i recall a conversation years ago with michael gerzon about
decoders, both dolby and dbx. he explained why it was not really
possible due to bandwidth issues; not accurately enough, probably due
to frequency warping with digital EQ (as it approaches nyquist).
<that is my supposition, and when it came to gerzon, i was not
usually right, but if i find the email where he told me, i'll share
as far as not being able to do it: i'm not sure that's the case
anymore, but Dolby has a very good reason to not do it, even if they
could: piracy. there is a constant battle against faceless deviants
bound to break protection, far more than physical heists of audio
gear. if you made gear and had that many people trying to steal it,
you'd give up, of course. UA ties their processors to an embedded
co-processor, which makes it secure; this is a military-grade
approach. waves has used various methods, all of which eventually
have been broken. it is very tiring and costly to protect the
possible ROI on DSP development.
modeling has advanced so significantly in the past few years that any
prior experience with it needs an update. of course, some models are
better than others. most software processing companies prefer to have
"incredible" graphics and anonymous algorithms rather than do it
right (i.e., pay the money for the top shelf DSP experts).
At 15:13 +0100 1/11/12, George Brock-Nannestad wrote:
>From: Patent Tactics, George Brock-Nannestad
>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.
>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
>> to do that. It should not have been transferred without Dolby decoding.
>> 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
>> > in numerous marketing
>> > materials), really it's a compressor and band-filter and expander. So
>> > 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"
>> > Modelling is only so
>> > good, it's modelling instead of actual hardware. The sound is bound to
>> > 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
>> > Dolby made and makes good
>> > hardware, when used properly it's fine to run a source through a Dolby
>> > 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
>> >>> 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
>> >>> 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
>> >>>> inch tape (1980). The tape had a full set of tones (15 K, 10 K, 1K,
>> >>>> 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
>> >>>> and low frequency EQ prior to the transfer. However, no Dolby A unit
>> >>>> available so the tape remains encoded. My question: is there a Dolby
>> >>>> plugin that can be used in ProTools ? I wish to avoid going back to
>> >>>> analog domain (and through a Dolby A unit) and back to digital in order
>> >>>> decode this file.
>> >>>> Thanks
>> >>>> Louis Hone
>> >> What's the problem with going through analogue? Transparent conversion
>> >> been available for some
>> >> time now, and the vagaries of modelling would be far more likely to
>> >> problems than another
>> >> stage of conversion.
>> Serif Sound CD Premastering
>> Dingbat Lacquer Sound Disc