The trautonium is a monophonic electronic musical instrument invented[1] about 1929 by Friedrich Trautwein in Berlin at the Musikhochschule's music and radio lab, the Rundfunkversuchstelle.[2] Soon Oskar Sala joined him, continuing development until Sala's death in 2002. 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[3][4] (later, thyratrons, then transistors), which produced sawtooth-like waveforms.[5] 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.[6]
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 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 harmonics, which are not multiples of the fundamental tone, but fractions of it. For any 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 Hitchcock's The Birds. The Trautonium was also used in the Dresden première of Richard Strauss's Japanese Festival Music in 1942 for emulating the gongs- and bells-parts and in the 1950s in Bayreuth for the Monsalvat bells in Wagner's Parsifal.
The German manufacturer Doepfer sells some devices for the commercial market to allow for Trautonium-like synthesizer control.[7]