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Compression maybe with sidechain

Posted: Mon Jan 13, 2014 8:48 am
by rasmus
Is there any good compression codes out there? Maybe with an input for sidechain.

I know that there are some limiters among the Free DSP programs, but all the programs from Keith Barr doesn't have any description of what the three POTS controls.

How can I see from the code what the potentiometers will control?

Thank you

Posted: Mon Jan 13, 2014 10:22 am
by frank
It doesn't look like Keith used the POTs for any control, the limiters he put up were all fixed in function. I suggest you read the knowledge base about level detection and continue down that page into limiters, etc. He explains things there, see http://www.spinsemi.com/knowledge_base/ ... _detection

Posted: Sun Jan 26, 2014 4:02 pm
by Mcfly
Regarding this limiter code, is there any way to make the threshold variable with a pot?

Code: Select all

equ sigin reg0	
equ avg reg1	 
rdax adcl,0.5	 
rdax adcr,0.5	 
wrax sigin,1	 
mulx sigin	 ;square
rdfx avg,0.001	 
wrax avg,1	;average
log 0.5,0	;[square
exp 1,0	;root]
log -1,-0.125	;[1/X, set thresh @2 bits (2/16ths)
exp 1,0	;]
mulx sigin	;gain reduce
sof 1.5,0	 ;restore level
wrax dacl,1	 
wrax dacr,0

Posted: Mon Jan 27, 2014 5:51 pm
by Digital Larry
Regarding this limiter code, is there any way to make the threshold variable with a pot?
Off the top of my head, I would add a MULX POTx after the "average" line and before the "square" line. You might need to boost the level a bit before the MULX POTx there to give you room to bring it down.