From: glambert@pyramid.com (George Lambert)
Newsgroups: rec.music.gdead
Subject: Re: Best Tapes
Date: 29 Aug 92 22:11:36 GMT
Distribution: na
Organization: Pyramid Technology

In article <1992Aug28.220659.4602@vicorp.com> mc@vicorp.com (Mark Charalambous) writes:
	Original explanation of 'head switching' and life expectancy of video
	tapes deleted.
>
>George
>
>I don't have much experience with this but let me say this:
>1) I haven't noticed this problem so far. All the tapes I have were
>recorded on a different VCR than the one I own.

That's great.  I'm glad to hear it.  Nevertheless, the problem exists, and 
I'm sur you'll hear it sometime.  I've heard it from tapes made in other
friends decks, and sometimes I haven't.  It depends upon how closely the
heads align from one machine to the next.  I hear it about 30% of the time on
pre-recorded commercial tapes.
>
>2) If this is true and is prevalent as you seem to imply, wouldn't there
>be a lot of noise about this since we're talking about the video signal
>also? I mean, wouldn't people who've copied video tapes (w/video on them)
>have noticed this by now, and wouldn't it have become an accepted demon
>of the medium as say tape hiss is on cassettes?

It comes up on rec.video every once in a while, so there are others who've 
noticed it too.  The general reaction is "oh well, what might've been".  Not
that many people really even hook up there Hi-Fi decks to a stereo, let
alone use them for audio archiving, and most people who would choose VHS
over Beta or laser are hardly very discriminating of quality reproduction,
anyway.  I don't mean to sound like a snob here, but I own all three systems,
and VHS is sorely lacking compared to the other two.  VHS won the tape media
war by offering 6-hour vs 5 hour recordability time.  It was a classic example
of quantity winning out over quality.  C'est la guerre.
>
>But now that I'm writing this I'm remembering that a big difference between
>VHS and Beta is how the audio track is laid down. Beta's method is supposed
>to be superior because it uses more of the tape, or something like that.

They are both 1/2" video tape media.  Beta Hi-Fi (the original) mixes the 
audio and the video together in the same frequency bandwidth.  VHS Hi-Fi
actually layers the audio beneath the video layer on the tape, although they
both use the same amount of tape width (about 7/16", the other 1/16" is used to
lay down the linear audio tracks.)  Beta is far less prone to head-switching
noise than VHS because of the difference in laying the audio tracks, but it
does occasionally exhibit the same symptom.
>
>So is waht you're saying just specific to the audio tracks?

Yep.  Remember that both tape systems were developed primarily for video
signals, and audio was a low grade afterthought.  Sony found its systems
going into more quality conscious homes, but fewer overall.  To make up
for market share, they introduced Hi-Fi technology for Beta.  JVC followed
suit, could not use Sony's technology, so had to invent their own version
of Hi-Fi.  Sony devised the better technology in both cases, but in both
cases Hi-Fi had to be adapted to a pre-existing video record/playback system.
>
>And also, are you suggesting that VHS cassettes have a lifetime of 5-6
>years? What about al those videos in video rental outlets? WHere did
>you get this information that video cassettes will only last this long?
>
Video tape has long been known to be an unstable medium.  Many network video
tapes, recorded on 1" to 2" wide masters at faster speeds (15 to 30 inches
per second) and stored under careful conditions, have proven to be unviewable
after 20 to 25 years.  Home video, which records at much slower speeds and
narrower tape (1/2"), is far more susceptible to decay earlier on.  If you
truly wish the longest life for your home recordings, you should ALWAYS
record in 2-hour (SP) mode.  They'll degrade far slower than a tape recorded
at LP (6-hour) mode.  Careful storage techniques will help prolong the tape's
shelf life, but nothing will make them last into perpetuity.

Combine video's unique storage problems with the inherent problems of tape in
general (true of DATs, also) such as loss of lubricant, and loss of adhesion in
the tape to the metal particles that actually hold the recorded information,
and one is revealed to the sad fact that tape is not a long term reliable
medium for storage.

It's the only thing we've got for recording right now, so it'll have to do.
Pick your favorite media and do what you can to make the best of it. :-)

George Lambert