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Re: [ARSCLIST] Dolby B
At 12:04 PM 2007-10-26, Don Cox wrote:
There is a real need for a software Dolby decoder with adjustments,
because it isn't a simple matter of equalisation.
Indeed, Don, there is. I approached some people I know at Dolby with
this and went around and around. There is zero interest in this. They
still make the 422 for B/C/S and SR/A cards. They are expensive.
There is no ROI for the software plugin and there is substantial fear
it will be stolen--at least that is the impression I received.
Indeed, it is more than just equalization. As I said, I find it's
mostly level mis-calibration, so being able to adjust the level going
into the decoder is very important--why I use the outboard 422
instead of the inboard Dragon decoder for most things. It is possible
to also adjust EQ going into the decoder, but I've found that level
adjustments work well and there is a point that you can zero in on
with few to no "breathing" artifacts. This is why I suggest one hand
on the cassette deck output knob and one hand on the monitor level
control so you keep the levels constant in the room but you can tune
for minimum breathing.
If this doesn't work then applying a gentle lift in the DAW might be
of use. At some point, it makes sense to digitize undecoded and use
the digital proxy to run through the hardware decoder--there are more
tools available (for example, you can draw an EQ curve in an FFT
equalizer that you couldn't get close to with an Orban parametric).
I agree with Mike for access copies it's all about how it sounds. For
preservation copies, it might make sense to preserve the encoded
signal as well as the decoded signal--but I wouldn't preserve just
the encoded signal as that's putting more work on someone in the
future who may be less well equipped to deal with it.
Don't forget, we have:
Dolby A, SR, B, C, S
dbx I, II
Telcom C4, Nakamichi High Com II
Burwen companding in one or two flavours
This gets fun to look at the permutations. We have 10 items above. We
have 5 speeds and at least 7 different track configurations on
1/4-inch tape plus 5 on 1/2-inch tape plus 5 on 1-inch tape and at
least two on 2-inch tape for a whopping total of 19.
All the possible permutations are at least 10 x 5 x 19 or 950 --
let's round up to 1000!
This article outlines the types in a bit more detail
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/noise-reduction/
And this will bring up all of the items mentioning Dolby
http://richardhess.com/notes/index.php?s=dolby
and a couple that mention dbx not in the above
http://richardhess.com/notes/index.php?s=dbx
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.