[Csnd] Bandpass and notch through lowpass and highpass (parameter questions)
| Date | 2017-11-15 21:08 |
| From | "Jeanette C." |
| Subject | [Csnd] Bandpass and notch through lowpass and highpass (parameter questions) |
Hey hey,
my understanding is, that both bandpass and bandreject or notch filters can be
created by lowpass and highpass filtering a signal in series or in parallel,
respectively.
My question: how is the q parameter for the resulting filter adjusted? Is it
the distance of cutoff frequencies or a change in q-values for the two filters
or a combination thereof?
If the answer can widely vary, I'm most interested in the answer as would
apply to a typical analogue statevariable filter model, as found on a
Steiner-Parker filter or in Csound the zdf_2pole or statevar. Alas, my code
reading skills are insufficient for an unassisted explanation.
Best wishes and thanks for any help,
Jeanette
--------
* website: http://juliencoder.de - for summer is a state of sound
* SoundCloud: https://soundcloud.com/jeanette_c
They say, break away - I'm missing out on the fun and games <3
(Britney Spears)
Csound mailing list
Csound@listserv.heanet.ie
https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
Send bugs reports to
https://github.com/csound/csound/issues
Discussions of bugs and features can be posted here |
| Date | 2017-11-15 21:15 |
| From | Victor Lazzarini |
| Subject | Re: [Csnd] Bandpass and notch through lowpass and highpass (parameter questions) |
|
I guess it depends on the filter, but for resonant lp and hp, the Q value generally is to do with the resonance region, so it would not set the bandwidth of a combined filter,
but the separation of the cutoff freqs will.
What the Q of the individual filters would change is the resonance peaks at the edge of the pass/stop band.
Victor Lazzarini
Dean of Arts, Celtic Studies, and Philosophy
Maynooth University
Ireland
|