[ProAudio] FeralA - Recordings released encoded with Dolby A

[James Perrett]

I've been doing quite a few transfers of Dolby A encoded tapes over the
last few months and have tried a demo version of John's software one some
of them. The software has worked well once it is properly matched to the
audio. One thing that I notice is that the undecoded audio sounds similar
to a modern multiband compressed master - probably because that's pretty
much what it is. I wonder whether the decision to release the encoded
version was actually an artistic one rather than a technical glitch? On a
couple of releases I've actually gone the other way and used Dolby A
decoding as a fix for over-compressed mixes that I've received.

Most of the masters that I've transferred have been well labelled with
tones clearly marked - although there have been instances where the tones
weren't recorded at the same time as the master and were just tacked on
afterwards once the final mix had been chosen from (in some cases) 20
alternatives. In my experience there are an awful lot of alternative
masters sitting in the record companies' vaults and an unsuspecting record
label person could easily pick the wrong one to be used for a reissue. In
one case recently I was sent a production master for an 8 track cartridge
version of an album complete with fades halfway through songs - fortunately
they were also able to obtain the vinyl production master but I don't know
if they were able to find the original mix.

In the 70's I remember reading about a court case where one of the budget
labels (RCA Camden I think) was prosecuted for putting out a Dolby A
encoded recording without decoding it. I think it would have been in Hifi
News around 1974 but I don't know if I still have a copy here. I'm not sure
what prompted the prosecution but it would be almost unthinkable these days.

Cheers,

James.

On Sun, 9 Feb 2020 at 17:32, Richard L. Hess via ProAudio <
proaudio at bach.pgm.com> wrote:

> My colleague in the software decoder for recordings made with Dolby A
> noise reduction has been very interested in commercial releases that
> appear encoded.
>
> He has spent a good deal of time researching this. Thankfully, he's
> spared me most of the listening, but he's getting very good support from
> some online audiophiles, including one, I think, who writes for The
> Absolute Sound or something like that. I can hear the difference in the
> samples he sent me.
>
> The premise is that many albums were released without proper Dolby A
> decoding.
>
> I've been told this is the case for a few albums, including at least one
> recent re-release which was mixed undecoded from the Dolby A multitrack.
>
> What makes this more interesting is that he's finding a handful of EQ
> curves need to be applied to the recording prior to decoding.
>
> He has also found that many/most of these decode better as
> Sum/Difference (or MS).
>
> He thinks that there might have been a reference document in the
> mastering industry--it is that consistent.
>
> Does anyone know anything about this, or is it just happenstance?
>
> We don't think it's a common failure mode of old decoders--but it
> appears intentional.
>
> I know this sounds crazy, but there seems to be experimental support for
> this and the consistency of it is interesting.
>
> Does anyone know of any processes that were used in mastering back in
> the 70s that might create this. We don't think it's the Aphex Aural
> Exciter--that is a different kind of annoyance for my colleague. He has
> done some experimenting on a De-Exciter.
>
> Example artists are Linda Ronstadt, Olivia Newton John, and to some
> extent Abba.
>
> One of the reasons I've not attempted to shut down his FeralA
> experiments is that it has led to better finessing of the parameters and
> better decoding of real Dolby A recordings.
>
> Thanks!
>
> Cheers,
>
> Richard
>
> --
> Richard L. Hess                   email: richard at richardhess.com
> Aurora, Ontario, Canada           http://www.richardhess.com/
> http://www.richardhess.com/tape/contact.htm
> Quality tape transfers -- even from hard-to-play tapes.
>
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-- 
**********************************************************************
*       James Perrett
*       JRP Music Services, Hampshire, U.K.
*       Audio Mastering, Restoration, Recording and Consultancy
*       Phone +44 (0) 777 600 6107
* e-mail james at jrpmusic.net
* http://www.jrpmusic.net
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