Damian Stewart wrote:
[shrug] i don't even know what a 'zero' is.
a (probably a little too simple) explanation:
a zero is a valley. its depth is 0 on its deepest point. a pole is a very (very,very,...) high mountain. both things exist on the complex plane (just a plain, where all points have 2 coordinates, like any map)
you can design filters by placing (defining a pair of coordinates) poles and zeros within the unit circle (a circle with radius==1 around the origin (center) of the complex plain). the frequencys from zero to samplerate/2 are wrapped around the upper half of the unit circle. when you cut along this line through your 'landscape', the profile is the same as the graph on your filter/eq plugin.
for example the peak-filter from the pd docs is just a 'mountain' and a 'valley' which are moved on circular pathes with a certain distance to the unit circle. the closer the 'mountain' is to the unit circle, the higher the peak (on the circular profile-cutout). the frequencys coressponding to this spot are boosted. the position on the path (or the angle) defines the frequency.
so it is possible to make filters with the cpole/zero objects, without knowing too much (or anything at all...) of the math involved.
the only problem i still have, is the gain-factor. while this is easy to overcome with 'static' filters (just scale the filters input or output until it is loud enough/stops clipping), i have not yet found a method (that works without thinking (and more important: computing) too much) for time-variable-filters. ok, a table would do the trick, but thats not elegant at all...
bis denn! martin