to listen through headphones two decades after the appearance of the american radio engineer notaniel baldwin, literally in the kitchen, assembling his own version of headphones with good sound quality. this invention the americans stand. in this year with the discovery of the so-called dynamic loudspeaker, the part in which the electrical signal is converted. in sound quality , the sound quality becomes cleaner and better thanks to what was created for this purpose in germany in 1937, but these headphones still had a drawback. they transmitted sound, only in mono format, that is, it came through one channel, except for it was necessary to listen to the recording from two microphones through mono headphones , this did not work, therefore, i had to invent my own cossos model became revolutionary and it is still being produced the first popular model in 1968. it is worth noting that, despite all the convenience of the invention, listening to music, while it was possible only through a tape recorder, or by connecting headphones to music, where you want somewhere in 1995, manufacturers began to u