Stereophony

The word stereo has become a noun meaning a stereophonic audio system, but more correctly it is an adjective describing a sound reproduction system where, by recording on two or more microphones, it was possible to recreate the image of space, just as does the human ear. The brain detects phase differences in the sound waves received at the two ears, and by complex analysis delivers to the mind directional information, so that you know where a sound is coming from. This was the concept of the early sound engineers experimenting in stereophony, who discovered that not only was the directional information helpful, but the complex combination of sound received from two speakers by two human ears recreated in the brain the atmosphere and ambience of the recording.

I was keen on the concept of stereo from a scientific perspective and I constructed a stereo receiver from a Heathkit before stereo was broadcast by the BBC, and built a remotely-operated rotating dipole antenna in the attic to receive signal from Caen in France. My second taperecorder in about 1960 was a 4-track stereo Tandberg, and I always obtained stereo source material to tape whenever possible.

Stereo is best listened to in a room where the listener is ideally situated in relation to the speakers, or on headphones, though Q-Sound, and the new Bose radio use phasing tricks to enlarge the stereo image. True stereo is easy to create on any home taperecorder with two mics, or a single stereo mic (two sensors pointing at an angle). Play the result back and get a remarkable feeling of presence. I have always enjoyed recording choirs and church musical events for this reason. I made recordings of my son James as a child singing in choirs that sound superb.

Today it's hard to hear good stereo. With every instrument separately miked, and the signals then mixed to death, there is no true stereophonic phase-shift information to record, since stereophony requires at least two (and preferably no more than two) microphones to receive each sound source. So we get pseudo stereo, where two or more playback channels are used to create an artificial impression of space merely by the relative amplitudes of the signals relayed to them.

But some of us hanker after true stereo, seek it out, and discuss it, as on the link below. In the 1950's classical recordings were available with a close approximation to true stereo - just two mics. Classical recording today still remains much closer to a stereo ethic than pop recordings. Many live recordings exhibit true stereo characteristics, including in the popular field. Recordings made in churches are sometimes made with just two mics suspended from on high, and the results can be excellent.

The recording engineer has conflicting requirements and must compromise: he wants a close-up-to-the-mic sound, but he knows this will contain little stereo phase data.

I have in mind using the symbol SS instead of S on my collection if I consider a recording to be true stereo (but have not yet implemented this).

Red Bird recordings issued in true stereo
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