I fixed my filterbank trouble. You were right when you said that one
needs to connect EVERYTHING. For instance, let’s say you channelised
a signal into 20 channels and you wanted to write channel 5’s output
to a file. Then you need to connect channels 0-4 to a null sink (or
whatever), as well as channels 6-19. My previous mistake was to not
connect the higher channels to something. This results in a correct
output when looking at channel 0 and junk outputs for the rest.
Thanks for all the other help.