Phone (wired) does not require power supplies do it yourself! (tested at 20 meters)

This article is not about perpetual motion or zero energy :)
However, there are still some interesting moments - “How can this work at all?”

Let's return to our Soviet childhood, some remember how they spoke through match phones (2 empty boxes, 2 matches, regular sewing threads):
tying matches to the ends of the rope and piercing with matches the box tension between two users.
When you speak in one box, the sound waves make the rope vibrate, in which you can hear with your ear attached.

I thought, isn't it possible only in the electronic version?
Just connected 2 phone speakers among themselves provadami observing isolation.
The search scheme is brilliantly simple:

In one speak in another you listen no additional tricks are required.
Of course, the distance for which the scheme will work is limited.
Personally, I checked at 20 meters (I simply didn’t have the opportunity to reach the wires at that time)
I suppose 100-200 meters of audibility will not suffer (of course, depends on the wire.
And with a shielded cable, it is possible to cover the distance even more.
Due to the lack of amplifiers and other nodes - the voice of the interlocutor that you will hear by putting your ear to the speaker - will not differ as if he was standing nearby and talking to you.

I tested with different speakers. later TK-67-NT was convenient for the working standard version of the radio (country house in the village - connection to the bathhouse which is 20 meters away)

Ideally, it was possible to make 2 pairs of wires (maybe you can just locally connect it in parallel - xs need to be tested or theoretically experts on the laws of ohm can say - what's so bad?)
or even two handsets. so that it is not necessary to listen and speak in one nest.