@solipp I was wondering if fft-split~ could be used as an upsampled anti-aliasing filter but I'm not getting the results I expected. Things seem to change radically depending on the oversampling factor. What am I misunderstanding?
fft-split~ as antialias filter.pd
EDIT: NEVERMIND
It appears that Pd doesn't perform the 4X overlapped FFT windowing as expected if the FFT's block size is smaller than 4X the block size of the enclosing patch. When I change fft-split~'s block size to 4096, things are fine. But let me know if I've given the wrong reason.