The Electronic Music Studio in Westdeutscher Rundfunk (WDR) in Cologne was founded in 1951 by composers Werner Meyer-Eppler, Robert Beyer and Herbert Eimert (the studio's first director) and was based on the ideas of Meyer-Eppler presented in his book "Elektronische Klangerzeugung: Elektronische Musik und Synthetische Sprache" from 1949. This dissertation defined the theoretical nature of a studio based on electronically synthesized sound - in sharp contrast to Pierre Schaeffer's concrete music at GRM in Paris.
The studio was initially equipped with a Monochord, a modified version of the monophonic Trautonium built specifically for the studio by Friedrich Trautwein. It also had the Melochord, an instrument originally built by Harald Bode (1909–1987) in 1947 for Meyer-Eppler to be used in his lectures and demonstrations in physics. The melochord had two monophonic tone generating systems that were separately controlled by a split five-octave keyboard, where the top three octaves could be assigned to one tone generator and the bottom two octaves to the other. Two notes could be played simultaneously. It also had controls for shaping the envelope ("attack-sustain-decay") of the sound. In 1953, WDR studio commissioned Bode to build another Melochord for them. The new model had two separate keyboards. Another novelty was the ability to control the filter from the keyboard, "tuning" the timbre of the sound. For example, while holding the tone constant you could change its color.
In addition to these instruments, the studio consisted of the following devices:
• Signal generators (oscillators): sinusoidal, square, sawtooth and noise,
• Filters: octave, 1/3-octave,
• Pulse generator,
• White noise generator,
• Ring modulator,
• Rotary speaker for recording surround sounds,
• Echo and reverberation chamber: the reverberation chamber was a large, empty room where sounds can be played through the speakers and re-recorded with added room acoustics.
• 16-channel audio mixer,
• Patchbay for connecting modules,
• Tape recorders: several mono, 2-track and one 4-track tape recorders (This was one of the earliest produced 4-track tape recorders. Studio WDR used four-channel tape recorders long before the rest of the world. Most studios around 1957 was still adapting to two-channel tape recorders.) and a variable speed tape recorder "Springer" with a rotating playback head.
The first musical achievements of the studio in Cologne were the works of Eimert and Beyer. They dealt with the physics of sound and theories about the musical structure bordering the mathematics. The studio itself was little like a place to create music, more like a research lab. There was nothing accidental about the first electronic music compositions produced in the WDR studio. Eimert demanded discipline and control from everyone he invited into his circle of experimenters. Seeing electronic music as a means of exercising control over every structural aspect of a piece, they constructed their earliest pieces by means of additive and subtractive synthesis, using sine waves as the primary ingredient.
While it would have been a blasphemy in 1954 to call the music from the Cologne studio "musique concrète", there were in fact great similarities in the approach to the structure and editing used by both studios at the time. The piece Klang im unbegrenzten Raum (1952) by Eimert and Beyer sounds very "acoustic" in its spatial movement of sound, reverberant depth and blurred tones. Eimert's Klangstudie I (1952) has little in common with the serialistic approach, with repetitive waves of sound spectra and dramatically roaring noises that appear and disappear in the streams of reverberated sounds.
The engineers were the "silent" geniuses behind most classical electronic music studios. Fritz Enkel (1908–1959) held this position at WDR, and Jacques Poullin at GRM in Paris.
Under the leadership of Herbert Eimert, the WDR Electronic Music Studio quickly became a meeting place and forum for an international group of avant-garde composers, such as Ernst Krenek (Austria/USA), György Ligeti (Hungary), Franco Evangelisti (Italy), Cornelius Cardew (England), Mauricio Kagel (Argentina), Nam June Paik (Korea), and Gottfried Michael Koenig, who became WDR's technical assistant helping many composers in their work, and who created at WDR many key electronic music pieces of those years. The language and technology of early electronic music culminated in his equally radical and virtuoso works: Klangfiguren II (1955/56), Essay (1957) and Terminus I (1962).
The pioneering work of these composers was completed by the arrival of Karlheinz Stockhausen at the WDR in 1953 (who replaced Eimert as director in 1962) and the creation of such works as Gesang der Junglinge (1956), Kontakte (1960) and Hymnen (1967), which became groundbreaking works in the achievements of electronic music.
In retrospect, the influence of the Cologne School was significant on several levels. First, the WDR studio is considered the "mother of all studios". It became a model for comparable institutions, such as the Phonological Studio of Bruno Maderna and Luciano Berio in Milan (established in 1955) or the Polish Radio Experimental Studio of Józef Patkowski in Warsaw (1957), which also worked with sine waves, noise and pulse generators, tape recorders, filters and reverb devices. Second, Stockhausen, who for a long time was considered the most important figure integrating this creative discipline, helped electronic music to gain international respect.
Third, many composers starting their work on electroacoustic music in Cologne passed on and developed the ideas they encountered there. Gottfried Michael Koenig, who headed the Netherlands Institute of Sonology since 1964, reorganized it as a kind of "Cologne studio criticism", introducing most of all voltage control and computers.
The equipment of WDR's composers did not change much in the 1950s. By 1960, composers continued to use the same basic sine wave and noise generators and primitive filters that were in place when the studio was founded. It was equipment intended for taking scientific measurements, not for composing music. The studio's equipment was upgraded to Stockhausen's requirements in the early 1970s to incorporate, then standard, the voltage-controlled modular synthesizers, including the custom-made EMS Synthi 100. The WDR studio remained in use until 2000, when it closed. Some of the original equipment has been saved from destruction and is now stored in the basement of the WDR building in Cologne, Germany.