[pulseaudio-discuss] Mixing midi output and microphone to conferencing app

[Jan De Luyck]

Hi folks,

I'm trying to send the output of an usb-connected plantronics headset and my digital piano (using midi + fluidsynth) over google meet/zoom/jitsi/.. to the other side. I also  need to hear my piano in the headset (it has no speakers)

I've based myself off of https://unix.stackexchange.com/questions/576785/redirecting-pulseaudio-sink-to-a-virtual-source and been testing all kinds of combinations, but I'm hitting a roadblock.

The commands I'm using at the moment are:

HEADSET="alsa_output.usb-Plantronics_Plantronics_Blackwire_3225_Series_1129BBD004004FF4BD2E6F2248C0D73E-00.analog-stereo"
MIC="alsa_input.usb-Plantronics_Plantronics_Blackwire_3225_Series_1129BBD004004FF4BD2E6F2248C0D73E-00.analog-stereo"

pacmd load-module module-null-sink sink_name=mix-for-virtual-mic sink_properties=device.description=Mix-for-Virtual-Microphone
pacmd load-module module-combine-sink sink_name=virtual-microphone-and-speakers slaves=mix-for-virtual-mic,$HEADSET
pacmd load-module module-loopback latency_msec=20 sink=virtual-microphone-and-speakers source=$MIC
pacmd load-module module-null-sink sink_name=silence sink_properties=device.description=silent-sink-for-echo-cancel
pacmd load-module module-echo-cancel sink_name=virtual-microphone source_name=virtual-microphone source_master=mix-for-virtual-mic.monitor sink_master=silence aec_method=null source_properties=device.description=Virtual-Microphone sink_properties=device.description=Virtual-Microphone

The effect is that I can perfectly pick the microphone "Virtual Microphone" in the conferencing apps, but only my keyboard is sounding through. My voice / mic never gets picked up.

I've tried recording using 
parecord --channels=2 -d mix-for-virtual-mic.monitor /tmp/x.wav 

but same story, only the piano is being picked up.

What did I miss? In all logic, this should work?

Kind regards,

Jan