hi,
i'm trying to use a bp~ object so that it can filter frequencies betweem Fmin and Fmax.
i think the central frequency should be set to ( Fmin+Fmax )/2, but what value should be given to the Q factor ??
thanx.
yves/
On Mon, 3 Jun 2002, Yves Degoyon wrote:
hi,
i'm trying to use a bp~ object so that it can filter frequencies betweem Fmin and Fmax.
i think the central frequency should be set to ( Fmin+Fmax )/2, but what value should be given to the Q factor ??
assuming that you consider Fmin and Fmax to be the -3dB cutoff points, then the formula should be: Q = Fcenter/(Fmax-Fmin)
-dan
thanx.
yves/
PD-dev mailing list PD-dev@iem.kug.ac.at http://iem.kug.ac.at/cgi-bin/mailman/listinfo/pd-dev
Hi yves.
Q is the quality factor of the filter.
the more you increase Q, the more the filter will be sharp.
This mean that if Fmin is very close to Fmax, your filter will give you a very strong atenuation when you will be outside your (Fmin-fmax). If Fmin is far from fmax, your filter will be flat, so it won't filter anything.
If you whant to have always the same atenuation (eg 18dB/octave) what ever Fmin and Fmax, you must use a lowpass filter combinated with a higth pass one.
I hope this is clear. If it's not, please contact me again.
Cheers, Damien.
Le Lundi 3 Juin 2002 00:48, Yves Degoyon a écrit :
hi,
i'm trying to use a bp~ object so that it can filter frequencies betweem Fmin and Fmax.
i think the central frequency should be set to ( Fmin+Fmax )/2, but what value should be given to the Q factor ??
thanx.
yves/
PD-dev mailing list PD-dev@iem.kug.ac.at http://iem.kug.ac.at/cgi-bin/mailman/listinfo/pd-dev