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Digital Audio on VHS – The Technics SV-P100 [video]
- JohnTHaller 6y agoWatched this yesterday having no idea that this existed. It predates DAT and CD and looks like a device from the future for when it was released.
- deleted 6y ago[deleted]
- gregmac 6y agoSeeing this brings back a vague recollection of touring a radio station -- I'm going to guess in the early 90s -- and seeing a bank of VHS machines they used to record everything they broadcast. I think I (or someone) asked about them, as it was weird to see video cassettes in a radio station, and so I'm fairly sure it was actually VHS and not DAT or something proprietary. It definitely didn't look like machine in this video. I don't remember what the radio station was anymore, but it's very possible it was a college station. Was this a common thing, or am I just misremembering this? Maybe just a hack a college station would have done to use commodity hardware/tapes and get 6 hours of recording time per tape?
- DaiPlusPlus 6y agoVHS could store gigabytes on a typical tape, so it’s a good media for storing a day’s worth of audio output from a radio station.
- jccalhoun 6y agoThere was definitely a phase where individuals would record music to vhs - as Techmoan mentions towards the end, some vcrs could record quite good quality audio -- but I don't know if it was done by radio stations or just individuals.
- extra88 6y agoAround 1990, a classmate made a “mixtape” on VHS to play at a party for hours of continuous music that no one had to stop or mess with.
- MrRadar 6y agoThey were probably VHS HiFi decks used to record the day's broadcast so that they could prove to advertisers when/how often their ads played in case they were asked. You could fit up to 8 hours on a VHS tape in the slowest speed mode with extended-length tapes.
- roywashere 6y agoAt my local radio station at the end of the 90s they used the longest length VHS tapes to record the shows on long play to 'prove' to the musicians rights organisation which songs were played how often. The choice of medium had not much to do with the audio quality but mostly with the length of the tapes.
- ljf 6y agoI was going to post the same - I worked at a community station briefly in the 90s and they used a standard home VHS recorder that had audio (and video) component in on the front. A 4 hour tape and long play mode you could cover 24 hours with just 3 tapes. It was all a bit diy and remembering to change the tape if it fell in my show was pretty stressful, at least for a 17 year old. I also understood that it was a term of our (short) license that we had proof of what was said in air, should anyone make a complaint etc. since all our shows were played live.
- zbuf 6y agoYeah this was hugely common in the UK, as you could fit 8 hours of Nicam digital stereo on a VHS tape at long play, for your license obligations. And as a bonus the security cameras as well if you need it. All using readily available consumer gear with built-in timer. It would wear out every year or so. Some stations used the same VHS trick as a play out system to cover overnights as well. I recall one of the problems is the fire hazard of keeping 8 weeks or so of tapes.
- dsr_ 6y agoReminds me of https://en.wikipedia.org/wiki/ArVid https://en.wikipedia.org/wiki/ArVid (Data storage on VHS)
- bluedino 6y agoVideo showing how it worked from LGR: https://m.youtube.com/watch?v=TUS0Zv2APjU https://m.youtube.com/watch?v=TUS0Zv2APjU
- Wistar 6y agoIn 1983 or so, the studio I worked at had an Alpha Micro system with a VHS for data backup. I remember you could set the CRC, the cyclic redundancy check level, but don't remember much else other then it was pretty darn creaky although the Alpha Micro itself was great.
- drmpeg 6y agoWho remembers D-VHS? Digital video on VHS. https://en.wikipedia.org/wiki/D-VHS https://en.wikipedia.org/wiki/D-VHS
- jccalhoun 6y agoOf course Techmoan has done a video on it: https://youtu.be/jiu0LPeLQPE https://youtu.be/jiu0LPeLQPE
- drmpeg 6y agoCool. Thanks for the link. I developed the code for the IEEE1394 interface on the JVC 2nd generation decks (HM-DH40000U, HM-DH5U and HM-DT100U) when I was at LSI Logic.
- ThePowerOfFuet 6y agoUsername checks out.
- aardvark179 6y agoDigital audio storage on video predates this, and even VHS, by quite a long way. The whole reason we have the weird sample rate of CD audio is because it was one that could conveniently be stored and retrieved as a video signal in either PAL or NTSC.
- RainforestCx 6y agoSo interesting! I’d always wondered about the history behind this. After your hint, there’s more info here: https://www.cardinalpeak.com/why-do-cds-use-a-sampling-rate-of-44-1-khz/ https://www.cardinalpeak.com/why-do-cds-use-a-sampling-rate-...
- slashink 6y agoNot the only reason. A combination of CD targeting a useable spectrum just above 20KHz (human hearing) which meant having more than double due to Shannon-Nyqvist ( https://en.m.wikipedia.org/wiki/Nyquist–Shannon_sampling_theorem https://en.m.wikipedia.org/wiki/Nyquist–Shannon_sampling_the... ). With the need of filter cutoff on the high end, 44000 was enough to avoid aliasing and still have a good useable spectrum. The second part is finding a good sample rate that you can easily clock on VHS. That’s where the this stems from although they technically could have gone for a different sample rate at a lower bit depth. 44100 ended up being a good trade off between different requirements.
- aardvark179 6y agoYeah. I was going to type more about the Shannon-Nyquist limit, but was on my phone, and I've heard several people over the years assert that the 44100 sample rate was a very early form of DRM since "anybody sensible" would have picked 48000, and indeed did for various other formats where this restriction didn't apply.
- slashink 6y agoYeah also you are technically right. The specific reason we ended up at 44100 is a VHS constraint but the 44* ballpark was what I wanted to clarify. Nevertheless always fun to see this pop up on HN, there is so much forgotten reasoning about standards that we’ve carried over into the modern world.
- tibbon 6y agoADAT was pretty similar to this right, but later?
- wazoox 6y agoADAT was 8 tracks of digital audio on a S-VHS. It was actually quite different from this because it was definitely targeted to home-studios, and it didn't use any video encoding, it was digital from end to end (and 15 years later).
- ethagnawl 6y agoI only started watching this channel about six months ago, but have really been enjoying it. (I started supporting Techmoan on Patreon shortly thereafter.) If you're interested in hi-fi, photography, new/classic/weird/historical technology, I'd recommend checking out the rest of Techmoan's catalog.
- jasonjayr 6y ago"Technology Connections"[1] is another great channel with similar research + documentary on old technology, with amusing jokes thrown in. [1] https://www.youtube.com/channel/UCy0tKL1T7wFoYcxCe0xjN6Q https://www.youtube.com/channel/UCy0tKL1T7wFoYcxCe0xjN6Q
- ethagnawl 6y agoCan confirm. I don't remember which one I discovered first, but the YouTube you-may-also-like algorithm led me to the other.
- ilamont 6y agoI was involved in the indie music scene in the late 1980s and 1990s and recall similar systems to this - digital audio recorded on analog videocassettes. IIRC, WBRS, the radio station at Brandeis University, used one such system to record live performances at the studio in two channels of digital audio starting in the late 1980s. I also worked with a studio in Taiwan in 1997 that used analog video cassettes to record 16 channels of digital audio, which were then mixed down to 2 channels and burned to a CD-ROM. One of the limitations that we were very aware of at the time was being able to extract the audio from the tapes at a later date. No home users had gear that could play back the tapes, and it seemed that very few studios even had access to these specialized pieces of machinery. In the early 1990s, I also worked in a 24-track London recording studio, which still used very thick analog tape for multitracking, but would output demos or test mixes to the then-emerging DAT standard (https://www.newworldencyclopedia.org/entry/Digital_Audio_Tape https://www.newworldencyclopedia.org/entry/Digital_Audio_Tap...).
- Scoundreller 6y agoAhhh, DAT, the technology so good that the recording industry got congress to make it useless: http://www.brouhaha.com/~eric/bad_laws/dat_tax.html http://www.brouhaha.com/~eric/bad_laws/dat_tax.html
- Zenst 6y agoAh yes, then the whole blank recordable media TAX on blank tapes, I remember that, then the whole storm over writable CD's. https://en.wikipedia.org/wiki/Private_copying_levy https://en.wikipedia.org/wiki/Private_copying_levy
- LeoPanthera 6y agoAnd in fact TechMoan has done a DAT video, too. https://youtu.be/F4K1QKKPX_g https://youtu.be/F4K1QKKPX_g
- jeffbee 6y agoVHS is a great analog tape format, too. S-VHS HiFi audio recording rivals reel-to-reel multitrack tape quality (i.e. close to objective CD quality). Only problem is the tape life is terrible.