[sc-users] shelving filters

[Josh Parmenter]

The BEQSuite has a couple of nice shelving filters (part of sc3- 
plugins). BHiShelf and BLowShelf

Josh

On Feb 3, 2008, at 10:42 AM, Sam Pluta wrote:

> Hey all,
>
> I am trying the make a low shelving and a high shelving filter.  I  
> have taken the code that Mr. Harkins uses in his graphic eq and  
> attempted to make my own filters.  Sadly, I am unable to understand  
> why these don't work.  The math is beyond me.  Any help?  Just  
> another thought; shouldn't we have low shelving and high shelving  
> filters in the distribution?  That seems useful.
>
> Thanks in advance,
>
> Sam
>
> SynthDef("buchlaLowFilter", {arg inBus, outBus, freq, db;
> 	var in, amp, wc, coef, out;
>
> 	in  = In.ar(inBus, 2);
> 	
> 	amp = db.ampdb;
> 	
> 	wc = pi * freq * (1/44100);
> 	coef = (1 - wc)/(1 + wc);
> 	out = FOS.ar(in, coef.neg, 1, coef, amp.neg.sign);
> 	out = 0.5 * (in + out + (amp.abs * (in-out)));
> 	
> 	ReplaceOut.ar(inBus, out);
> }).writeDefFile;
>
>
> SynthDef("buchlaHighFilter", {arg inBus, outBus, freq, db;
> 	var in, amp, wc, coef, out;
>
> 	in  = In.ar(inBus, 2);
> 	
> 	amp = db.ampdb;
> 	
> 	wc = pi * freq * (1/44100);
> 	coef = (1 - wc)/(1 + wc);
> 	out = FOS.ar(in, coef.neg, 1, coef, amp.sign);
> 	out = 0.5 * (in + out + (amp.abs * (in-out)));
> 	
> 	ReplaceOut.ar(inBus, out);
> }).writeDefFile;
>
>
> spluta at gmail.com
> www.sampluta.com
> myspace.com/sampluta
> myspace.com/exclusiveor
> myspace.com/glissandobinladen
>
>
>
>
>
> _______________________________________________
> sc-users mailing list
> sc-users at create.ucsb.edu
> http://lists.create.ucsb.edu/mailman/listinfo/sc-users

******************************************
/* Joshua D. Parmenter
http://www.realizedsound.net/josh/

“Every composer – at all times and in all cases – gives his own  
interpretation of how modern society is structured: whether actively  
or passively, consciously or unconsciously, he makes choices in this  
regard. He may be conservative or he may subject himself to continual  
renewal; or he may strive for a revolutionary, historical or social  
palingenesis." - Luigi Nono
*/

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