There
have been four separate stages in the development of music recordings studios,
roughly aiigned with each decade since the 1950s. Until the late 1940s, music
was recorded in two ways, both mono. Many recording sessions were done direct
to disc, with one or more lacquer masters cut right in the studio. If the music
was for a film soundtrack, it was recorded directly onto a 35mm optical soundtrack
negative. Running at 18 inches per second, and with about 55 dB signal to noise
ratio (abbreviated S/N, a parameter we'll define later), this method gave better
overall sound quality than any disc of the time.
Tape recording, developed by the Germans during the Second World War, was used
both in radio broadcasts and for the deciphering of intercepted code messages.
The poor sound quality obtained on that early equipment, due largely to inferior
tape, soon improved with the introduction of commercial recorders and new tapes
by Telefunken in Europe and Ampex in the United States. These machines were
mono, full track (one 1/4" wide track), running at 15 ips for music-quality
performance. Lower speeds were usually reserved for voice recording. It was
discovered early that you could overdub by playing back a previously recorded
tape through a mixer, blending that with live mics, and sending the composite
signal to a second recorder. In the history of record production, this simple
step rivaled the invention of the wheel.
Obviously, the pretaped music lost a bit of sound quality and gained a bit of
noise. Nevertheless, this technique did allow artists to add layers of new music.
Such mono-to-mono copy-overdubbing was the standard in pop music production
up until 1962. Until that time, pop and rock records were made to sound good
on AM radio-in highly compressed mono. Not much attention was paid to true stereo
in pop and rock until 1967, when the Beatles brought out Sgt. Pepper's Lonely
Hearts Club Band. While stereo was entering its second decade for classical
and jazz recording, these genres were played primarily on FM. Rock was usually
confined to AM until the early 1970s.
