Ok, so if pulse audio is required and installed, I would go ahead and install pavucontrol: Code: sudo apt install pavucontrol After it's installed, open the software you want to use and verify it is working (for example, CubicSDR) - make sure that it is "on" and producing audio (or at least looks like it is). Then you open the pavucontrol gui and click on the "playback" tab and you should see CubicSDR listed there, and there should be a little VU meter thats pulsating along with the output of the sofware. Next to it should be a dropdown menu with various audio output methods - you should be able to select your bluetooth output or the USB soundcard. Play around with the other tabs in pavucontrol as it allows you to pipe the audio into other software as well as set the levels (volume) for each individually. On Ubuntu, the "system" volume control that is located in the upper right hand corner of the desktop is rendered useless with pulseaudio, and I suspect this is true with the Raspi, as well (which could explain why it isn't working for you).  I should point out that in Ubuntu, at least, pavucontrol seems to "remember" the settings for various programs and hardware - so generally I only have to do this once. This can cause problems, however, as sometimes I forget to turn my Signalink off, and it takes the general audio from the system and tries to Tx it from my 706MKIIG. The last time this happend, I was "calibrating" QSSTV and during the Tx portion of the calibration, my radio was keyed for like 10 minutes as I was outside mowing the lawn or something.... thankfully there was no actual audio so the Tx output was very close to zero watts (rig was in SSB on 14.230, not FM) - but still something to keep tabs on.