From Mono to Stereo and Beyond, Part 1

16 Dec 2014

For the first 80 years of recorded sound, everything was monophonic or “monaural.”  This meant that the recording was made using just one device—an acoustic horn, a microphone—to collect the sound and deliver it to the recording device. 

All sound was reduced to a single channel with everything appearing to come from a single direction.

Phonograph cylinders and all discs (78s, 33 1/3 RPM LPs and 45 RPM singles) were all monaural recordings prior to 1958.  AM radio and TV audio was also in mono.  However, we have two ears which give us the ability to determine the direction and origins of sound.

Attempts to create binaural (literally “two ears”) recordings began as far back as 1881 when Clement Adler demonstrated a two-channel audio system in Paris.  Running wires from telephone transmitters connected set up on either side of the stage of the Paris Opera, listeners in a nearby room could listen to a primitive stereo transmission by using a different receiver for each ear.

Using similar technology, the Théâtrophone (“theatre phone”) distributed two-channel performances to subscribers over telephone lines.  The system was popular in Europe and the UK from the late 1800s to the late 20s.

In 1933, Alan Blumlein, an engineer at EMI, patented stereo records.  With his method, each wall of the groove of the record carried different information, separating the music into left and right channels.  Despite other experiments with stereophonic sound Blumlein’s method would become the standard for stereo discs twenty-five years later.  However, because EMI neglected to renew the patent, they failed to get the credit (or the revenue) they deserved.

The development of multi-channel sound was also a priority for the motion picture industry.  Bell Laboratories, Universal Pictures, 20th Century Fox and Disney all worked to bring more vivid audio to their productions.  Disney’s Fantasia (194) was the first commercial movie to be shown with stereophonic sound.  They called it “Fantasound.”

Stereo and multi-track recording became much more straightforward with the advent of magnetic recording tape in the late 1940s.  The first public demonstrations of stereo tapes came in 1952.  The following year, Remington Records became one of the first labels to tape all its sessions in stereo.  RCA Victor soon followed.  Early audiophiles were able to enjoy these performances using reel-to-reel tape machines.  Stereo recording equipment began to become the standard in studios by the late 50s.

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