[PD] bandpass or resonant?

Tilo Kremer pd at dadacafe.org
Wed Jan 14 00:02:28 CET 2015


On 13.01.2015 04:20, Martin Peach wrote:
> I was looking at circuit diagrams for analog synthesizers recently and
> noticed that the "resonance" control is nothing more than feeding some
> fraction of the output back to the input. With more feedback oscillation
> occurs at the cutoff frequency for any type of filter, highpass, bandpass
> or lowpass.
> Martin

when i asked about the difference between the meaning of 'Q' in
filters regarding a parametric EQ on a mixing console and the
'Q'/Resonance knob on [analogue synthesizer] filters, i was given an
explanation along the lines of 'Q on a parametric eq will adjust the
bandwith of the filter while the Q / resonance knob on the other one
will adjust the amount of the feedback [back into its input]. Both
however will have a similar impact:
Reducing the available bandwith will lead to similar results as
increasing the amount of "data" in the system.'

hope that isn't too simplified, if it is, i recommend watching Aaron
Lantermans lectures on filters on the web.


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