How did it start

I had a dream for a long time - to buy the legendary S90 and modify them with a file to make a budget decision for the envy of everyone. For a long while monitoring various flea markets, I still bought on the same column 35AC-212 "Radio Engineering" S90 that was produced in 1981 (my peers;)).
The state on the outside is solid 4, inside the crooked paws no one picked. There was only one minus - the bass from one speaker was killed, which I was honestly informed about, well, I really didn’t like the fact that both woofers were painted with silver (it’s good that the paint is not deep, that is, the mass of the diffuser has not increased much).
For 1000 p. bought a set for creativity.
We will modify.
Oh, I feel strong controversy between supporters of the improvements in Soviet acoustics and supporters of burying it completely and without turning.
I apologize at once for the quality of the pictures, because at the time of completion, and now I do not have a digital dust box except a phone.

We climb inside

After listening, I decided to parse each column for compliance with the insides of the passports of the columns. As it turned out, the high frequencies are 10GD-35, midrange 15GD-11A, and the low frequency 35GD (something) I did not remember but with a rubber suspension that did not dry out.
The first thing I did was rewind the woofer.
The restoration of the speaker was not a problem for me because I was doing this very often in my youth for denyuzhku. Unfortunately, I didn’t have the right mandrel, but the trick was foolish and I went with the caliper in my pocket to the nearest construction store. As a mandrel, I bought a plumbing pipe that seemed to be about 20 rubles. I sawed it lengthwise (this is necessary since after winding it will be practically impossible to remove the coil from the mandrel otherwise).
Let's add another 20 minutes for winding and centering and a day for drying the speaker. Everything, the speaker began to play without extraneous overtones and just as untouched.

Let's start with the tweeters

After listening to the result and reading the great Internet, I began to think further how to make the sound even better. Basically, all types of improvements come down to replacing the HF, replacing the MF, and damping the chassis.
Treble really doesn't sound very good. There are unpleasant sounds on the HF and lack of ringing on the midrange. In the high-frequency link, speakers are used with domes made of some plastic / polyethylene. I put 10 W speakers with silk domes for comparison, the sound on the treble became much more transparent and the sounds that simply cut the ear disappeared. As a result, these rootless speakers about 500 r per pair remained in them. I bought them for a long time and the labeling on them is not readable, and I do not remember what was written on the price tag. You can use 10GDV speakers with silk domes.

I note that at first I made one speaker and compared the sound from the test discs with the sound from the original speaker. After listening, I decide to leave the alteration or return everything back. Everything was done on my favorite rumor, which seemed to never let me down.

Refinement of the body

Then I decided to do the bass, i.e. refinement of the body. Batting was bought for ridiculous money 38 rubles per meter in length and 2 meters wide. Just looking at the filters made, he listened to the advice to change all the wiring in the columns.
Dismantled all the speakers from the speakers. He took out the filter and switches. Wires can be safely cut as they are all the same for replacement.
Then he cut out the necessary piece of batting, took a furniture stapler from a friend, and began to sheathe them inside in 2 layers.


We put the phase inverter pipe on the sealant and we also tighten it with batting.


The next thing to do is refine the filter.

The filter circuit is simple.

I completely turned off the switches, since they are completely unnecessary. Unnecessary elements from the filter board are removed.
We change all the tiny wires in the filter to normal copper wire.
Here is the filter before the alteration.

And this is a copper wire of about 4 squares used for almost all connections.

As a result, redone with removed dividers and regulators, we

further install it in the case and close it with batting.
Also with batting we close the entire midrange box outside.

Midrange

In principle, after such improvements, the sound has changed for the better, the bass has become clearer, the higher frequencies have become “more transparent” and “lighter”, but I didn’t like the mids anyway, there was a lack of an upper middle. There wasn’t enough vocal ringing.
Having rummaged in the stocks I found two 4GD-8E in an excellent state. I put one speaker and compared the result for a long time. I liked the result. In one blues record I heard blows of brushes on the main drum. Before that, I did not distinguish between them.
But these speakers did not stand in acoustics for long.
After listening to the modified column for a week, I came to the conclusion that the sound began to bore me.
Probably all this is due to the fact that the 4GD-8E dynamic heads have a very high Q factor and in a closed box they have a very rugged frequency response. Unfortunately there is no normal microphone to take measurements. Yes, the midrange speakers were equipped with PAS made of foam covering the rear holes in the speakers. The midrange box itself is filled with fluffy “eye” cotton wool.

On the Internet, they often wrote about 5GDSH-5-4 and 6-GDSH-5, about the fact that after installing the PAS they perfectly give out the midrange. Walking through the nearby radio stores I bought a pair of 6-GDSH-5 4 Ohms for 110 p. As far as I understand, they are installed in household electronic equipment. I glued the windows in the diffuser holder with a thin batting and placed them instead of 15GD-11A, since the installation dimensions completely coincide. There is another way to refine the midrange speakers - impregnation of the suspension with mysterious guerrilla mixedwith the blood of the conductor of the orchestra with acetone and applying a thin layer to the back of the diffuser. But vesh, as I understand it, this is quite rare and in building mags they only shrug their hands. It would have taken an experiment because 110 r for a couple of new speakers is not a pity.

After all the operations, we fully collect the acoustics and enjoy the new sound. I tested the sound on a self-made amp of high fidelity Sukhoi (I'm afraid, true Hi-Fi connoisseurs will spew diarrhea in my direction) By the way, I also assembled the amp myself, with minor modifications in nutrition, and it has been playing for over ten years, but that's how it is in the same form of engineering sample. Connected it all to Sb Live! Playing flac special discs such as an audio doctor. And just wav and flac discs that are specifically recommended for testing the sound path.

Total

Costs 1000 r. acoustics itself
500 r tweeters
110 r midrange speakers
150 rubles batting, staples glue for screws and other trifles
Total 1760 r.
What did we get?

Here is such a nice acoustics.


Next is only my opinion and the opinion of my friends who have happened to her.
Another owner of flooring jbl does not remember the model, but they cost about 20,000 for Yamaha receivers alone, clearly agreed that after the completion of the S90 they replay its kit.
The sound completely suits me. Walking in different salons with acoustics and listening to her, I understand that such a sound is cheaper than 15 000 r. do not buy for one speaker.

Threat Now they play together with a simple amplifier Gumel and pre-amplifier BB Sukhoi. Connected all to the same sound SB Live! and works as a front to 4.0 sound for watching movies on the 37 "LCD panel. There is more than enough realism in disaster films. I don’t even think about adding a subwoofer.

PS All this is written by the sersad person who, well, cannot get into the hub And he will be very happy to invite him. In this case, he could continue further his articles and respond to all your comments.

By the way, his article is 1 article 2 .

UPD Thanks for invite!