The film tells about the "Variophone" electro-optical synthesizer, created by Evgeny Aleksandrovich Sholpo, which allows synthesizing artificial sound tracks using the automated "drawn (graphic) sound" technique. E. Sholpo works at Variofon. The principle of operation of the apparatus. Off-screen, the 5th variation from Beethoven's piano sonata, recorded on the Variophone, is played.