yes, I had seen that graphic as well. but trying out the highpass
iemfilters with noise, turns out that 10 hip~s work better.
I looked in my list of pd-ext objects, but found no elliptic filters. are
there any, or any way of getting their coefficients to use with biquad~?
chebychev filters look good, elliptic ones look better:
http://en.wikipedia.org/wiki/File:Electronic_linear_filters.svg