The Trautonium is a monophonic electronic musical instrument invented about 1929 by Friedrich Trautwein in Berlin at the Musikhochschule's music and radio lab, the Rundfunkversuchstelle. Soon Oskar Sala joined him, continuing development until Sala's deat
Instead of a keyboard, its manual is made of a resistor wire over a metal plate, which is pressed to create a sound. Expressive playing was possible with this wire by gliding on it, creating vibrato with small movements. Volume was controlled by the pressure of the finger on the wire and board. The first Trautoniums were marketed by Telefunken from 1933-35 (200 were made).
The sounds were at first produced by neon-tube relaxation oscillators (later, thyratrons, then transistors), which produced sawtooth-like waveforms. The pitch was determined by the amount of resistive wire chosen by the performer (allowing vibrato, quarter-tones, and portamento). The oscillator output was fed into two parallel resonant filter circuits. A footpedal controlled the volume ratio of the output of the two filters, which was sent to an amplifier.
On 20 June 1930 Oskar Sala and Paul Hindemith gave a public performance at the Berliner Musikhochschule Hall called "Neue Musik Berlin 1930" to introduce the Trautonium. Later, Oskar Sala toured Germany with the Trautonium; in 1931 he was the soloist in a performance of Hindemith's Concert for Trautonium with String Quartet. He also soloed in the debut of Hindemith's student Harald Genzmer's "Concert for Trautonium AND Orchestra".