Like video, television sound has dramatically changed since network TV’s early days when 7.5kHz monaural landline telco television network audio bandwidth was the prime-time norm. State-of-the-art early quad machine audio such as the Ampex VR-1000 was 50Hz to 10Khz at 50dB s/n with 3-percent RMS distortion. Later, the most advanced high-band Quad machines achieved 50Hz to 15KHz monaural audio at 55dB s/n. Satellites brought 15KHz national network audio to stations in the 1970s.
A rare few music programs were simulcast in stereo on local FM stations until multichannel television sound (MTS), the U.S. standard for stereo broadcast, was authorized by the FCC in 1984. By 1985, approximately 70 TV stations in the U.S. were broadcasting MTS. Not all TV stations broadcast in stereo, so a disclaimer graphic reading “In Stereo where available” appeared at the beginning of most network programs for several following years. By the 1990s, analog television audio had reached its plateau until DTV opened new opportunities for more dramatic sound improvements.
Today’s TV viewers are listening more closely than ever before. Viewers/listeners fall into one of three categories. One is the audiophile, who may be listening on an expensive Dolby 5.1 or 7.1 THX or similarly approved high-powered home theater audio system. The second is the viewer listening with a less expensive home theater system with external amps and speakers, in stereo, 5.1 or 7.1. The third is the average viewer listening with the standard speakers and amplifier built into their TV display. Most modern off-the-shelf big screen TVs incorporate excellent built-in sound systems.