Musique Concrète


During World War II, whilst radio reporters in the battlefields of Europe were preparing their recordings on shellac-coated disks, the Nazi propaganda machine was broadcasting material prepared on the recording machine of the future. This was the Magnetophon, the first real tape recorder.

At the end of hostilities, the arrival in Britain of these advanced machines came as a shock, persuading EMI to build the British Tape Recorder 1 or BTR/1, mainly based on the original German design. As in some continental machines, the tape heads on this recorder faced away from the operator, making tape editing very tricky. This was corrected in the company’s next model, the massive BTR/2, many of which remained in service at the British Broadcasting Corporation (BBC) until the 1970’s.

Miniature valves made it possible for EMI’s later machine, the TR/90, to fit into a standard 19-inch rack or into a mobile trolley. All these professional machines incorporated three tape heads (erase, record and replay), allowing the user to check the quality ‘off tape’ whilst creating a recording. But in Britain, the most significant machines were those destined for the semi-professional or amateur market, notably the Ferrograph, beginning with the Series One, remaining almost unchanged until the Series Five, followed by the more modern Series Six and Series Seven machines.

Indeed, it was the enthusiastic amateur and experimenter who often saw the real potential for the tape recorder. Although the use of tape and a dextrous razor blade had been originally used for generating propaganda, it also could be employed creatively to change the nature of recorded sound.

In 1948, Pierre Schaeffer used tape manipulation of natural and mechanical sounds to make a pioneering radio programme. His new techniques, known in artistic circles as musique concrète, used tape recorders to create new sounds from old. He used ‘spooling noise’, played tapes backwards or at different speeds, or turned the spools by hand. By using a machine with a variable-speed capstan motor, the pitch of a sound could be modified with musical accuracy. Later on, the BBC Radiophonic Workshop used a Leevers-Rich recorder with a rotary switch calibrated in musical intervals.

Tape Sampling

All the principles of what we now call sampling were now established. Any source material could be used and then processed in any manner, and the only limitation was the producer’s imagination. Most sources of sound were familiar to drama studios, including breaking glass; gravel in boxes; percussive noises produced by musical instruments, bottles or metal tanks; machinery and street sound.

Samples, unlike synthesised material, contain the complex harmonics, and harmonic decay, of natural sounds. The effect can be disconcerting or dramatic, as in the sounds of dinosaurs used for the film Jurassic Park, created from those of real animals. But as the pitch is moved further away from that of the original, it develops characteristics different from real sounds: the pitch change alters the subjective ‘size’ of a sound but ignores the physical properties of the materials that created it. And of course, the harmonic content of real sounds varies across the musical scale. For example, every note on an acoustic piano is different, each string vibrating the others differently, changing as the note decays.

Then, as now, you needed a clean recording of every sample. In addition, the beginning and end of each sample would have to be carefully trimmed using a razor-blade. Extra samples could be produced by dubbing (copying) the original recording onto another machine. To change a sample’s pitch, the original recording would be dubbed from a varispeed machine onto another recorder, using a separate ‘pass’ for each required pitch change. Finally, all the samples, modified or otherwise, would be edited together into a continuous sequence using a razor-blade, editing block and splicing tape.

To create a long cross fade, a special editing block, incorporating an exceptionally shallow splicing angle could be used. For normal editing, a cut at 90 or 45 degrees was common, although the latter could often give an unacceptable ‘jump’ in the image of a stereo recording: fortunately, most early examples of musique concrète were produced in monaural (mono) sound. Any sample could be made into a continuous sound by carefully splicing together the ends of a recording to form a tape loop.

Time Delays

Having discovered the useful delay introduced between the record and replay heads of a tape machine, the concrète pioneers explored the possibilities of running a tape directly from the left hand spool of one tape machine to the right hand spool of another, passing both sets of record and replay heads.

By drawing the tape out between two machines on a sprung loop stand (or bottles, if stands weren’t available), the delay on the output from the second machine could be extended. Also, the audio output of the second machine could be carefully mixed back into the input of the first machine, so creating rising and falling ‘waves’ of sound. The guitarist Robert Fripp, an ex-member of King Crimson, was so enamoured with this trick he christened it Frippertronics, many years after it was first used.

Phasing and Flanging

Two other effects that briefly saw popularity were phasing and flanging, both caused by upsetting the azimuth (the vertical angle of the tape head) during recording or playback, usually by touching the flange of a tape spool. Neither could be described as musical, but they were very dramatic.

Phasing was the result of combining the input and output of a tape machine, or the two outputs of a stereo machine. As the phase between the signals changed, the output at certain frequencies, and their harmonics, was cancelled out, an effect identical to a comb filter. Flanging was similar, but relied on feeding some the tape machine’s output into the input, almost causing oscillation at some frequencies. The result was more metallic than phasing and was used on many pop records of the sixties.

Stretching the Tape

The success of tape manipulation spawned some novel devices. One example, the Binson Echorec Baby, had a spinning metal drum, surrounded by tape heads that produced multiple delays. Another device, the Tempophon, was strapped to the side of a tape machine, with the tape passing its spinning replay head. Since the tape speed in relation to this head was set by the Tempophon itself, irrespective of the actual speed, it was possible to vary the pitch without altering the tempo.

The BBC’s Programme Effects Generator (PEG) provided ‘spot effects’ for radio drama, including The Archers. This device used a separate tape cartridge for each effect, the tape being pulled out of the cartridge, played and then drawn back in again. A further development of PEG was the Mellotron, a keyboard instrument with cartridges containing sampled instruments. The Moody Blues used this successfully in their sixties ‘symphonic’ rock music, despite its sluggish mechanism. Roland also used tape cartridges, this time as a loop, providing very long delays in one of their effects devices.

At the BBC Radiophonic Workshop, established in 1958 to explore the possibilities of music concrète, sound montages were created using several tape machines and an audio multiplexer. This specially-constructed device contained of a circle of fixed capacitor vanes, connected to the outputs of the tape recorders. The multiplexer’s output came from a rotating vane, driven by a variable-speed motor. As this turned, each signal was heard in sequence, one sound fading into the next.

Early Sound Processing

Reverberation was popular, disguising small blemishes and providing a consistent atmosphere to a completed recording. Echo rooms, plates and springs were commonly used. Most echo springs gave awful results, although hitting them could often generate interesting sounds! One popular trick involved copying a tape backwards and adding reverb, then playing it forwards to give a reverse echo.

Equalisers, preferably of the ‘graphic’ type, were much in vogue for musique concrète. Passive versions, comprising simply of coils and capacitors, often provided a remarkable degree of quality (Q), enabling dramatic changes to be made to any sound. And at the Radiophonic Workshop, the mechanical ‘Dalek’ voices for Doctor Who were created using a simple ring modulator, consisting of three transformers and a ring of four diodes. An untreated speech signal was connected to the ‘main’ input, with a low frequency (usually upwards of 15 Hz) applied to the ‘carrier’ input.

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©Ray White 2001.