posted 20 August 2005 16:02            

Where should I go for a single band notch filter? It seems like if I was smarter, I woud look at the BandPassFilter prototype and figure out how to make it into a BandRejectFilter by myself, but am I overlooking something else?

On a related note, I was trying to look at the EQs on the Tweaky, and have downloaded David McClain's microsounds file, but I don't know what to do with the microsounds so that the EQ's will run (those that require the microsounds in the first place). It has a ".asy" file type. What is that? I don't see any other .asy files in the Kyma folder.

Thanks again for your patience...

Phil

posted 20 August 2005 16:49            

2-PoleFilters.kym

The BRF filter is a Band-Reject-Filter, or Notch. But there are many other ways to build a notch filter too. For example, just cascade a low-pass filter with a high-pass filter, and make sure to spread their cutoff frequencies so that the LPF has a lower cutoff than the HPF.

All of the Sounds in this soundfile rely on my microsounds to do the DSP work. But in actual fact, you could completely synthesize all of these filters using standard Sound blocks in Kyma, and using the coefficient computations shown in these DSP processing blocks.

On the Mac you have to place the microsounds in the Kyma folder and name it "User Microsound Classes.asy". I can't remember offhand how to do it on the PC...

posted 20 August 2005 19:09            

testfilt.kym

quote:

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Originally posted by David McClain:
For example, just cascade a low-pass filter with a high-pass filter, and make sure to spread their cutoff frequencies so that the LPF has a lower cutoff than the HPF.
- DM

---

I was thinking about cascading filters a la the BandPass prototype but it seems little beyond my current capabilities. If I take the factory bandpass prototype, keep the same frequency definitions and simply make the highpass filter into a lowpass filter and the lowpass filter into a highpass filter, by my reasoning the frequencies that were overlapping and thus creating a bandpass should now be not quite meeting and creating a band reject (ie the lowpass now has a lower freq than the highpass). But it doesn't seem to be working out that way - I seem to just get another variation on a bandpass. The file is attached, if anyone wants to point out my mistake, which is probably something obvious.

Going back to your 2-pole filter examples, I can use them entering the variables, but I'm still a bit confused about the whole lifted-sound/environment concept. Oh well, back to reading the manual and learning more...

best,
Phil

posted 22 August 2005 13:48            

[It has often been said that the best mathematicians are very lazy people. They find the simplest possible approach to the problem. Obviously, I'm not in that camp...]