Re: [linux-audio-dev] Paper on dynamic range compression

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To: The Linux Audio Developers' Mailing List <linux-audio-dev@...>
Date: Thursday, October 5, 2006 - 6:03 pm

On Thursday 05 October 2006 14:09, John Rigg wrote:

Which is why one of the best compressors of all time, designed by CBS Labs
back in about 1960, was so good. It had 2 versions for two different
broadcast scenarios, one for the 75u-s pre-emphasis of fm, and one that
was flat for am. But both had 2 circuits, with the faster circuit having
microsecond response times to control the peaks while allowing a fairly
high average. I'm refering of course to the Volumax and Audimax devices.
Some of those are still in service, hidden away at transmitters in your
neighborhood. The single vacuum tube they used in one of them, a
'nuvistor' has probably long since been replace by a depletion mode fet
transistor and the device recalibrated back to factory specs. And all the
2 uf electrolytic capacitors used in the original have long since been
replaced with 2 uf mylars. At that point, you can literally forget its in
there, for years at a time.

You couldn't hear it working unless the next audio source switched to was
-30db from the previous one, then you could hear it slowly raisng the gain
for several seconds, eventually picking up a peak that opened the high
speed gate and 100ms later the sound was at the normal level again. All
without the sleeping dj ever knowing he wasn't doing his job on the board.

Anything else we attempt to put in there just seems to bring back memories
of that 5 minutes of heavy breathing from last night, just before you went
to sleep...

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.

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Messages in current thread:
[linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Thu Oct 5, 3:50 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Alfons Adriaensen, (Thu Oct 5, 8:46 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Thu Oct 5, 1:44 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Thu Oct 5, 2:01 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Fri Oct 6, 2:25 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Gene Heskett, (Thu Oct 5, 6:03 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Thu Oct 5, 2:14 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Alfons Adriaensen, (Thu Oct 5, 3:29 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Fri Oct 6, 2:48 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Fons Adriaensen, (Thu Oct 5, 5:05 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Erik de Castro Lopo, (Tue Oct 17, 9:18 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Erik de Castro Lopo, (Tue Oct 17, 10:28 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Jens M Andreasen, (Wed Oct 18, 5:23 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Erik de Castro Lopo, (Wed Oct 18, 8:50 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Fons Adriaensen, (Wed Oct 18, 11:33 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Fons Adriaensen, (Wed Oct 18, 4:35 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Erik de Castro Lopo, (Wed Oct 18, 11:21 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Steve Harris, (Wed Oct 18, 11:08 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Steve Harris, (Wed Oct 18, 10:42 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Paul Winkler, (Tue Oct 17, 11:00 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Steve Harris, (Wed Oct 18, 10:58 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Fons Adriaensen, (Tue Oct 17, 9:54 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Fons Adriaensen, (Tue Oct 17, 2:41 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, David Olofson, (Tue Oct 17, 4:51 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Fons Adriaensen, (Tue Oct 17, 5:05 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Dominique Michel, (Wed Oct 18, 3:40 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Steve Harris, (Wed Oct 18, 10:54 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Steve Harris, (Tue Oct 17, 12:06 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Alfons Adriaensen, (Fri Oct 6, 9:00 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Alfons Adriaensen, (Thu Oct 5, 2:22 pm)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Fri Oct 6, 3:47 am)
Re: [linux-audio-dev] Paper on dynamic range compression, Andres Cabrera, (Fri Oct 6, 2:31 pm)