[Discuss-gnuradio] Mixing multiple streams to audio

Hi --

I'm continuing to work on a multi-channel NBFM receiver using the
polyphase filter. I have the basic system working, but am hung up on
how to get audio out of the system; most of my attempts end up either
with audio underruns, or stalls that result in overruns.

The relevant portion of the flowgraph is attached. Each channel ends up
at a 15ksps rate and is fed into a power squelch, then a mult block
that's used to mute or unmute the audio, then NBFM demod. The
demodulated outputs are at 7.5ksps (though I get the same results with
15ksps) and the seven channels are added. Then a rational resample to
48ksps, volume control, and audio sink at 48ksps.

I've tried the "gate" param of the power squelch block both off and on,
and the "OK to block" option of the audio sink in various combinations,
but I'm not able to get clean audio.

I'd appreciate any suggestions. One thing I wonder about is the
placement of the blocks in the stream; would a different order work better?

Thanks for any assistance.

John