Some ideas for compressor side-chains

[JohnRoberts]

http://www.google.com/patents/US5133015

see schem on p.5 - around the fet there are diode string doing the "voltage dependent resistance".

The whole thing is tailored towards specifics of guitar signal, so don't second guess the validity of this approach within this context - it was tweaked to the max. This may therefore not work "as expected" on your music programme material.

claim 1 a variable means for creating distortion...

??

JR

 

[tv]

yes, this is it, as I said. don't be fooled by appearances...

there's a "compressor inside"

 

[JohnRoberts]

yes, this is it, as I said. don't be fooled by appearances...

there's a "compressor inside"

From the claim language it appears any compressor inside is not part of the protected IP.

JR

 

[tv]

... not so fast ...

Abstract

An electronic audio signal processor especially suitable for electrical instruments such as electric guitars is provided, including a distortion stage, filtering stages, an output gain stage, and a compressor stage having a varibale release time. These stages are provided in a cascade connection. Further, the characteristics of each of these stages are preset to provide optimum performance at each of several different distortion levels. The correct characteristics of each stage for each distortion level is selected by means of a single user control.

....
blah blah
....

means responsive to said indicating means for controlling the degree of distortion caused by said distortion means, said distortion means having an output volume which varies in a predetermined way as the degree of distortion increases; and

output means responsive to said indicating means for automatically, and without further user input, maintaining the volume of the audio signal output from said circuit substantially at a desired level regardless of the degree of distortion caused by said distortion means.

It's an integral part - the heart - of his process.

 

[JohnRoberts]

but his process is primarily a distortion effect with some dynamic level dependent interactions ...  not a compressor, which generally tries to alter dynamics without adding distortion, while some designers seem to embrace distortion.  :

My understanding of this thread is to minimize audible artifacts, not add them.

If you want to make a rockman that seems like a different task.  FWIW the priority data of 1990 on the patent means it is now public domain so you can freely copy that if you wish.

JR

 

[tv]

.. well we certainly copied rockman ideas when it was "hot" ... and there were japanese commercial clones cheap to buy ... and mod. the one I got was a real ***** to disassemble

... while the point is there is a wicked gain cell at the heart of his processor.

of course it's tweaked to work in a guitar processor (rockmans were also famous for their "clean" setting), but that doesn't change the fact that it's a wicked gain cell, designed and tweaked to withstand some fairly demanding performance requirements (google if you're interested) ... just saying,  the rockman "fame" was supposedly earned in the field not created with media advertising ... so there must be something special about it, haha

hey! i've been censored!

 

[L´Andratté]

Same thing explained for morons like me

http://www.rockman.fr/Reviews/GC.htm

 

[gyraf]

Thanks for bumping - very interesting thread.

I'll add that the NTP 179-160 compressor also does some pretty interesting things in the sidechain - including some low-frequency-dependent recovery delay and possibly also zero-crossing gainchange (not looked too much into that part yet)

http://www.gyraf.dk/schematics/NTP_179-160_Compressor.PDF

IMO this is one of the few that competes with the GML on the transparancy-scale.

Jakob E.