I've been periodically fussing over trying to construct a phaser (the effect, not the fictional weapon) and while there's a working ChucKian example at http://electro-music.com/forum/viewtopic.php?t=23264 , I'd like to understand more about what's going on. The example uses a PoleZero filter, which may as well be called PixieWand for all I know what it actually does. There are numerous other filter UGens as well; I think there may be a whole world of filtration out there I can't even imagine. The ChucK documentation doesn't provide descriptions of the mechanics of these filters. I get the impression that they're things you're expected to understand if you have a formal background in DSP, and if you don't, well, it's a bit of a leap to get there. For now I'm optimistic I can get educated in some way. A 2006 post on this subject on this list (https://lists.cs.princeton.edu/pipermail/chuck-users/2006-June/000763.html) suggested reading Real Sound Synthesis for Interactive Applications (http://www.amazon.com/Real-Sound-Synthesis-Interactive-Applications/dp/15688...) by Perry R. Cook. The book looks promising, but I'm not sure if it tackles the subject to a depth that would be helpful. Has anyone read it and could recommend? Perry, what do you reckon? =D Many thanks, Stuart