Hi-Fi TV Soundtracks (pre 1978) - Why?

[old_tv_nut]

Can you explain a bit more what the upgrade was and what instruments you think were affected?

[ChrisW6ATV]

Originally Posted by kfbkfb

IIRC, in 1978, TV sound distribution (USA) was upgraded.

Originally Posted by old_tv_nut

Can you explain a bit more what the upgrade was and what instruments you think were affected?

If I remember discussions of TV sound distribution at that time (I was a teenager just getting my first VCR soon afterward), most or all network TV audio was distributed on two voice-grade AT&T lines, being processed at both ends so that the second line carried the converted higher frequency content. When recombined/converted at the receiving end, the result was sound up to 8 kHz roughly.

I first noticed the potential for improvement when I had the line-level audio from my Sony SL-7200 VCR connected to my stereo system in late 1979. The sound from local station WGN (Channel 9 in Chicago) was quite good, and far better than any of the network stations had.

Is a change away from the voice-grade lines what you are referring to as the "post-1978 upgrade"?

[Mi40793]

Network audio nationally was always just single ‘5khz’ equalized circuits to the local stations, for both the radio and tv networks.

Telcos provided special ‘local loops’ for example, studio to transmitter 15 khz equalized lines, but you paid dearly for these, and you’d better check that response yourself.

In 1978 two FM subcarriers were added above the network video channels at about 5-5.5 MHz. These were typically Farinon units and were flat to 15kHz. ATT’s network video channel was wide enough to carry the two added FM subcarriers above the video bandwidth.

Local tv stations always had the capability, and were required to be capable of transmitting 15kHz audio, same as any FM station, but not all program sources were 15khz audio. Particularly network audio until the above system was installed.

[kfbkfb]

Originally Posted by ChrisW6ATV

Is a change away from the voice-grade lines what you are referring to as the "post-1978 upgrade"?

Yes, I had read about the PBS DATE audio system upgrade, I first noticed improved audio (in the late 1970s) on the CBS evening news, transmitted by WMT ch 2 and viewed (via roof antenna) on a Sylvania GT-Matic TV.


Kirk Bayne