The Trautonium is an electronic synthesizer invented in 1930 by Friedrich Trautwein in Berlin at the Musikhochschule's music and radio lab, the Rundfunkversuchstelle. Soon afterwards Oskar Sala joined him, continuing development until Sala's death in 2002. Description 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 until 1935 (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 position at which the performer pressed the resistive wire into contact with the plate beneath it which effectively changed its length, with suitable technique 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 Concerto for Trautonium with String Quartet. He also soloed in the debut of Hindemith's student Harald Genzmer's Concerto for Trautonium and Orchestra. Paul Hindemith wrote several short trios for three Trautoniums with three different tunings: bass, middle, and high voice. His student Harald Genzmer wrote two concertos with orchestra, one for the monophonic Trautonium and, later, one for Oskar Sala's "Mixtur-Trautonium". One of the first additions of Sala was to add a switch for changing the static tuning. Later he added a noise generator and an envelope generator (so called 'Schlagwerk'), formant filter (several bandpass filters) and the subharmonic oscillators. These oscillators generate a main pitch and several subharmonics, which are not multiples of the fundamental tone, but fractions of it. For either of the (now two) manuals, four of these waves can be mixed and the player can switch through these predefined settings. Thus, it was called the "Mixtur-Trautonium". Oskar Sala composed music for industrial films, but the most famous was the bird noises for Alfred