VHS multitrack

[A Reel Person]

I was gonna say that!!!

..................

 

[The Ghost of FM]

..................

[Yosemite Sam] Great leapin' Horny toads!! [/Yosemite Sam]

 

[robin watson]

Hmmm........... any chance you've heard of ADAT???? (these little gizmos caused a minor revolution in the Recording Industry back in the 90's........)

What a condescending fucking tosser.

 

[The Ghost of FM]

What a condescending fucking tosser.

Are we competing with the Microphone forum?

Let's not.

Cheers!

 

[K.C. Maloney]

i'm glad somebody takes the time to answer perfectly reasonable questions instead of just taking cheap jabs.. the guy was obviously asking about analog recording to that format (since this is the analog only forum), and i have wondered that myself.. thanks ghost, now we know.

if you don't have something nice to say...

Yeah, really. I HATE people who think that since they have more experience with a particular subject that they are superior to everyone else, including people who are just starting to get into something like pro audio.

Every elitist audio jerk out there was once a novice too. And when they were a novice, I bet they didn't like people insulting them because they didn't know as much as people who had more experience.

You can't learn things without asking questions. That's what this board is here for. If you know everything already, WHY THE HELL ARE YOU HERE? Did you read this post just because you thought it would give you a chance to be an asshole?

Sorry, I know this is off subject, but I hate it when I see people getting picked on for no reason. The guy was asking a reasonable question and he deserves a reasonable answer, not some smartass remark.

 

[themaddog]

Cheap jabs

Yeah, I don't mind the cheap jabs. I just think it's kind of funny when they originate from people who own "real" studios where people pay money to go and record. I could only imagine what it's like to record in such a "professional" studio like they own, and what great people they must be to work with.

Thanks for your help everyone, this thread is pretty much dead, he he.

-MD

 

[TransducerX]

Standard VCR's at SP, run at 1,7/8ips; the same speed as a standard home cassette deck and if you've ever heard the quality,(or lack there-of) of the linear soundtrack on a VCR you'll know pretty quickly why the analog multitrack VCR never caught on.

Keep in mind too that video tape is a completely different formulation that is optimized to recording video only in a helical scanning system that speeds up the writing speed to capture video frequencies which are in the megahertz.

Audio recorders need tape that is optimized and designed for the frequency's range in kilohertz and as cheap and plentiful as blank video cassettes are its like being in the desert and being surrounded by miles of free sand when all you really needed is a glass of water.

Cheers!

Not dead!

I had this same idea the other day. After searching around, this thread was about the only thing of relevance that I found.

"if you've ever heard the quality,(or lack there-of) of the linear soundtrack on a VCR you'll know pretty quickly why the analog multitrack VCR never caught on."

I have only heard the sound from the 2 audio tracks and that was always pretty good; good enough to master to in some (cheap) cases. Which was what sparked the idea. That and the fact that there is now miles of this tape available for virtually free.

TBH, I don't even know what the "linear soundtrack on a VCR" means. Could you share? What's the problem? As mentioned, the two audio tracks that you get off a standard formated VHS tape is pretty good.

"video tape is a completely different formulation that is optimized to recording video only in a helical scanning system that speeds up the writing speed to capture video frequencies which are in the megahertz.

Audio recorders need tape that is optimized and designed for the frequency's range in kilohertz"

This makes sense. But if this was the case, that the tape itself isn't built for audio, then how are we getting good quality from the 2 audio tracks that are there?

 

[Farview]

If you are talking about the hi-fi audio tracks, those are not the analog linear tracks. That audio is encoded with the video signal and will suffer from the same tracking problems that will make the top of the piture scew, etc... It is captured at the same 29 some odd frames per second that the video is.

The linear audio tracks are the ones you hear on a non hi-fi vcr and when the tracking is off on a hi-fi vcr. You know, the lifeless muddy sounding ones.

 

[TransducerX]

If you are talking about the hi-fi audio tracks, those are not the analog linear tracks. That audio is encoded with the video signal and will suffer from the same tracking problems that will make the top of the piture scew, etc... It is captured at the same 29 some odd frames per second that the video is.

The linear audio tracks are the ones you hear on a non hi-fi vcr and when the tracking is off on a hi-fi vcr. You know, the lifeless muddy sounding ones.

Hmm. Per the wiki entry, it looks like the audio is laid down just like on any other analog tape:

Around 1985, HiFi VCRs emerged, adding higher-quality stereo audio tracks (20 Hz to 20 kHz with more than 70 dB S/N ratio) which are read and written by heads located on the same spinning drum that carries the video heads with frequency modulation. These audio tracks take advantage of depth multiplexing: since they use lower frequencies than the video, their magnetization signals penetrate deeper into the tape. When the video signal is written by the following video head, it erases and overwrites the audio signal at the surface of the tape, but leaves the deeper portion of the signal undisturbed. (PAL versions of Betamax use this same technique.)

 

[themaddog]

It's funny, because I first posted this almost four years ago, and it went on to become one of the more hostile threads for the analog section.

I was new to this forum, had plenty of questions, and glad I stuck it out - because I've certainly learned a lot!

-MD

 

[sweetbeats]

it went on to become one of the more hostile threads for the analog section

Now that's something to be proud of!

Transducerx,

But if this was the case, that the tape itself isn't built for audio, then how are we getting good quality from the 2 audio tracks that are there?

The bottom line is, if the audio quality meets your needs, then it works for you.

I remember thinking of doing this year ago when "Hi-Fi" VCR's starting getting really cheap, and I was even more of a cheapskate than I am now (and they're just silly cheap now), but I know it wouldn't meet my needs now. That is based on my own criteria of audio quality needs and not yours.

I'm totally not wanting to be snobbish or anything, but "good quality audio" is totally subjective here.

One self-evident kicker in this for me is that if a brand-new hi-fi VCR, which can be had for little over $30 was really designed as, and did an effective job at being a two-track audio mastering deck, the things would be going like hotcakes. Its a totally different animal than an analog mastering deck, period.

For somebody on a serious budget to master demo archives or something, it definitely would be a viable option IMO. I'm picturing a cassette multitracker with a hi-fi VCR next to it...I'd still rather master to a good cassette deck and then to PC though, or just direct to PC. Computers are so readily available as are decent quality soundcards...many of them onboard and there is free recording software readily available as well...

 

[Farview]

Hmm. Per the wiki entry, it looks like the audio is laid down just like on any other analog tape:

Around 1985, HiFi VCRs emerged, adding higher-quality stereo audio tracks (20 Hz to 20 kHz with more than 70 dB S/N ratio) which are read and written by heads located on the same spinning drum that carries the video heads with frequency modulation. These audio tracks take advantage of depth multiplexing: since they use lower frequencies than the video, their magnetization signals penetrate deeper into the tape. When the video signal is written by the following video head, it erases and overwrites the audio signal at the surface of the tape, but leaves the deeper portion of the signal undisturbed. (PAL versions of Betamax use this same technique.)

Read it again. The audio is written by the spinning head in helical stripes. That means that the tracking has to be dead on in order for it to be even read. Normal analog tape records the signal in a straight line along the length of the tape, not in little stripes 30 time a second.

 

[TransducerX]

OK, let me throw this out there:

What kind of LOE for the development of a multi-track tape head would some of you estimate?

"Read it again. The audio is written by the spinning head in helical stripes."

I could have read it a thousand times and it wouldn't matter. I'm just not as smart as you.

So answer the question above.

 

[Farview]

So answer the question above.

What is LOE?

 

[JR#97]

OK, let me throw this out there:

What kind of LOE for the development of a multi-track tape head would some of you estimate?

"Read it again. The audio is written by the spinning head in helical stripes."

I could have read it a thousand times and it wouldn't matter. I'm just not as smart as you.

So answer the question above.

This is something I looked into back when I was an audio/video mastering engineer. We were thinking if you substituted the 2 video heads for FMA heads and increased the tape speed, you could get 4 tracks. But tracking would be crucial. Things track better at higher speeds.

But there really isn't any advantage of the hi-fi over a good analog tape machine. We made bin loop masters for cassette duplication on 4 track 1/2" tape and that had better specs than the hi-fi.

The one advantage to hi-fi VHS is convenience. 2 hrs in a cassette vs dealing with open reel.

In the early days we had a sony pcm f1 converter and stored digital audio on vhs tapes.

 

[TransducerX]

What is LOE?

LOE means Level of Effort, typically measured in man hours. It's corporate R&D speak.

 

[TransducerX]

This is something I looked into back when I was an audio/video mastering engineer. We were thinking if you substituted the 2 video heads for FMA heads and increased the tape speed, you could get 4 tracks. But tracking would be crucial. Things track better at higher speeds.

But there really isn't any advantage of the hi-fi over a good analog tape machine. We made bin loop masters for cassette duplication on 4 track 1/2" tape and that had better specs than the hi-fi.

The one advantage to hi-fi VHS is convenience. 2 hrs in a cassette vs dealing with open reel.

In the early days we had a sony pcm f1 converter and stored digital audio on vhs tapes.

So as mentioned before, you simply feel the tape quality/type does not merit audio recording? Or did you not get far enough along with the FMA heads to hear a test case?

 

[sweetbeats]

Easy fellas...

Hey TransducerX

Farview is right.

You know how the record head looks on an analog recorder right? And the tape just runs over that stationary head, right?

Well, and if you know this alrady please don't take offense...just trying to fill you in if you weren't aware , but the head on a VCR spins, like a barrel on its side, and the tape passes over the side of the barrel. The barrel isn't exactly perpendicular to the tape travel path either, it is angled so that the info that gets printed to tape is in diagonal stripes accross the tape rather than parallel to the tape. So it isn't linear analog audio, it is non-linear digital audio. Its the same way with any digital tape recorder whether it be an ADAT, DAT, or DTRS like the Tascam DA38, 78, 88, etc. So a hi fi VCR is a digital two-track audio tape recorder, but that's not what its speciality is. Hence the analog to digital converters (and digital to analog as well) are going to be low-quality and low performance in terms of their specifications. Trying to get the audio portion to be of better quality and or trying to add tracks to would be doing what Alesis did with the ADAT, which, though VERY popular, did have its ups and downs.

Really was an innovative bit of kit and what they did right (as opposed to what happened to the poor AKAI MG1212/1214, which was originally supposed to use a Beta tape shell but there were haggles over licensing or something) was use a readily available format (the VHS tape), but of course the converters, head design and such were proprietary. We can also thank Alesis though for the very popular ADAT optical lightpipe. Really has stood the test of time and made its debut on their ADAT decks.

So, IMHO, trying to do something more with the hi-fi VHS format, though a fun topic, is probably not realistic. Developing a proprietary head design for that format, a road which has already been traveled (and is far less traveled today thanks to the affordability of computer-based recording, which has a far less mechanical transport ), would be an exercise in futility. I think a venture like that would be silly expensive too, though again I would say for general purpose two-track recording the hi-fi VHS can fit the bill if it sounds good to the individual.

 

[Beck]

...and it went on to become one of the more hostile threads for the analog section.

What! And I didn't even post in it before now.

 

[mshilarious]

Somewhere back a year ago or so I measured my garden-variety Sony VCR against a Tascam cassette rack unit (not multitrack). The VCR handily beat the cassette in frequency response and noise, but still not much to brag about; I think the cassette managed 16kHz and the VCR 18kHz. SNR was as described above (and typically less for cassette). I also noted a fair amount of intermodulation distortion of high-frequency signals on the VCR, possibly due to the recording format as described by farview.

In short, it might be more convenient than 1/2" reel tape, but I highly doubt it specs anywhere near as well. And that doesn't address the multitrack issue.