[Davesrose]

So there's a YouTube channel I watch for various explanations of technology (ranging from Haunted Mansion at Disney, toasters, or old video formats). I thought it interesting that with the latest video, there's a general overview of how PCM audio was implemented before computer data storage systems had the capabilities for storing the data. That the first system was developed in the 60s that ran off video tape to PCM adapter (and by the 70s, PCM adapters were using U-matic videotape). This video highlights how Sony also acounted for this with Betamax and had home PCM adapters. I see in the comments, some are saying that they had music teachers who had these consumer PCM adapters recording digital audio on video tape. Apart from high fidelity recording, they also offered long recording time (like up to 8 hours). I think it's also interesting that one primary reason 44.1kHz became standard was due to videotape.

https://en.wikipedia.org/wiki/44,100_Hz#Recording_on_video_equipment

 

[sander99]

Another use case:
There have been hobbyists making 4 channel (quadraphonic) recordings using a HiFi Video Recorder plus PCM adapter.
("HiFi Video Recorder" was the name for a video recorder with a specific way of recording audio: FM modulated using rotating heads, which gave a dynamic range of over 80 dB.)
They recorded 2 channels through the PCM adapter to the video input, and the other 2 channels to the "HiFi" audio inputs.
The two different "audio paths" had different latency, leading to a delay of 2 of the channels compared to the other 2 channels. (I assume the PCM would be delayed.) But that didn't seem to matter, even gave a nice spacious effect, depending on how they placed the mics etc.

 

[bigshot]

One of my first jobs in the business was working in a sound house run by a location sound mixer. He would record during the day, and then I would come in at night and transfer the select tapes to mag stripe film. He was the first location mixer to use PCM. It was a two part Betamax unit with a PCM half and a tape half. We only had one, so he would leave it with me at night to do the transfers. I played with it quite a bit. It was a little bigger than a Nagra and it didn't run on clockwork or batteries like a Nagra. But it worked very well. We did the first show in Hollywood to be recorded digitally. It was a Barry Manilow TV special.

 

[gregorio]

I think it's also interesting that one primary reason 44.1kHz became standard was due to videotape.

I don’t believe that’s true. Although the first digital recorder was based on videotape and that became a line of development for some companies in the 1970’s, none of those systems operated at 44.1kHz. Denon’s original recorder operated at 37.5kHz and Decca’s at 48kHz for example. The most important/influential development was by SoundStream in 1976, because it demonstrated commercial usability, but it was not based on videotape, it was based on a 16 track “instrumentation tape recorder” by Honeywell, originally running at sampling rate of 37kHz but the commercial models a year later ran at a 50kHz sample rate. 3M’s entry to the market also ran at 50kHz (and again was not based on videotape). Sony developed a videotape based professional audio recorder (U-Matic), which ran at 44.056kHz and is the only videotape format which achieved mainstream professional use but not for recording, it was used exclusively for transferring masters. Sony also demonstrated a prototype recorder based on reel-to-reel stationary head linear-scan (DASH) technology in 1977, although they didn’t bring it to market until 1982 but along with ProDigi’s reel-reel stationary head recorder they almost completely dominated the professional studio (digital) recording industry for over a decade. Apart from U-Matics for transferring masters, there was no videotape technology involved.

G

 

[71 dB]

I think it's also interesting that one primary reason 44.1kHz became standard was due to videotape.

It has more to do with video standards (PAL and NTSC).

PAL has 588 active line per frame out of 625 and 25 frames per second. Storing 3 sample points per channel on each active line we have 588 x 25 x 3 samples = 44100 samples per second.

B&W NTSC has 490 active lines per frame out of 525 and 30 frames per second. Storing 3 sample points per channel on each active line we have 490 x 30 x 3 samples = 44100 samples per second.

Colour NTSC has 490 active lines per frame out of 525 and 29.97 frames per second. Storing 3 sample points per channel on each active line we have 490 x 29.97 x 3 samples = 44056 samples per second.

 

[Davesrose]

It has more to do with video standards (PAL and NTSC).

Videotape was the storage medium for video, and kept those same standards. The Wikipedia link I included went over these standards (and how PAL & B&W NTSC are 44.1kHz, and color NTSC 44.056kHz). The whole article on 44.1kHz covers the use of videotape with PCM adapters (like Sony’s PCM-1630). As the video shows, Sony had the intent to support PCM storage early in the development of Betamax (that a 1970s home recorder had a PCM switch). The particular consumer PCM unit he shows from the early 1980s also has a switch for the early 14bit ADC/DACs as well. Since Sony was one of the contributors to compact disc, it becomes evident why 44.1kHz was chosen. Through more reading, I see that Sony's first demonstration with a prototype PCM adapter using tape was from Heitaro Nakajima (who left NHK in 1971 to join Sony). The X-12DTC prototype introduced in 1974 was the size of a refrigerator and used 2" tapes. By 1975, when Sony was developing Betamax, they tasked Nakajima to produce a smaller unit recording off videotape.

 

[bigshot]

I think the one I used was the PCM F-1. There was a matching beta recorder that went with it.

 

[Davesrose]

I think the one I used was the PCM F-1. There was a matching beta recorder that went with it.

So looking it up, the PCM F-1 came out in 1982 as a portable PCM device that was also sold with the SL-2000 Betamax portable recorder (and with that, there was a separate TV tuner unit). Sony's first consumer PCM processor was the PCM-1 in 1977 (recording to Betamax). The PCM-1600 was introduced in 1978 and recorded to U-matic tape. Interesting that 1982 was also the year that Sony started introducing their professional video system, Betacam. Here is what the SL-2000 looks like with its battery pack:

Tech info on the unit:
https://mrbetamax.com/DescriptionSL-2000.htm

 

[gregorio]

The whole article on 44.1kHz covers the use of videotape with PCM adapters (like Sony’s PCM-1630).

That’s not true, the article covers various things, not only Sony’s PCM adapter.

Since Sony was one of the contributors to compact disc, it becomes evident why 44.1kHz was chosen.

It’s evident to you (and only you!) because you’ve only investigated one part of the history, which unsurprisingly appears to be according to your personal agenda of video.

What you’ve failed to investigate or understand is all the other contributions to the development of the CD standard and therefore that videotape played virtually no role, except as effectively a discarded stepping stone along the way. As I mentioned previously, there were numerous lines of development in digital audio recording in the mid-late 1970’s, only some of which were based on videotape technology. Indeed Sony itself followed more than one of those lines and had different teams working on different solutions but you’ve effectively only investigated one (and not the right one!).

What actually happened is Sony introduced the Betamax VCR in 1975 and then in 1976 developed the videotape PCM adapter (PCM-1) to use the Betamax VCR as the digital recorder. At the same time, another team in Sony were working on video laser disk (manufactured by Philips) and as this technology was seen as the future, yet another team of engineers were set the task of trying to pair the PCM-1 with the laser disk to create a digital audio laser disk. However, the results were poor and in Sony’s OWN words (Making Digital Audio a Reality - Sony.com):

“After looking into the causes, Doi [project leader] made three decisions. The first was to use the PCM-1, which they had been preparing to launch in the autumn of that year, as an adapter exclusively for Betamax. This was a simple and logical decision. The second decision was to approach the audio disc and the videodisc as unrelated items and give priority to developing audio technology. In other words, to develop a brand new way to directly record the digital audio signal onto an optical disc, instead of using a video signal from a video recording format.” - The 3rd decision was to develop better error correction.

So while one team were working on the development and release of the PCM-1/Betamax and eventually the PCM-1600/U-matic, another team were developing a completely different system and it’s this system that Sony took to the table with Philips in 1979 to develop the CD Redbook standard! Also at this time Sony were developing another tape based digital audio recorder, the PCM-33xx series. The 3302 was for 2 track mastering, the 3324 was a 24 track recorder and the 3348 a 48 track recorder (which wasn’t launched until 1989 due to technical issues). The 3324 was introduced in 1978 and is actually credited (disputed) with the first ever digitally recorded film score (Star Trek, The Motion Picture). Again, this 33xx series did NOT use videotape or videotape based technology, they were DASH reel-reel machines using 1/4” and 1/2” tape respectively.

G

 

[Davesrose]

You previously went on another diatribe about early digital systems that weren’t recording 44.1kHz (why you insist I’m wrong, then start arguing over oranges instead of apples?). It was the PCM-16xx and U-matic tapes that were used for mastering for CD: tape offered multiple recording sessions (that you didn’t get with laserdisc).

From that Wikipedia article: “The 44.1 kHz sampling rate originated in the late 1970s with PCM adaptors, which recorded digital audio on video cassettes,[note 1] notably the Sony PCM-1600 introduced in 1979 and carried forward in subsequent models in this series. This then became the basis for Compact Disc Digital Audio (CD-DA), defined in the Red Book standard in 1980.[1]”

https://www.sony.net/Products/proaudio/en/story/story02.html

 

[gregorio]

From that Wikipedia article: “The 44.1 kHz sampling rate originated in the late 1970s with PCM adaptors, which recorded digital audio on video cassettes,[note 1] notably the Sony PCM-1600 introduced in 1979 and carried forward in subsequent models in this series. This then became the basis for Compact Disc Digital Audio (CD-DA), defined in the Red Book standard in 1980.[1]”

The sampling rate originated because as SoundStream had ALREADY discovered that Telarc and the other record labels would only accept a new format which covered the full 20Hz-20kHz spectrum and along with the bare minimum space for anti-alias filters of 2kHz, therefore the absolute minimum sample rate would have to be at least 44kHz. Combine this with the fact that optical media/laser reader technology at the time was far more prone to error and the more optimal sample rate of 50kHz employed by other digital audio recorder developers was not possible/practical with CD. So what sample rate is above 44kHz but as low as possible? The two obvious choices are therefore the 44.056k or 44.1k sample rates supported by the PAL or NTSC specifications, as @71 dB explained.

https://www.sony.net/Products/proaudio/en/story/story02.html

And how does that contradict anything I’ve stated or what Sony states in the same article in chapter 7?!

G

 

[Davesrose]

The two obvious choices are therefore the 44.056k or 44.1k sample rates supported by the PAL or NTSC specifications, as @71 dB explained.

Why would they be obvious, when according to you, video has nothing to do with the decision for 44.1kHz?

And how does that contradict anything I’ve stated or what Sony states in the same article in chapter 7?!

G

I edited my previous post as you posted this. The link confirms that Sony’s PCM-16xx series (using U-matic tape), was a popular format for CD mastering.

 

[gregorio]

Why would they be obvious, when according to you, video has nothing to do with the decision for 44.1kHz?

I’ve already answered that question: “What sampling rates are above 44kHz but as low as possible?” The obvious choice would be one of the two most common TV broadcast formats.

I edited my previous post as you posted this. The link confirms that Sony’s PCM-16xx series (using U-matic tape), was a popular format for CD mastering.

I know that, I’ve used one! But again, how does that contradict anything I’ve stated previously? Again, the only example of videotape technology used in CD creation was the U-matic and that was only ever used for transferring masters, not for recording, editing, mixing or anything else. And even Sony themselves intended the PCM-3302 (which was not videotape based) to be used to transfer masters, BEFORE they even sat down to discuss the CD format with Philips!

G

 

[Davesrose]

I’ve already answered that question: “What sampling rates are above 44kHz but as low as possible?” The obvious choice would be one of the two most common TV broadcast formats.

Your whole arguments on this thread have been that early digital PCM formats were not 44.1kHz, and that I was wrong in suggesting that videotape was a prime reason for siding with 44.1kHz. Yet here you are now saying 44.1kHz was sided because of video formats

I know that, I’ve used one! But again, how does that contradict anything I’ve stated previously? Again, the only example of videotape technology used in CD creation was the U-matic and that was only ever used for transferring masters, not for recording, editing, mixing or anything else. And even Sony themselves intended the PCM-3302 (which was not videotape based) to be used to transfer masters, BEFORE they even sat down to discuss the CD format with Philips!

G

You just admitted that video was a reason for going with 44.1kHz. Far from your previous claim that videotape was just some discarded technology, it was the basis of Sony's first PCM adapters, and would still be used for mastering. Doesn't it stand to reason that since Sony had already decided on 44.1kHz as a DAC standard, that would also be for their multitrack recorders? In fact, the next page after "The birth of digital audio technology and its dramatic progress.", is about their multi-track recorders.

 

[gregorio]

Your whole arguments on this thread have been that early digital PCM formats were not 44.1kHz,

Which they weren’t. Even the early videotape based formats weren’t. Sony’s own early efforts were at 37.5kHz.

and that I was wrong in suggesting that videotape was a prime reason for siding with 44.1kHz.

And I supported that argument by quoting Sony themselves who stated they had: “to develop a brand new way to directly record the digital audio signal onto an optical disc, instead of using a video signal from a video recording format.”!

Yet here you are now saying 44.1kHz was sided because of video formats

No I’m not! I’m clearly saying a CD standard was required that was as low as possible but above 44kHz, so even if TV broadcast standards or videotape had never been invented, the standard would have been set around 44.1kHz anyway but due to the fact in the wiki article YOU posted “44,100 is the product of the squares of the first four prime numbers (

) and hence has many useful integer factors.” and also that it’s the max supported rate by the PAL TV broadcast standard, it’s an obvious/sensible choice.

G