thanks marius, dave. good ideas. just one extra thing (unrelated)
how do you implement an FIR/IIR filter? do you need a 'delay-by-one-sample' patch or is there a more direct route? also, do you have to have a blocksize of one sample?? for an adaptive filter it would be nice to update the filter every new sample, and also use it every sample coming in (I'm guessing with a blocksize of, say, 64 that you only get access to the inputs every 64 samples??)
(hope I'm not filling everyones inbox too rapidly) M