I agree with George that a plug-in would be preferable if the emulation can be achieved.

One big advantage of a plug-in is that decoding wouldn't need to take place in real-time, so there 
can be a constant re-evaluation of perameters and tweaking of things like levels and amount of 
expansion in a given frequency band. You could theoretically make the Dolby decoding much more 
transparent, thus making the NR itself more transparent. You could also unlock creative possibilites 
for those who want to mess with the Dolby expansion curves, frequency bands, etc, to get a 
"personality" from the tracks that they desire.

For Hollywood, I would think a Dolby plug-in would be very helpful for workflows in the preservation 
and restoration end of things, one less piece of hardware to worry about, one more process that can 
semi- or fully-automated.

Given the sophistication of compressor/limiter emulations already available in the plug-in world, 
I'd think a Dolby emulator is possible. But, as I said earlier, I think anyone who's actually used a 
Pultec EQ unit or a Fairchild compressor will tell you that the plug-ins aren't identical in 
performance, parameters, controls or results to the real thing. So perhaps the software science 
isn't there yet for something mission-critical like Dolby decoding.

-- Tom Fine

----- Original Message ----- 
From: "George Brock-Nannestad" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 11, 2012 9:13 AM
Subject: Re: [ARSCLIST] Dolby Plugin


From: Patent Tactics, George Brock-Nannestad


Hello,

I must confess that I am very surprised at learning that there is no
emulation of Dolby A available for the digital domain. The reason is
something Dolby said the during the discussion following Ray Dolby's Richard
C. Heyser Memorial Lecture at the 112th AES Convention in Amsterdam 2002.
Precisely because of this problem I asked about emulation, and Ray claimed
publicly that such products had been developed. Now, that is almost 10 years
ago, so I find it scandalous it that is not true.

We are always told that modern digitization is oh, so transparent, so I
cannot see any reason why Dolby A decoding could not occur in the digital
domain, in which there are no problems with levels and calibration, provided
the averaging needed for evaluating the level of the signal in a given
frequency range and hence the amount of processing is done correctly. And if
you have transferred your tape once, you should not need to do it ever again,
except for magnetical reasons, such as better heads and transports.

Best wishes,


George



Tom Fine wrote:

> I agree that this is proper procedure, always better not to D-A/A-D if
> possible. Consider it more
> direct signal chain -- original tape>Dolby decoder>A-D converter.
>
> However, I think the original poster said he did not have the original tape
> on hand, in which case
> the only good option is -- D-A converter>Dolby decoder>A-D converter.
>
> For what it's worth, I've experimented with both methods, using nothing too
> fancy, just my DAL
> CardDeluxe interfaces. There are slight audible differences, but they are
> subtle, to my ears. I
> can't say one sounds "better" than the other because they are so similar.
> It's possible that the
> tape>Dolby>ADC method sounds slightly more "open" but it's really a subtle
> difference. Conversion
> was done at 96/24 both ways. This is not a clearly audible difference, like
> between a 7.5IPS
> quarter-track tape and the same material recorded at the same time on a
> 15IPS 2-track tape, or
> between an LP and a master tape.
>
> -- Tom Fine
>
> ----- Original Message ----- 
> From: "Andrew Hamilton" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, January 11, 2012 7:26 AM
> Subject: Re: [ARSCLIST] Dolby Plugin
>
>
> Reads as if it's time for a fresh tape to ADC transfer with the Dolby in
> line.  Even using very good converters (e.g., Lavry Gold] in double
> signal-jacking [D/A/D] mode is counter-indicated unless you must do that
> to
> use some outboard analog processing.   If you have the tape, you don't
> have
> to do that.  It should not have been transferred without Dolby decoding.
>
>
>
>
> Andrew
>
>
> On 1/11/12 5:48 AM, "Tom Fine" <[log in to unmask]> wrote:
>
> > I agree with Ted. Dolby is a "process" (they themselves called it a
> "process"
> > in numerous marketing
> > materials), really it's a compressor and band-filter and expander. So
> it's
> > just another piece of
> > outboard equipment. I think a musician or producer that has access to a
> > real-deal good-working-order
> > Pultec EQ unit or Fairchild compressor would never use a "plug-in"
> instead.
> > Modelling is only so
> > good, it's modelling instead of actual hardware. The sound is bound to
> be
> > different, by varying
> > degrees (good modelling = slight differences due to slightly different
> > performance characteristics
> > in the real world; poor modelling = little resemblence to the real
> thing).
> > Dolby made and makes good
> > hardware, when used properly it's fine to run a source through a Dolby
> unit,
> > the result will sound
> > better than un-decoded.
> >
> > -- Tom Fine
> >
> > ----- Original Message -----
> > From: "Ted Kendall" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Wednesday, January 11, 2012 4:03 AM
> > Subject: Re: [ARSCLIST] Dolby Plugin
> >
> >
> >> On 10/01/2012 21:51, Richard L. Hess wrote:
> >>> Hi, Louis,
> >>>
> >>> Your wishes are the same as the rest of us...but I'm afraid you'll have
> to
> >>> hold your nose and go
> >>> out to the outboard Dolby A unit and then back into digital.
> >>>
> >>> I wish I were wrong, but Dolby has been pretty insistent that they
> don't
> >>> want to do this.
> >>>
> >>> Richard
> >>>
> >>> On 2012-01-10 3:14 PM, Louis Hone wrote:
> >>>> Greetings
> >>>>
> >>>> A client brought me a WAV file which is a direct transfer from a
> quarter
> >>>> inch tape (1980). The tape had a full set of tones (15 K, 10 K, 1K,
> 100,
> >>>> 50, and Dolby A warble tone) and these tones are in the WAV file. The
> >>>> original tape was Dolby A encoded and the WAV file has not been
> decoded. I
> >>>> know that whoever did the transfer, adjusted the azimuth, as well as
> high
> >>>> and low frequency EQ prior to the transfer. However, no Dolby A unit
> was
> >>>> available so the tape remains encoded. My question: is there a Dolby
> A
> >>>> plugin that can be used in ProTools ? I wish to avoid going back to
> the
> >>>> analog domain (and through a Dolby A unit) and back to digital in order
> to
> >>>> decode this file.
> >>>>
> >>>> Thanks
> >>>>
> >>>> Louis Hone
> >>>>
> >>>
> >> What's the problem with going through analogue? Transparent conversion
> has
> >> been available for some
> >> time now, and the vagaries of modelling would be far more likely to
> cause
> >> problems than another
> >> stage of conversion.
> >>
>
> -- 
> Serif Sound  CD Premastering
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