[ProAudio] FeralA - Recordings released encoded with Dolby A

[Corey Bailey Audio Engineering]

Hi Richard,

Of the mastering houses that I worked with during the 1970's (& I worked 
with several), I never saw or heard of a reference document regarding 
noise reduction. Both Scott Dorsey & Bob Olhsson referred to using Dolby 
A as an effect. Back in the day, I generally avoided noise reduction 
when recording to multitrack tape. I could hear the difference or, at 
least, I thought I could. That said, I used to routinely encode travel 
cassettes & then play them un-decoded in the car because the extra HF 
would help cut through the road noise.

Regards,

Corey

Corey Bailey Audio Engineering
www.baileyzone.net

On 2/9/2020 9:32 AM, Richard L. Hess via ProAudio 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
>
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