Manufacturer: PA "Radio Engineering", Riga.
Purpose and scope : for high-quality reproduction of music and speech programs in stationary living conditions. The S-90 acoustic system, developed in 1975, is the first domestic system, meeting the requirements of international documents for Hi-Fi equipment. S-90 B the later model "S90", characterized by an expanded range of reproduced frequencies, the introduction of an indication of electrical overload of the loudspeakers and a new appearance. The recommended power of a high-quality household amplifier is 20 - 90 W.Instructions for Use on disk.
Characteristics
3-way floorstanding speaker with bass reflex
Frequency range: 25 (-14 dB) – 25000 Hz
Frequency response unevenness in the range 100 - 8000 Hz: ±4 dB
Sensitivity: 89 dB (0.56 Pa/√W)
Directivity at angles of 25±5° in the horizontal plane and 7±2.5° in the vertical plane, from the frequency response measured along the acoustic axis of the speaker:
in the vertical plane: ±3°
Horizontal: ±4°
Harmonic distortion of 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 ohms
Minimum impedance value: 7.6 ohms
Rated power: 35W
Maximum (nameplate) power: 90 W
Short-term power: 600 W
Installed speakers:
LF:
MF:
HF:
Dimensions (HxWxD): 710x360x285 mm
Weight: 23 kg
Design
The body is made in the form of a rectangular non-separable box made of chipboard, veneered with valuable wood veneer. The wall thickness is 16 mm, the front panel is plywood 22 mm thick. At the joints of the housing walls, elements are installed on the inside that increase the strength and rigidity of the housing.
The heads are framed by two decorative overlays, made of plastic, painted “metal” or black. One cover frames the midrange and tweeter, as well as the upper half of the front panel, the other – the woofer head and the lower half of the front panel of the speakers. The heads are protected by metal mesh. Each of the overlays is secured with six decorative screws. The midrange head is isolated on the inside from the total volume of the housing by a special plastic casing in the shape of a truncated cone. The LF, MF and HF heads 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 speaker overload indicators by channel, and in the lower part there is a rectangular bass reflex hole, 108x35 mm in size and tuning frequency of 25 Hz. On the rear wall of the speaker there is a nameplate with the main characteristics and a block with clamps for connecting the connecting cord, as well as sound pressure level controls for 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 speaker resonances of the internal volume of the housing, 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 ensure separation of the speaker bands. The crossover frequencies between LF/MF are 750 Hz (±50 Hz), between MF/HF - 5000 Hz (±500 Hz). The design of the filters and the overload indication unit uses resistors such as BC, MLT, SP3-38B, S5-35I, PPB, capacitors such as MBGO-2, K50-12, K75-11 and inductors on plastic cast frames.
This page shows diagrams of Radiotehnika class S90 speaker systems (35AC-212, S90, S90B, S90D, S90F, S-90E), detailed description, speaker parameters, photographs.
Quite high-quality acoustics from Soviet times, after minor modifications and restoration, I can say with confidence that it will give a head start to many modern acoustic systems.
If you have similar ones lying around or bought them somewhere cheap, then put them in order and they will delight you for a long time with powerful bass, rich mid and high frequencies in musical works of any style and direction, in general I RECOMMEND!!!
Acoustic system S-90 (first model)
Rice. 1. Appearance speakers Radiotehnika S-90.
The speaker system has two step playback level controls separately for mid and high frequencies in the ranges from 500 to 5000 Hz and from 5 to 20 kHz, respectively.
Both regulators have three fixed positions: “0”, “-3dB” and “-6 dB”. In position "0", the signal from the crossover filter is supplied to the corresponding head directly. In the “-3 dB” and “-6 dB” positions, the signal is weakened relative to the “0” position by 1.4 and 2 times, respectively.
With the appropriate spectral composition of the program, switching the knob changes the timbre coloring of the sound.
Passport technical specifications S-90:
Rice. 2. Schematic diagram acoustic speakers S90 35AC-212.
Acoustic system S-90 35AC-1
Rice. 3. Speaker system Radiotekhnika S-90 35AC-1, appearance, photo.
Rice. 4. Schematic diagram of the Radiotehnika S90 35AC-1 speaker.
Speaker system Radiotehnika S-90B
Rice. 5. Appearance of speaker systems Radiotekhnika S-90B.
Speaker system S-90D
Rice. 6. Appearance of acoustic speakers Radiotehnika S-90D.
The speakers have an indication of speaker head overload. 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 within the range from 0 to minus 6 dB.
There is also a model of the speaker system "S-100D", it uses a mid-frequency head 30 GDS-3 with MAHID magnetic fluid, which allows you to increase the rated power of the speaker system to 100 W. Otherwise, the designs of "S-90D" and "S-100D" are similar.
To operate, 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 W.
If the OVERLOAD indicators start to light up when the speaker is operating, then you should reduce the level of the input signal supplied to it (by using the volume control in the amplifier to which the speaker is connected).
S-90D technical specifications:
The picture below shows
Music lovers constantly start debates about which speaker system to choose for comfortable listening to music at home. And this is no accident: the entire contingent was divided into two camps. The first believe that it is worth shelling out a tidy sum to buy a cool Hi-Fi (or better yet, Hi-End) system in order to be happy and forget about headaches about this topic for the rest of your life. But there are also those who are not ready to give up their entire life’s savings for expensive acoustics (instead of the required car or apartment), which is why they think the best option purchasing simpler equipment or refining the good old classics to good sound.
In this article we will talk about one of the most popular audio systems produced during the USSR, which could not leave any of its owners indifferent. The S90 speakers, the technical characteristics of which can excite consciousness to this day, have become one of the highest achievements of the Soviet company Radiotekhnika.
Speaker models
The very first thing worth mentioning is the real and full name of the speaker model - 35AC-012. An important factor is that this acoustics was produced in several variations. The most popular of them are S90 and S90B. There were also S90i, S90D and S90f models, but they were not widely used and are now almost unheard of.
The model with the postfix “B” differed from the usual “nineties” in a wider range of reproduced frequencies. Another significant difference was the introduction of an electrical overload indicator for the speakers. The recommended high-quality amplifier power for these speakers is in the range of 20 to 90 watts. It is also worth noting that Radiotekhnika S90, S90B (and other modifications) were the first models of speaker systems that met international requirements for Hi-Fi equipment.
Design
The case in which the S90 speakers are enclosed is, in fact, a non-demountable rectangular box made of veneered wood. The thickness of the speaker walls reaches 16 mm, the front panel is made of 22 mm thick plywood. The internal joints of the cabinet walls are connected by special elements that increase the rigidity and strength of the structure, but do not interfere with high-quality sound.
If you look at the device from the front, the speakers are arranged in the following order (from top to bottom): tweeter, midrange speaker and woofer. Also on the front panel of the S90 speaker you can see the frequency response (amplitude-frequency response) graph and the bass reflex hole. While the frequency response is located at the top or bottom (depending on the acoustic model), the bass reflex is always located at the bottom. This was done for reasons of proper design for better sound and giving the speakers good bass.
Speakers S90: characteristics
If we take the regular S90 as an example, they have dynamic direct radiation heads installed. More precisely, a high-frequency head 10GD-35, a mid-frequency head 15GD-11A and a low-frequency head 30GD-2 (in later models - 75GDN-1-4).
Equipped with two step playback level controls to adjust the midrange and treble in the ranges from 500 to 5000 Hz and from 5 to 20 kHz. Each regulator moves in three fixed positions. In position “0” there is no obstacle for the signal from the crossover filter, and it is fed directly to the corresponding head. When using the “-3 dB” and “-6 dB” positions, the signal is attenuated by 1.4 and 2 times, respectively, relative to the “0” position. By switching the selected control, you can change the timbre of the sound.
The rated power of the S90 speakers is 90 Watts, while the nominal power is 35 Watts. The nominal electrical resistance of this speaker system is 4 ohms, and the range of frequencies available for playback ranges from 31.5 Hz to 20 kHz. The nominal sound pressure of the S90 is 1.2 Pa. I would like to note the rather impressive dimensions of one column - 71.0 x 36.0 x 28.5 cm, and the total weight of the entire system reaches 30 kg.
Speaker circuit and connection to the sound source
In order to understand whether it is worthwhile to modify any speaker system, you need to study all the data and aspects of the equipment. Below is electrical diagram speakers S90. Anyone, even a novice radio amateur, can understand it; you just need to have at least basic knowledge.
Another important point is the correct connection of the speaker system. After all, if something goes wrong, even during connection you can, without meaning to, damage the equipment. You don't need to be a professional to figure out how to connect S90 speakers. The main thing is to have at least 20 watts with the amplifier (in this case, most likely, the sound will not be loud enough for large rooms), but not more than 90 watts. If the amplifier's permissible power value is exceeded, the user risks being left without acoustics due to its breakdown. To connect, you will need regular speaker wires, which must be connected to the terminals on each speaker and amplifier. The main condition for connection is compliance with polarity.
Revision 35AS-012
As it becomes clear from the description above, it itself has good technical characteristics and is capable of “rocking up” even small public spaces. But for home use, the most sophisticated music lover will prefer to modify the S90 speakers with his own hands. And all because the acoustic systems of the Radiotekhnika company, assembled more than twenty (or even thirty) years ago, did not already have high build quality and the materials used in those years.
Parsing
In the event that the acoustics were purchased in used condition and are currently well-worn by life, it is worth paying attention to the appearance. To do this, you need to disassemble the S90 speakers, first placing them on their “back”.
When removing the speakers, you need to take into account that the tweeter and midrange heads are attached to the housing using the same screws as the linings. The woofer is attached separately, and you need to be as careful as possible not to damage it when unscrewing it.
The HF/MF controls are much easier to dismantle than they seem. All you need to do is carefully remove the decorative plugs that are located in the center of each regulator. After this, using a screwdriver, you need to unscrew the screw that is revealed to the eye and remove the regulator handle itself. The plastic lining must be carefully lifted on both sides using flat objects and removed, and the four screws remaining under it must be unscrewed. Then you can push the S90 inside the speaker, not forgetting to unsolder it from the filter.
The cotton wool bags located inside the case must be removed. Again, if the previous owner of the speakers did not forget to return them to their place in case of disassembly.
You should first unsolder the panel with filters from the output on the back side of the speaker, and then you need to dismantle it by unscrewing the screws. Now you can remove the panel with the terminals attached to it.
Appearance and body
If the grilles and decorative covers of the speakers are “tired,” then it is worth straightening them and painting them, having previously sanded and degreased them. This will give the speakers a fresh look. The body of the S90 speaker becomes loose over time and can be strengthened if desired. This will result in a better sounding woofer.
This can be done in various ways, including installing spacers and additional corners inside. It is also necessary to pay attention to sealing all joints and seams using conventional plumbing sealant. In addition, you can glue the inner walls of the case with foam rubber (except for the front), which will increase the volume of the latter.
Terminals and filter
Knowledgeable radio amateurs advise replacing the standard speaker terminals with universal type terminals with gold-plated connectors. The installation location must be lubricated with sealant and the panel with terminals must be put in place.
Considerable attention should be paid to the sound filter. If it was attached to the body with metal screws, then the filter settings will be lost. There are cases where the filter was assembled on a metal plate. This can be corrected by transferring all nodes to a plywood panel. The circuit of the filter itself may have been changed at the manufacturer due to different parameters of the speakers, so you should make sure that everything is assembled in accordance with GOST. If there are jumpers in the filter, then they must be removed and replaced, for example, with an oxygen-free copper cable with a cross-sectional area of 4 mm 2. It is worth removing the attenuator from the circuit, since it simply distorts the sound, and replacing the wires used to connect the speakers to the filter.
For low-frequency speakers, a wire with a cross-section of 4 mm 2 is suitable, for mid-range speakers - with an area of 2.5 mm 2, for high-frequency speakers - with an area of 2 mm 2. After these simple steps, the filter must be returned to its place and covered with foam rubber.
Speakers and other "trifles"
New seals should be cut for the speakers. This can be done using cheap or simply outdated rugs. computer mouse. This is the simplest option. After this, it is worth returning them to their seats and installing decorative overlays and nets.
Before installing the regulators in place, you will have to remove all resistance from them. When installing them in place, it is imperative to use sealant, as when installing a bass reflex.
Through such simple manipulations, the S90 speakers acquire new life. The sound quality becomes an order of magnitude higher, despite the low costs. As a result, we can say that if you don’t have the money for expensive 2.0 format acoustics, you can use a similar option and become the happy owner of the time-tested Radiotekhnika S90 speaker. If it happens that only half of the speakers are available, do not be upset. After all, it is noteworthy that the S90 speaker, a photo of which can be found on almost any website of acoustics enthusiasts from the times of the USSR, can work alone and give good results.
Whatever the snobs say, the Soviets were truly high level. Even now they can bypass many modern beepers. And after appropriate modifications, even budget speaker systems from Yamaha cannot compare with them. And now we will look at the legendary Radiotehnika S90. This is a symbol Even abroad they noted the high quality of this (at one time). Therefore, it makes sense to consider these columns. Moreover, many people still use them to this day.
A little history
Radiotehnika S90 speakers were first released in the early eighties of the last century. They were produced by a plant located in Latvia, which became an additional incentive for citizens to buy them. Despite the rather high price, the speakers sold like hot cakes. People saved for a long time, did not eat enough, hiccupped them wherever possible. They even purchased used speaker systems. Just to decorate your closets with “Radio Engineering”.
Nowadays, many audiophiles are still chasing this speaker system. Speakers "Radio Engineering" are the dream of every connoisseur of high-quality sound. But now they can only be purchased on the secondary market. And it’s far from a fact that their condition will be acceptable (affect However, this acoustic system can give a head start to many modern speakers. And after appropriate modifications, it completely turns into Hi-End class acoustics. And this is a completely different level.
Appearance and Design
Looks impressive from Radiotekhnika. These are very large speakers. Each of them weighs about 15-20 kilograms. This is not to mention the fact that carrying them is not very convenient due to the bulky and bulky case. The front panel (like the entire body) is covered with veneer. There are several color combinations. Speakers are covered metal mesh. Only the tweeter is not covered with protection. This is, of course, good, but it does not have the best effect on the acoustic properties of the speakers. However, the design is quite acceptable. Much better than other speakers of “clumsy” Soviet production.
WITH right side From the mid-frequency and high-frequency speakers there are two operating mode switches. It is unknown why they were placed here. A normal amplifier itself is capable of switching modes. And the job of speakers is to reproduce sound correctly. Nevertheless, Radiotehnika S90 has such switches. But during the finalization process they can be removed, because they have a very negative effect on the overall sound quality. But for those who appreciate retro and antiques, such proposals will seem blasphemous.
Specifications
So let's get down to the hard numbers. Normal speaker power is 35 watts. But these beauties can easily give out 90. That is why they were called “the neighbors’ nightmare.” However, to fully exploit them, stereo amplifiers of appropriate power are required. Only then will this speaker system really sound. The frequency range starts at 20 hertz and ends at 25,000 hertz. This wide range allows the speakers to reproduce almost all instruments quite reliably. The frequency response is quite acceptable for an acoustic system of this level. You can't expect any miracles from her. But the sound is quite decent.
Now comes the fun part - the woofer. This is the legendary "Din 75 GD". The thing is, of course, good, but it does not produce perfectly reliable bass. If the low-frequency speaker is at least something of itself, then the mid-frequency and low-frequency drivers, although they cope with their task, can not be called “kosher”. Ordinary paper bubbles. It would be much better to replace them with Kevlar or silk canopies during refurbishment. That's when the big speakers will start sounding. And it’s better to rewind the woofer, since in used speakers it often burns out due to “super-mega bass”.
Sound quality
As mentioned above, Radiotekhnika speakers with standard components cannot boast of very clean and correct sound. But the quality is enough for not very demanding listeners. The acoustic system copes well with instrumental music (light rock, jazz, blues), and the electronic system also works well. But heavy and other subgenres of great and terrible metal - not so much. That is, the speakers reproduce it as expected, but the woofer jerks so much that it could easily break. Especially when listening to those groups that often abuse the cardan on the kick drum.
The classics also go well. This is probably the only genre that the Radiotehnika S90 copes with very well. All instruments sound crystal clear. Nothing gets ahead of itself. Even audiophiles may enjoy listening to classics on these speakers. However, it is impossible to call this speaker system a Hi-End item. To achieve this level, the speakers will have to be modified. As standard, this is an average but confident Hi-Fi. A to the Soviet man nothing more was needed.
Amplifiers for S90
In order for passive acoustics to sound good, high-quality stereo amplifiers are also required. It should be noted that the “nineties” can only be driven and fully revealed by a very powerful amplifier. The Soviet vehicles "Brig" and "Odyssey" will cope with such work perfectly. These monsters are capable of getting everything out of the speakers. Amphiton U-001 will also do a good job. Just don’t even think about connecting this speaker system to the Vega 50U. The amplifier will immediately refuse to work even at minimum volume.
The ideal option for this speaker system is the Radiotekhnika amplifier. They were produced in huge quantities, with varying power and resistance. Therefore, finding such a thing on the secondary market is not a problem. There are more than enough amplifiers of this type suitable in terms of power. You can, of course, puzzle yourself and connect these speakers to a completely modern receiver like Yamaha. But then such a kit will go far beyond the “budget” scope. And such a decision is not worth the candle. It's like putting a Porsche engine into a Zaporozhets. It's possible, but there's no point.
Price S90
Now let's look at the most interesting quality of Radiotehnika S90. The price on the secondary market depends on the “kill” of the kit and its originality. Speakers in standard configuration and in decent condition will cost from 1000 to 2000 rubles. Depending on how good they look. Speakers with a whole internal system cost almost the same. You can even find ones that are barely used. It all depends on the seller himself and the level of awareness of the buyer. Speakers modified according to all the rules will cost more, since this is an acoustic system of a completely different class. They will cost about 3,000 rubles.
The Radiotekhnika amplifier will also cost about the same amount. Monsters like the Brig or Odyssey in perfect condition will cost around 15,000 rubles. But the problem is that finding them is almost impossible. In total, the approximate cost of the complete set will be approximately 6,000 rubles. Much better than an obscure Chinese speaker system for the same money. However, this is an approximate cost. It may vary depending on the degree of modification of the speaker system and its condition. But it still turns out to be much more profitable. And the sound quality will be at the same level.
Positive feedback from owners
Now let's look at the reviews about the Radiotehnika S90 speaker system. The amplifier is separate topic, so we will not consider it here. So what will the owners say? Positive and negative reviews They are neck and neck over these columns. Competent audiophiles have long since finalized their “nineties” and therefore their reviews are laudatory panegyrics addressed to Soviet speakers. There is clear sound, clearly defined bass, wide range, versatility (for all genres) with some equalizer adjustment. Also an important advantage for many was the completely wooden body. And the power of these speakers is the talk of the town. Everyone noted this quality.
Negative reviews from owners
However, there are also snobs who are not satisfied with the sound quality of this speaker system. They note insufficient definition of mid and high frequencies (and this is true). The case, after so many years of use, is simply rattling. The subwoofer thumps out of place. But, comrades, any thing needs to be monitored and timely prevention carried out. This also applies to speakers. After the appropriate procedures, they will sound completely different. Dissatisfied S90 owners - take note!
Conclusion
Radiotehnika S90 is one of the most preferred budget options. It copes with its responsibilities much better than any modern acoustics from China, is highly customizable and can provide Hi-End class sound. What else does a music lover need to be happy?
27120
Modernization of S-90 speakers by replacing standard cabinets with labyrinthine design of bass speakers
Upgrade of the S-90 labyrinth design by stuffing the corners with cotton wool and sticking them on the inner surface of the wool blanket
At first, only the frontal knees of the labyrinth were covered with wool, then the side surfaces too
Ready labyrinth S-90 covered with wool internal surfaces
Remaking the most famous speakers of the USSR Radiotekhnika S-90
Alexander Rogozhin came up with the know-how of how to convert the Radiotekhnika S-90 speakers, most well known to most Russian-speaking people, into labyrinthine housings. The article is devoted to the most widespread and for more than 20 years considered the standard of acoustics Soviet period, which in its first generation was called 35AC-1. And Rogozhin proposes to make speakers from 35AC-1 (Radio Engineering S-90) with the name “Cheap, loud and super-bass”!
Ode to speakers Radiotekhnika S-90 (35AC-1)
There is no person who speaks Russian, Ukrainian, Belarusian, who at least once in his life has not heard the famous Soviet Radiotekhnika S-90 speakers, or has not had one of their modifications produced in the mezzanine, in the closet, at home or on the hacienda more than 30 years. You can think whatever you want about their sound, appearance, rubber speakers, but in fact these are the MOST common “People’s” speakers in the vast expanses of the former USSR. Even now, tens of thousands of them work in the systems of music lovers, who feel sorry to throw them away because Compared to the branded “remake” they play very, very well.
If a person is faced with a choice on which speakers to listen to music on: with bass, loudly, and for ridiculous money, then despite all the disadvantages of the Radio Engineering S-90, they have practically no competitors, and even less so before. In the late USSR, in addition to S-90 speakers, of course, “clones” appeared, taken from the best foreign samples, for example, Electronics 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 basically impossible to get three full-fledged bands with the same power as the S-90, a 10-inch woofer and almost nothing from any other speakers. This is even more relevant now.
Tens of thousands of these speakers still work in the rooms of young and not so young 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 Radiotekhnika 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.
And yet we all love to listen to music, it happens to everyone good mood, when you want to turn it on “to the 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 UUUH! And low frequencies are actually a very delicate thing; in order to sound adequately and make an impression, they require large speakers, cabinets and power. But even with all this (in large speakers like the S-90), the bass often turns out to be buzzy, drawn out and indistinct, and does not give us the “buzz” that it is supposed to give. We quickly get tired of such bass and start turning the tone control knobs or switching the equalizer modes on the receiver. And instead of getting pleasure, you get annoyed and think about the imperfections of this mortal world... Almost all music lovers and owners of these acoustics, in particular, have found themselves in this situation more than once.
Low Frequency Problems S-90
The reason that over the past 30 years, owners of the Radiotekhnika 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 with the S-90 speakers, confirmed by repeated research by specialists, is an error made when designing the low-frequency design of the 30GD-2 speaker. Having entered the series, an error led to the fact that the potential for high-quality reproduction originally inherent in the Radiotekhnika S-90 model and its modifications low frequencies, is not realized 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 until today They are trying to improve the low frequencies of these speakers by witchcraft with filters, altering the bass reflex pipes, strengthening the original housings and filling them with whatever comes their way.
Dear music lovers! I urge you to stop doing nonsense, because... this is absolutely useless... The S-90 speakers from the factory have a housing with a volume of only 45 liters - NOT corresponding to the optimal operating mode of the 30GD-2, 75GDN1-4 speaker installed in it. You can even trim it with the roots of rare species and cover it with porous rubber on all sides - it will still NOT work correctly.
That is, the question of radically improving the performance of these speakers at low frequencies, no matter how regrettable it may be, is that the question of replacing the housing arises in full force.
The task is somewhat complicated by the fact that over 30 years a huge number of modifications of the 35AC-1 speakers with 30GD2/75GDN1-4 (8) low-frequency speakers have been released, which have a wide range of parameters. In the new enclosures, this problem has been largely resolved and allows speakers from the earliest releases to the latest to feel correct. The setup of new enclosures is “stretched” and allows you NOT to specifically select low-frequency speakers.
Mid Frequency ProblemsS-90
Almost all owners of s-90 speakers note unpleasant overtones and greater unevenness of output at mid frequencies, which become especially noticeable at medium and high volumes. All grandiose projects to remake filters by installing expensive imported capacitors, 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 mid frequencies is not the 15GD-11 speaker at all, but its acoustic design. This “glass” covering the midrange head from behind has a tiny volume and is the second mistake made by the engineers who designed the S-90 speakers. The “glass” of the mid-frequency head 15GD-11 (20GDS...) has everything wrong, from the volume and configuration to the internal design. When replacing the housing of the s90 speakers with the correct one from the point of view of the design of the woofer, the mid-frequency speaker should also be designed accordingly.
Of course, replacing the “minuscule” standard glass with an acoustic design that is optimal in 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 you can get
As a result, the updated S-90 speakers will sound radically different not only at low, but also at medium frequencies. There are a large number of attempts on the Internet to remake S-90 speakers with the goal of “deceiving everyone” and turning them into studio monitors. Attempts concern everything except replacing the main “weak point” - the body, and most often turn out to be failures. While keeping the S-90 speaker cabinets unchanged, 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 suggest leaving the original set of S-90 speakers untouched. Their value lies in the minimum budget and, no matter how clever you look, their performance has been proven over decades of operation in the harshest conditions.
What these speakers have that can be fundamentally improved is to “get the most out of their speakers.” To do this, you need to make an acoustically correct housing for the original set of speakers and filters. As a result, you can reach a fundamentally new level of sound quality from these speakers without spoiling anything.
As a bonus, you don’t have to throw away the old cases and, if necessary, the “stock” S-90s can be put back together and sold to some lover of authentic speakers made in the USSR.
Problems with native boxesS-90
- The wrong amount of low-frequency design does not provide the required level of pressure on the low frequencies;
- Non-optimal bass reflex tuning frequency leads to uneven bass response and poor bass quality;
- The type of low-frequency design “bass reflex” in combination with a “tight” speaker on a rubber surround leads to an extended and monotonous “hum” at low frequencies, instead of a clear impact bass;
- Phase-inverted acoustic design leads to significant unevenness of sound pressure at low frequencies in the room, and places demands on obtaining high power from the amplifier;
- The weak walls of the S-90 speaker boxes lead to a loss of efficiency at low frequencies and produce noticeable overtones when operating at high volumes;
- Poor sealing of the boxes prevents even the low-frequency design that the S-90 speakers have in the stock version from working;
- The extremely small volume of the cap of the mid-frequency head 15GD11 (20GDS-) leads to “squeezing” of the mid-frequency dynamics;
- Non-optimal damping of a small-volume midrange box leads to noticeable overtones and “nasality” in the midrange;
- The shape and dimensions of the S-90 speaker cabinets in the stock version require their installation on furniture, which leads to a “wobbly position” of the speakers, resonance of the furniture at high volumes and, ultimately, to deterioration in the sound of low frequencies;
- The “low-profile” shape of the speaker housing requires installation on specialized stands for acoustics, which ultimately increases the cost of the system. Installing the 35AC-1 speakers on the floor leads to a lack of high frequencies and an incorrect scene.
Advantages of new buildings
- The design of the low-frequency head is a quarter-wave labyrinth with its radical advantages at low frequencies over a bass reflex (detailed description here);
- The optimally calculated frequency and quality factor of the quarter-wave resonator tuning provide a wide band and optimal level of low frequencies;
- The highest rigidity of the box gives the highest possible efficiency, clean, elastic and biting sound at low frequencies;
- The high-volume, hard-box midrange driver produces a lively, open midrange and clear vocals;
- The placement of the midrange and high-frequency speakers on the front panel, maintaining the distances to the cabinet walls according to the “golden ratio” principle, reduces diffraction phenomena on vocals and high frequencies and makes the sound much more comfortable;
- With the new enclosures, the acoustics transform into a classic floor-standing design with midrange and high-frequency speakers optimally positioned in height;
- The speakers have narrower and taller front panels than standard S-90s and do not require any stands. The appearance of the speakers is improved many times over.