julien.breval@tremplin-utc.net wrote:
Actually, I am making a kind of brick-shaped band pass filter,
For true brick shape, use series higher order filters. The full iemabs lib has 2nd through 10th order butterworth and other filters available. Make your cutoff frequencies track as well.
[r audio] | | [r cf] | [/ 1.2 ] | | [hp10_butt~] | | [r cf] | [* 1.2] | | [lp10_butt~]
as an alternative to [vcf~] which has a triangular shape. If this kind of filter already exists in a library, I will use it but I haven't found anything yet. The first solution is to use first a series of [lop~] and to pass it into a series of [hip~]. I still have some DSP problems with all this when I change the frequencies (I got surprisingly high levels sometimes). Maybe another solution is to use a kind of narrow filter bank using some [vcf~], but it's not very easy to control as I would need lots of filters, like in FFTs. The FFT is not a good solution here either, because time precision is very important.
I may want to change the cutoff very fast, with big jumps
hmm, this is worrying then. Are there not any low-pass or high-pass filters in the latest iemlib that take signal inputs for the cutoff freqs? I'm sorry, I haven't got Pd
here
at work, so I can't check. But I must say I HAVE noticed clicks even
using
the control (ie. non signal) version of [line].
that's what I feared actually
I think my block size was 64, but whatever this value is the output from [line] will always be a significant jump compared to using [line~] - unless you make the [line] change REALLY slowly of course!
I will try to use [line] with a very small time grain
thanks for your help
-j