[PD] 2 Q's: env~ and decimation

[matthew jones]

Hi list!
Two questions, completely unrelated:

(1) How does env~ work?  Does it just calculate the root mean square of all
values in the input buffer, of user defined size (by just summing each
number and adding), or does it use the recursive running sum (RRS)
implementation?  I'm doubting it uses RRS since you increase the time
averaged over, and the frequency at which output is sent DECREASES.  This
would not be logical in an RRS scheme whereby with one delay and a one tap
IIR filter you could get an envelope output at signal rate, independent of
sumation interval.

(2) Is there a way to decimate in Pd?  I recently went to a fantastic
lecture on subband filtering, and would like to see if I can implement such
an algorithm in Pd.  I seem to remember filters with complex coefficients
are implementable, but without decimation the advantages to subbanding are
lost.

Matt

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