360x285 mm

Weight: 23 kg

Design

The case is made in the form of a rectangular non-separable box made of chipboard, veneered with fine wood veneer. Wall thickness 16 mm, front panel - plywood 22 mm thick. Elements are installed at the joints of the body walls from the inside, which increase the strength and rigidity of the body.

The heads are framed by two decorative overlays, made of plastic, painted "under the metal" or black. One overlay frames the midrange and treble, as well as the upper half of the front panel, the other - the bass head and the lower half of the speaker front panel. The heads are protected by metal meshes. Each of the overlays is fixed with six decorative screws. The midrange head on the inside is isolated from the total body volume by a special plastic casing in the shape of a truncated cone. Heads LF, MF and HF are located on the front panel along the vertical axis. The nameplate at the top of the speaker shows the frequency response curve and gives the name of the speaker. In the right corner of the front panel there are indicators of loudspeaker overload by channels, and in the lower part there is a rectangular phase inverter hole, 108x35 mm in size and with a tuning frequency of 25 Hz. On the rear wall of the speakers, there is a nameplate with the main characteristics and a block with clamps for connecting a connecting cord, as well as sound pressure level controls at medium and high frequencies.

The internal volume of the speaker is 45 liters. To reduce the impact on the frequency response of sound pressure and the sound quality of the AC resonances of the internal volume of the case, it is filled with a sound absorber, which is mats of technical wool covered with gauze.

Inside the case, on one board, there are electrical filters that provide separation of the AC bands. Crossover frequencies between LF/MF - 750 Hz (±50 Hz), between MF/HF - 5000 Hz (±500 Hz). In the design of the filters and the overload indication unit, resistors of the VS, MLT, SP3-38B, S5-35I, PPB types, capacitors of the MBGO-2, K50-12, K75-11 types and inductors on plastic molded frames were used.