I worked at Criteria in Miami, we had racks and racks of Dolby. They were
aligned every day for every session that used them, just as the machines
were. It wasn't difficult, although the most common error in-house was
getting distracted and making the adjustments in the wrong order. It was
enough that I provided a check list that was to be used by every studio tech
who came near them. Certainly we got tapes from other studios that could
show vastly messed up Dolby encoding. Usually I could make deliberate
mis-adjustments that would play those tapes reasonably well, but without
tones (WHO would send tapes without tones???) it could be a bit of a crap
shoot.
Scott
-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Tom Fine
Sent: Monday, January 17, 2011 5:15 PM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Dolby A-type level standards
Hi Fred:
This could well be the case, too. In any case, as long as I can get a good
playback, it's not a huge issue. When a tape without tones come in, that's
another matter. It's hard to believe that all professional studios that
could afford those Dolby units back in the day wouldn't have the expertise
to read the manual and set their machines accordingly, but apparently some
or many didn't.
-- Tom Fine
----- Original Message -----
From: "Fred Thal" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, January 15, 2011 12:58 PM
Subject: [ARSCLIST] Dolby A-type level standards
> Apologies if my following points have already been made by others. I
> only occasionally look at digest versions of this list.
>
> Tom Fine writes:
>
>> I've run into the same thing with Dolby A reels, with azimuth aligned
with a scope, the level-set
>> tones are sometimes lower than expected and in those cases it's great to
have Dolby tones to get
>> > the CAT22 to track well on decode. I've always ascribed this to
self-erasure over time.
>
> I think you are mistaken. There have always been differing standards
> for what constitutes Dolby level. It is hardly uncommon to see Dolby A
> encoded tapes recorded at different fluxivities.
>
> Regarding describing azimuth as being aligned with a scope, this is
> always somewhat ambiguous unless you also state whether you mean that
> two tracks were aligned for minimum inter-channel phase difference, or
> that one (or both) of those tracks were aligned for peak short
> wavelength amplitude response.
>
> Fred Thal
> Audio Transfer Laboratory
>
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