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

[Mi40793]

The quoted May 13, 1978 NYT article on DATE says 62 stations had bought receive equipment. It was an expensive box .

DATE was 4 audio channels, 15 kHz, 16bit, mux’d onto ~5.5 Mhz QPSK carrier, intended to ride above the video.

To my knowledge DATE was never used on the ATT terrestrial microwave system used for PBS video. ATT would not allow DATE on the terrestrial microwave links, serving a limited number of PBS stations, as it ‘violated ATT tariffs’.

This dispute led to PBS obtaining money from CPB to build their own complete network satellite distribution system, in service Sept 1978. It included over 300 downlink dish/antenna receivers (FM video and one channel FM subcarrier for mono 15khz audio) and a ground uplink station Springfield, Va., and leasing Western LC Union satellite transponders. This allowed PBS stations to receive stereo programs (not all programs were stereo) via DATE if they purchased a decoder, or FM mono if not. NPR used the other two DATE channels. The cost of the complete PBS satellite system was equivalent to 10 years of ATT microwave line charges at 1978 rates.

The ‘big three’ networks used 5kHz telephone circuits for audio until ~1978 when ATT added FM subcarriers providing 15kHz audio. ATT used Farinon FM modulators above the video at about 5-5.5 MHz.

Quad tape audio at 15 ips would do 15 kHz.
16mm television film projectors, ~6 or 7 kHz (best I ever saw)
TV station audio transmitter, audio path, etc., 15 kHz, same as any FM radio station required.

Working at two networks, everything audio was kept as flat a response as possible, with agc and peak limiting at transmitters.

[Eric H]

The Music and often dialog for filmed shows would have been recorded separately from the film, the Music would have been done in a studio to the same standard as any other music recording, it would have been put together later in post production.

This is why they can remaster movies and TV shows years later with upgraded audio mixes.

[Mi40793]

The quoted May 13, 1978 NYT article on PBS developed DATE (Digital Audio for Television) says 62 stations had bought receive equipment. It was an expensive box.

DATE was 4 audio channels, 15 kHz, 16bit, mux’d onto ~5.5 Mhz QPSK carrier, intended to ride above the video.

To my knowledge DATE was never used on the ATT terrestrial microwave system used for PBS video. ATT would not allow DATE on the terrestrial microwave links, serving a limited number of PBS stations, as it ‘violated ATT tariffs’.

This dispute led to PBS obtaining money from CPB to build their own complete network satellite distribution system, in service Sept 1978. It included over 300 downlink dish/antenna receivers (FM video and one channel FM subcarrier for mono 15khz audio) and a ground uplink station Springfield, Va., and leasing Western Union satellite transponders. This allowed PBS stations to receive stereo programs (not all programs were stereo) via DATE, if they purchased a decoder, or FM mono if not. NPR used the other two DATE channels. The cost of the complete PBS satellite system was equivalent to 10 years of ATT microwave line charges at 1978 rates.

The ‘big three’ networks used 5kHz telephone circuits for audio until ~1978 when ATT added FM subcarriers providing 15kHz audio. ATT used Farinon FM modulators above the video at about 5-5.5 MHz.

Quad tape audio at 15 ips would do 15 kHz.
16mm television film projectors, ~6 or 7 kHz (best I ever saw)
TV station audio transmitter, audio path, etc., 15 kHz, same as any FM radio station required.

Working at two networks, everything audio was kept as flat a response as possible, with conventional agc and peak limiting at TV transmitters.

[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

[ChrisW6ATV]

OK. All of this is quite interesting.

[kfbkfb]

https://www.bbceng.info/Technical%20...digits-fm.html
^^^
On the 14th of September 1972 the link from Broadcasting House to the Wrotham transmitter switched to the new BBC PCM (Pulse Code Modulation) system.


I had read about the BBC using PCM for national FM audio distribution (funnily, when the CD appeared in ~1982, some complained that 16 bits wasn't enough, they were reminded that they had been listening to 13 bit PCM since ~1972)


Kirk Bayne

[KentTeffeteller]

Other big reason for HiFi soundtracks. Music and concert shows. Which also before MTS were simulcast by FM Stereo stations.

[kfbkfb]

https://bayarearadio.org/sf-radio-history/netsnd
^^^
A few stations in extremely small markets used 3.5 kHz circuits.


(just found this, provides some background about national audio distribution)


Kirk Bayne

[Kevin Kuehn]

From the title I thought the discussion was going to be more along the lines of "Why bother with Hi Fidelity Soundtracks?". A lot of us old guys would be lucky if we can hear much above 8khz. Fortunately for us there's not much intelligence up there that keeps us from surviving.
Good music still sounds just fine.

[kfbkfb]

I guess my question could be summed up as:

The limitations of the (USA) radio and TV national audio distribution systems were well known, did anyone tell the composers about the limitations?


Kirk Bayne

[Kevin Kuehn]

Do you seriously think there was a conspiracy? For a reality check consider all the folks today listing to music and video soundtracks on their teeny weeny cell phone speakers. Do you think they know what they are missing, or even care to plug in an ear bud?

[Electronic M]

Originally Posted by kfbkfb

I guess my question could be summed up as:

The limitations of the (USA) radio and TV national audio distribution systems were well known, did anyone tell the composers about the limitations?


Kirk Bayne

Given the fidelity limitations were on the transmitter end, NO TV could make it sound better than it was....Thus if the composers owned TVs or spent enough time around someone else's TV logically they should be able to hear for themselves how limited the medium was....All except for Bethoven.

[W.B.]

Originally Posted by Mi40793

The ‘big three’ networks used 5kHz telephone circuits for audio until ~1978 when ATT added FM subcarriers providing 15kHz audio. ATT used Farinon FM modulators above the video at about 5-5.5 MHz.

Quad tape audio at 15 ips would do 15 kHz.
16mm television film projectors, ~6 or 7 kHz (best I ever saw)
TV station audio transmitter, audio path, etc., 15 kHz, same as any FM radio station required.

Working at two networks, everything audio was kept as flat a response as possible, with agc and peak limiting at transmitters.

Between Jan. 26 and Feb. 26, 1978, from what I have read, was the period when the transition from the old 100 Hz-5 kHz telco audio to the diplexing system that allowed 50 Hz-15 kHz audio transmission was effected. Apparently the later date was when the old telco audio was shut off permanently.

[TVBeeGee]

I have something to add to this thread. Primetime episodics from that era were usually shot and also post produced on 35mm film. 35mm optical sound has MUCH higher frequency response than the 16mm optical sound you may have heard at your local TV station, or in a classroom. 35mm running speed is nearly three times faster than 16mm, roughly 90 feet per minute, versus only 33 feet per minute for 16mm. Faster media makes reproduction of high frequencies easier. But, that's not all.

Sound post was done using 35mm mag film media, which is audio-only film with a magnetic audio coating mostly across its full width and no photosensitive emulsion. It has sprocket holes along each edge just like 35mm photographic film and also runs at 90 feet per minute. That's 18 inches per second, folks.

Mag film fidelity was incredible for the era, due to wide tracks, higher mass, fast speed, and a very stiff base compared to audio tape. Track skew and wow and flutter were all amazingly low due to mass and dimensional stability.

Mag film was typically used throughout the post process, including the final mix. The visual editing produced a silent "picture master." The audio post produced an "audio-only mag track master." Both final elements were then used to create any 35mm release prints with optical sound that might be needed for network play.

The 35mm optical soundtracks provided to the networks were very good, theatrical in quality, much better than network distribution could support in that era, but sound from the magnetic film is even better.

In most cases, the production studios kept the separate picture and sound masters and those are often used as the sources for what you see and hear today.