Experiments with adding stereo sound to television broadcasts began in 1958, when ABC broadcast several episodes of The Lawrence Welk Show with two-channel audio. This was accomplished by sending one channel over the TV signal as normal, and the other channel over the ABC AM radio network. Viewers at home could really only have taken advantage of this if their TV set had its single speaker off to one side, and they were able to place their radio right next to the TV on the other side, and carefully set the volume of each to match. Even then, the low-fidelity signals couldn’t do justice to the musical performances on the show (which was the whole point of the experiment) and the idea was quickly abandoned.

Once the technology to allow a stereo signal to be sent over FM radio frequencies became available in 1962, the BBC plus several stations in the US began simulcasting certain music-oriented shows. The TV station would provide a stereo reel-to-reel tape of the audio signal for the program to its FM radio broadcast partner, and a system was worked out so that the audio tape was started playing at precisely the right moment so that it was in sync with the video signal. Viewers at home could tune their TV to the channel (but leave the volume turned all the way down) and hear the music in FM stereo quality over their stereo receiver and speakers (assuming they were in the same room as the TV set.)

Public television station WTTW in Chicago made frequent use of this technique for the show they produced, Soundstage, which featured musical performances recorded at the WTTW studio. In 1975, a company called Telesonics approached WTTW with a plan to broadcast a high-fidelity stereo audio signal on the same frequency as the TV video signal, thus ending the need for an FM simulcast. All testing of the new technology was conducted by WTTW for FCC approval and eventual adoption by all stations nationwide. WTTW began broadcasting in stereo full-time in October 1983. The FCC rules for Multichannel Television Sound were adopted on April 23, 1984.

While WTTW had already been sharing their prototype technology with other PBS stations for years, the first major network to adopt stereo broadcasting was NBC, which began offering stereo sound for The Tonight Show with Johnny Carson on July 26, 1984 (although only WNBC in New York had installed a stereo transmitter by that date.) By the fall of 1994, all four major networks had their entire prime time lineups in stereo.

TV manufacturers quickly began adding stereo speakers to their higher-end sets, and/or RCA output plugs to the back so that users could pass along the stereo audio signal to their receivers.