Radio history - VCR based automation system

[jesseg]

I don't know why "CD quality analog audio" should be funny, per se. It happens to be true.

Even simply having enough bandwidth doesn't make something "CD quality" by consumer norms. I think the term is non-technical AND subjective. Not objective.

For example: any random layer3 encoder @ 128kbps stereo is "CD quality" according to ~all PMP marketing.

I took what you said literally (you're a freakin engineer man), as if you were burning CD-Rs and recording back to VCR or some other backward process. That would actually be "CD quality analog" objectively, and funny, I thought.

The punchline; the one thing we don't usually see the words "CD quality" used on is an actual CD player.

their goal was to meet or exceed CD specs

It looks like they got pretty close in some ways. To me; CD's lack of traditional non-linear distortion is what stomps tape as a storage media. Not that a spec would tell you how it reacts to audio at all.

I still have a 20 year old Panasonic professional grade VCR with balanced audio. In Hi-Fi mode, it has a 20Hz to 21kHz audio passband (+ or - 0.1dB) and has an audio dynamic range of 94dB. I think that's close enough to count as CD quality.

It's closer than most things that use the term. No question. But I still have to laugh when it's used in a professional engineering context.

 

[Kmagrill]

I took what you said literally (you're a freakin engineer man), as if you were burning CD-Rs and recording back to VCR or some other backward process. That would actually be "CD quality analog" objectively, and funny, I thought.

As a matter of fact, many stations did do that. Our group owned a very large library of TM Gold disks which were highly prized. Since personal CD burners were still about 10 years away, those CDs were all archived to AFM for safe keeping. About 10 years later, one of those backups was used to recreate some damaged or lost CDs. I'd bet it would be hard to measure any difference between AFM and a CD, much less hear such a thing. Those backup CDs sounded pretty identical to the originals. Perhaps someone out there can hear the difference between the original and the backup, but I've never found anyone that can.

Standards are moving targets. If you were around before CD burners and digital recorders, your definition of pro quality would be different than it is today. In the 1980s, "professional audio" was half-track, 1/4" reel to reel tape at 15ips. Those of us working in broadcasting of the day worked with decks where the SNR was typically less than 60db and I seldom got one to pass 20kHz audio. The typical Otari decks found in many stations had SNRs in the mid 50s. I don't recall what the THD and IMD specs were. The point was that AFM gave us audio recording capabilities that was better than the professional standards of the day, in decks that cost less than $1000. Only the CD player, which was not a recordable medium in the 80s, was as good.

 

[satech]

I have a lot of respect for the JVC engineers that designed the HiFi VCR audio system.
{snip}
The helical scanned FM audio has over 1 mHz of bandwidth to work with, so it's easy to get very high resolution out of the audio.

Some have claimed to measure the frequency response of a VHS Hi-Fi recording to be at least 150 kHz. With that in mind, I should try recording the MPX output of my FM processor to VHS Hi-Fi, then playing it back into a transmitter and see if I get a stereo signal on the air!

Of course, there was also a non-"HiFi" VHS Stereo system using the linear audio tracks on the tape. I have an old VHS Stereo VCR and it is able to pass 15 kHz audio with surprisingly good quality (at least at SP speed!) but even with Dolby B NR the S/N is only as good as a cheap Type I cassette. IIRC, the audio response drops down to about 12 kHz at LP speed, and all the way down to about 7 or 8 kHz at SLP/EP speed.

 

[chriscollins]

I have a lot of respect for the JVC engineers that designed the HiFi VCR audio system.
{snip}
The helical scanned FM audio has over 1 mHz of bandwidth to work with, so it's easy to get very high resolution out of the audio.

Some have claimed to measure the frequency response of a VHS Hi-Fi recording to be at least 150 kHz. With that in mind, I should try recording the MPX output of my FM processor to VHS Hi-Fi, then playing it back into a transmitter and see if I get a stereo signal on the air!

Of course, there was also a non-"HiFi" VHS Stereo system using the linear audio tracks on the tape. I have an old VHS Stereo VCR and it is able to pass 15 kHz audio with surprisingly good quality (at least at SP speed!) but even with Dolby B NR the S/N is only as good as a cheap Type I cassette. IIRC, the audio response drops down to about 12 kHz at LP speed, and all the way down to about 7 or 8 kHz at SLP/EP speed.

When I was young, I recorded audio only on VHS. It sounded quite good and gave me a 4 hour (LP) music mix.

 

[mikl73]

I was at a station in the early 90's that used VCR to automate overnights by recording the afternoon in a slightly generic format so the time and wx sounded correct when it replayed over night. At 1pm the Tape started recording everyday. At 1AM it was played back.

 

[level42]

In my recording studio life, there was a period of time where we mastered records to HiFi VHS. We used a semi-pro RCA model that had level controls and a terrific audio section. Always worked pretty well, though I still preferred 1/4" half track reel-to-reel. There was another system that Sony built that was basically an A/D converter, and the digital output of the converter went into the video in on a Sony Beta or Umatic video deck...then there was a decoder that was fed from the video output. Those were actually fairly common for a while in pro studios...you can read up on it here: http://en.wikipedia.org/wiki/PCM_adaptor

 

[Kent T]

VHS VCR decks were made for, ahem. Consumer use. Light duty. HiFi VHS is not a mastering medium. 1/2 track or full track open reel at 15 IPS or 30 IPS is, better digital formats are. VHS is not a broadcast medium either except for high end SVHS on Cable or Public Access stations at best. And the VHS tracking stability is a joke. The companders mandated for the VHS Hi-Fi format sometimes can audibly pump and breathe.

 

[WPHA]

The companders mandated for the VHS Hi-Fi format sometimes can audibly pump and breathe.

Feed them properly-compressed audio, and they shouldn't do that anymore.

 

[Kmagrill]

VHS VCR decks were made for, ahem. Consumer use. Light duty. HiFi VHS is not a mastering medium. 1/2 track or full track open reel at 15 IPS or 30 IPS is, better digital formats are. VHS is not a broadcast medium either except for high end SVHS on Cable or Public Access stations at best. And the VHS tracking stability is a joke. The companders mandated for the VHS Hi-Fi format sometimes can audibly pump and breathe.

We used a similar companding system (DBX) to compress our cart libraries in the '80s. It worked well.