Previously: Music in the Night
By the early 1950’s televisions were finding their way into many American homes. Hollywood had to find ways draw people back to theaters that people just could not get at home. Films such as The Robe, Shane, and Julius Caesar, as well as many others used new processes, both visual and aural. Among those lures was stereo soundtracks.
At the same time, improvements were being made to existing technologies found in homes. Advancements in radio and phonograph records were being developed, expanding on experiments that had been conducted in the 1930’s.
Records: Early stereo disk experiments used two systems: the single groove system used by Blumlein and Bell Labs, and a two pickup system used by others. In the early 1950’s, a sound engineer named Emory Cook (1913–2002) marketed records that used a two pickup system. For each piece there were two monophonic bands on the record, each to be tracked by its own pickup. One example is of Willis Page conducting New Orchestral Society of Boston performing Beethoven’s Fifth Symphony from 1954. The timing between the two channels seems to be a bit off. The two channels are fairly close so the distance between the styli is probably correct, but perhaps one stylus is just a little bit ahead of the other in terms of what it is playing. I heard that problem on every sample of the system I found on YouTube. Obviously, proper alignment of the two styli is critical to this system.
Cook had previously experimented with recordings out in the field that were known for their fidelity such as this record from 1952 which he recorded along the New York Central Railway. He was lucky: if I tried such a recording I would have had people coming up and asking, “So what are you doing?”, ruining the recording.
Cook wanted accurate sounding recordings — “HiFi” before the term came into use. He knew of single groove stereo recordings but the technology of the early to mid 1950’s limited the audio quality that could be obtained with single cutting and pickup devices.
Cooks two-pickup system did not have much of an impact, nor did stereo tapes which were first released commercially in 1955. Experiments in England by two companies, London and Decca were being conducted in the mid 1950’s but they used much of the same technology that had been used experimentally before. In the US, RCA and Westrex worked on a different system that used the two sides of the groove for the two channels rather than modulating the bottom of the groove as had Blumlein. This gave the Westrex system compatibility with monaural records. While the older system could play monaural records it would only play the audio on one side as the bottom of the groove, where the other channels audio would be, contained no information. The Westrex system would play audio on both sides — it was just the same signal with a monaural record. Several companies were fighting it out on the minor details with the final winner being a system developed by Columbia records. This system used lateral modulation of the groove — each side of the groove had the audio for one channel.
Limited edition stereo discs were released in late 1957 with major developments in equipment and disk availability in 1958.
More detailed information is available here.
Radio: In the early 1950’s many owners of AM stations were starting FM stations, more as a hedge against the future than for any short term goal. With the growing interest in stereo, and having not much else to do with their FM stations, the concept of using two radio stations to broadcast stereo programming was revisited. That was before the FCC implemented the NRSC curve in 1990 and there was not as much electrical noise on AM as there is today so it was not a bad match to have the left channel on an AM station and the right channel on the FM station. Many people would use two different radios to accomplish this, but there were some receivers built to accomplish this in one unit.
May I introduce the Bell 2445. My father bought one of these units in 1964. I had it through 1983. By that time it was having many problems so I got rid of it.
Before you play the video, let’s look at the front panel.
Notice that it has a separate tuner for AM and FM. If you look at the selector knob (second from the left) you will see that it has a position for AM-FM. That is why the two separate receiver sections. It allowed you to play AM for the left channel and FM for the right.
Just to the left of top center you will see a position marked AUX-MX (we called it Aux-Mix). We assumed that AUX meant “auxiliary” but we had no idea of what MX stood for, but now I know it means “multiplex.” In other words, FM stereo. The reason for such an unusual arrangement was because this unit was designed before an FM standard was adopted in the U.S. Our unit did have FM stereo — not that we knew what it was. The FM stereo circuit was an add on that was inserted in the left (as viewed from the front) rear portion of the chassis with two little cables that came out and plugged into the auxiliary jacks.
There were fourteen differing systems considered by the FCC. Of those, systems by Zenith and GE were close enough that they were virtually identical. The FCC decided on that system in April 1961, effective July 1, 1961 (at midnight local time of stations). The first station to use the new system was WGFM in Schenectady, New York.
For more information look here.
The system adopted by the FCC was important in one respect: it was compatible with mono radios.
In later years an AM system was adopted. By that point music had all but abandoned the AM dial. With increased noise from modern technology and the implementation of the NRSC curve in 1990 that limited the highest frequency to 9.5 kilohertz, there was not much reason for AM stations to get the stereo equipment or consumers to buy the radios.
An AM/FM combo station I worked at in the mid 1980’s went stereo on the AM. On January 1, 1985, I was simulcasting. I knew the chief engineer had an AM stereo receiver in his office. I got it out and used that as the monitor. However, as was the case with most consumer gear, the frequency response was much lower than what the station’s AM air monitor provided, although the monitor in the studio was monaural.
Today it seems that, despite advancements in technology, interest in high quality audio is waning. That is too bad.