It took a couple days for your suggestion to sink it (possibly) > On Apr 25, 2023, at 9:19 PM, Ariadne Lewis-Towbes <a...@towb.es> wrote: > > Hi, > > You won't be able to fade between two filtered blocks of complex > (non-sinusoidal) input to the same effect as modulating an arbitrary single > filter's frequency. That said, when modulating an IIR filter such as a biquad > (as shown in your second email's link), you should not need to compute the > z-transform. You may simply modulate the biquad's parameters repeatedly,
By this you mean compute biquad parameters for start and ending freq, then incrementing the a0, a1 etc? > and unless you're doing something unusual with respect to calculating those > parameters, the cost will be relatively low. > > Best, > Ariadne Lewis-Towbes > >> On 2023-04-25 20:37, Yisheng Jiang wrote: >> I’m trying to render a note that feed into a IIR filter (2-3 poles) >> whose cutoff frequency following an envelope generator, and it’s not >> possible for me to compute the z-transform parameters every rendering >> block.. >> Is it approximately the same to generate two pcm streams with the >> starting and ending cutoff frequencies, then cross fade them to make >> the resultant sound?
