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Modernization of the S-90 speakers by replacing standard cases with a labyrinth design of woofers
Labyrinth design upgrade S-90 by filling the 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 35AS-1. And Rogozhin proposes to make columns with the name "Cheap, loud and super-bass" out of 35AC-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 has 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. Getting three full-fledged bands from any other speakers with the same power as the S-90, a 10-inch woofer and almost for nothing was impossible in principle. 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 have not been 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 reproduction of low frequencies, which was originally incorporated in the Radio Engineering S-90 model and its modifications, is not realized even by 20-30% of the possible ones.
A huge number of owners of the S-90, 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 bass reflex 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 grandiose projects for reworking filters by installing expensive imported capacitors in them, replacing 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. A large number of attempts to remake S-90 speakers are presented on the Internet in order to "deceive everyone" and turn them into studio monitors. Attempts concern everything, but not the replacement of the main " weak spot”- hulls, and most often turn out to be failures. By keeping the S-90 speaker cabinets intact for fundamental change 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, it is possible to reach fundamentally new level the sound quality of these speakers without ruining 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 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 cabinets, 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. Appearance columns are improved many times over.
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 didn’t 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 a 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 simply evaporated: the howling of dogs disappeared somewhere, the knock 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 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. Loudspeakers Many people bought S-90s 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 negatively affected 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 Rus'. 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 are not even mentioned in modern gadgets. 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 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 influence of sound pressure on the frequency response is reduced and a better sounding of the column 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 clatter - this is a characteristic feature of the 6GDV-1-16 high-frequency heads. 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 analogs of this speaker system gave a deeper and more balanced sound than the original S-90 speakers.
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 column "Orbita" 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 upper frequencies clattered in exactly the same way as 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. Switches will never be needed, so they can be removed, like everyone else 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.
This page contains diagrams of Radiotehnika class S90 speaker systems (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 stepped 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 the "0" position, the signal from the crossover 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 controls 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 MAHID magnetic fluid, 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 you should reduce the level of the input signal supplied to it (by the volume control in the amplifier to which the speaker is connected).
Passport specifications S-90D:
The figure below shows
In that difficult period for Latvia and the world, a young engineer Roland Kerno worked at the enterprise, who later will create the first HI-FI class acoustic system in the USSR. It is believed that valuable experience in one of the best technical companies in wartime Europe significantly affected the thinking of the young engineer.
According to the memoirs of Likhnitsky, who in one of his publications mentioned a conversation with Kerno, it is known that he was involved in the creation of 300-mm loudspeakers and acoustic systems for radio receivers. Among other things, Likhnitsky mentioned that Roland Paulovich managed to find out several technological secrets related to the diffusers of German speakers (I would not be in a hurry to make the truth in the first instance from his article, given Likhnitsky's love for hoaxes).
Some biographical information
After receiving a certificate of secondary education, Roland entered the technical faculty of the Latvian state university. During the years of the occupation, as I already wrote, a graduate of the Riga University works at the Telefunken Geratewerk Riga enterprise, which then acquires the now well-known name Radiotehnika.
After the completion of the occupation, Roland Paulovich continues to work at the same enterprise as a Soviet engineer. At that time, the future creator of the S-90 can be called a man of his time without exaggeration. His engineering and design electro-acoustic solutions often anticipated the inventions of Western engineers. Unlike many Soviet developers, Kerno did not repeat the already created samples, but developed either a fundamentally new technique, or simply original and not inferior to foreign analogues.
In the early 1960s, Roland proposed using a multi-band frequency division design with a passive filter to achieve high fidelity. Such systems were practically not produced in the USSR, and in the West, mainly broadband ones were used. This is one of the many innovative solutions that will find its application in both Soviet and Western mass products already in the 70-80s.
Fundamental knowledge and bold technical solutions earned Kerno the unspoken title of the patriarch of Soviet electroacoustics. He quickly became one of the leading developers of audio equipment in the Orbita Design Bureau, which was part of the RRR Radiotehnika VEF software.
Prerequisites for the emergence of the S-90
As in the case of the first Hi-Fi amplifier, this speaker system could not appear on sheer enthusiasm. What was needed was the will of the leadership, and the so-called. planned need. This need arose in 1975. At the exhibition "Communication 1975" the radiogram "Victoria 003" and the electrophone "Allegro 002" were presented.
The presented samples were being prepared for release over the next 2 years. A problem arose with serial production: for the radio and the player there was no decent speaker system that could reveal their capabilities. The main criterion for the new speaker system was to be the power. In the terms of reference for developers, there was a nominal value of 35 W for each channel (i.e., about 100 W RMS).
The creation of such a system was entrusted to KB Orbita. Kerno took advantage of the situation and laid in technical task acoustics new requirements of the HI-FI standard. By that time, having received several patents for electro-acoustic inventions, Kerno decided to apply his developments to create speakers with high (by Soviet standards) fidelity of reproduction.
First steps - 35AC-1
As a result of an intense creative process, thanks to the intensive and well-coordinated work of the Orbita team under the leadership of Kerno, 35AS-1 were created in 1977. In fact, these are the same S-90s, only with a slightly different design. It was this speaker that became the first system that complied with the Hi-FI standard. The authors of the project were Kerno Roland Paulovich and Lasis Dzintars Arturovich.
