In a sense, historical events are divided into two stages: before Edison and after him, since his invention of the phonograph made it possible to hear and preserve the voices of people who lived "after." Yes, we can hear Mayakovsky reciting his poems, but we will never hear the voices of Pushkin and Lermontov. However, is it so?
Attempts to revive voices and sounds from the past were first undertaken back in the 60s. The first experiments were very simple: instead of a record, an ordinary clay pot was placed on the turntable disc, and a wooden hairpin about two centimeters long was fixed in the pickup instead of a needle. As soon as its tip touched the wall of the pot, a rather unpleasant rattling was heard in the dynamics.
These “frozen”, or, according to Munchausen, “frozen”, sounds from the past were imprinted during the formation of the pot on the potter's wheel, when the potter smoothed the edge of the product with the sharpened edge of a wooden plate.
In the next experiment, the motor that rotated the potter's wheel was placed on the frame and the craftsman began to shape the pot. After firing and installing it on a turntable, it was possible to clearly reproduce the hum of an electric motor.
In principle, a person's voice can also be "imprinted" on the pot, but it is very difficult to "revive" it. Nevertheless, we succeeded in doing this in the following experiment; a canvas was stretched over a wooden frame, a turntable was placed next to it and a record with a military march was started. Under the loud sounds of music, brush strokes were applied to the canvas. When they were then examined under magnification, they found that some of the strokes had transverse undulating irregularities. When, after the paint had dried, it was carefully passed over such a smear with a pickup needle (a small wooden spade-shaped hairpin), then the quiet sound of a military march was heard.
The same result was obtained with the human voice; it was possible to "sound" fragments of the conversation that took place at the moment when the artist applied strokes to the canvas. It is possible that with the improvement of the method, it will be possible to reproduce the voices of the people that the artist painted.
The technique described here inspired the author of these lines to a small invention, which he used in correspondence with his wife and friends. In the early 70s, tape recorders were mostly bulky, and how I wanted to hear a living voice in a letter! Recording a voice on a tape recorder, winding a piece of tape on a strip of cardboard and sending it by mail was no problem. And then how to reproduce the sound if there is no tape recorder nearby?
The answer to this question was the essence of the invention: a case from a toothbrush was removed from a pocket, the tape was laid on the table, the recipient evenly passed the tip of the case over it with the tip of the case, which contained an ordinary tape head, and a live human speech was heard from the small earpiece!
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But in any letter voices and sounds can be encrypted. Remember the experiment with paint strokes - the same effect occurs when a person moves a pen over paper; external sounds and your own voice make your hand vibrate and microscopic "notches" appear on the ink or pencil line.
In the 30s, the first Soviet systems for recording sound in films by engineers Tager and Shorin appeared. In one of them, the sound recorded by the photoelectric method looked like a continuous black line with transverse "notches" on the film.
So, in a movie camera equipped with this sound reproduction system, a blank film was loaded, the loop of which, through the guide rollers, was brought to the table in front of the experimenter. He held the ink pen motionless, and the tape moved, leaving a continuous line. The people standing nearby created a "sound background": they talked loudly, whistled, clapped their hands and even meowed.
Then the tape was reinserted into the movie camera and the sound was turned on for playback. Of course, I had to tinker with the signal amplifier, but the experiment ended successfully - it was possible to clearly hear individual fragments of the "sound background", including voices.
Leningrad Radio told about the described experiment, and almost immediately the assistant professor Nikolsky, who worked in one of the Moscow research institutes, responded. It turns out that Nikolsky and his colleagues dealt with the problem of computer recognition of written texts.
In their experiments, the next step was taken: from the page of their son's handwritten dictation, Nikolsky and his colleagues reproduced the sound of the voice of the teacher who dictated it! Similarly, they examined the surviving letter from the front of the war years, written with a chemical pencil. Here we even managed to hear the echoes of a distant battle …
This sensational message appeared on the pages of one of the Moscow newspapers (with a link to our experiments), and that was all of a sudden it all ended: more information about the further development of such works appeared in our press. And almost a quarter of a century has passed since that time!
Apparently, the notorious secrecy worked: “someone” realized that extremely interesting “sound” information could be extracted from any letter. On the other hand, it seems incredible that these works themselves, which are of extreme historical interest, would be suspended. For example, in principle, one could hear the voices of Leonardo da Vinci or Peter the Great. Or maybe some pharaoh - an Egyptian ruler three thousand years ago? At least it is now known that this is not a fantasy …
Valentin Psasomshchikov, candidate of physical and mathematical sciences. St. Petersburg