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From: JED@SU-AI.ARPA (Jim Davidson)
Newsgroups: net.video
Subject: audio comparison of VCR formats
Message-ID: <8603152235.AA14398@seismo.CSS.GOV>
Date: Sat, 15-Mar-86 17:33:00 EST
Article-I.D.: seismo.8603152235.AA14398
Posted: Sat Mar 15 17:33:00 1986
Date-Received: Mon, 17-Mar-86 03:20:12 EST
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Organization: The ARPA Internet
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The April "Stereo Review" has the results of a comparison test between
Beta Hi-Fi, VHS Hi-Fi, and 8mm.

General conclusion: as an audio recording medium, VCR's don't quite 
cut it, especially compared to the original descriptions of near-CD
quality.  But, they're still pretty good.

First, the structure of the test: ABX double-blind.
Under this method, a reference signal (X), is compared to two other
signals, A & B.  One of A or B is equal to X.  The test checks
whether the listener can reliably tell which one is the same as X
(and if there is a difference, which is preferred).

SR ran a similar test a few months ago, on CD players.  Conclusion was
that, using music (as opposed to test signals), listeners could *not*
consistently distinguish between CD players.

Things were different here.

Listeners could distinguish between the formats, and had things to say
about all of them.  The overall conclusion was that all three formats had
problems. The listeners, who didn't know what the sound sources were,
thought that in some cases they were listening to turntables (?!).

The machines: JVC VHS; Pioneer Beta (presumably Sony-made); Sony 8mm.

The three formats were compared to each other, and to a reference signal
recorded with an outboard PCM module.  Listeners could reliably pick
out the reference signal, and preferred it to the others.

Regarding direct comparisons between the formats:

8mm was noticeably different from the others (not suprising, since it's
missing the high end), but was felt by some to be "smoother".  VHS & Beta
were felt to be brighter than 8mm but had other problems (such as
mechanical noise).

VHS was preferred over Beta, although the latter was said to do better
on transients.

SR also did some electronic testing, to check out the differences.  VHS
came out of this the best: flat response over the whole range.  8mm, of
course, disappears above 15kHz.  Beta started to roll off at about 11KHz,
and was slightly down over most of the high end.

The listeners were surprised when they were told of the sound sources;
a number of them were Betaphiles.  

The conclusion was that VCR audio will not replace reel-to-reel tapes.
On the other hand, the music in the tests was selected in part to show up
the problems and differences in the formats.  For a lot of material, or in
less-than-studio conditions, this just isn't noticeable.  Also, many of
the listeners owned hi-fi VCR's, and said that the problems didn't seem
significant when they were watching a video.  (This has been my
impression.)  Finally, of course, hi-fi audio beats the pants off linear.