Setup Pulseaudio modules to merge a mic and an application for input #script

setup-shared-audio.sh

# Enter your input and output device names here
source=bluez_source.98_09_CF_F3_12_0F.headset_head_unit
sink=bluez_sink.98_09_CF_F3_12_0F.headset_head_unit

# Module names
sharednull=shared-null-sink
sharedsink=shared-sink
sharedsource=shared-source

# Cleanup devices left over from prior runs
{
  pactl list short modules | grep $sharednull | cut -f1 | xargs -L1 pactl unload-module
  pactl list short modules | grep $sharedsink | cut -f1 | xargs -L1 pactl unload-module
  pactl list short modules | grep $sharedsource | cut -f1 | xargs -L1 pactl unload-module
} &> /dev/null

# Check if both input and out devices exist
if [[ $(pactl list sources | grep -e $source | wc -c) == 0 ]]; then
  echo "Input device '$source' not connected"
  exit 1
fi
if [[ $(pactl list sinks | grep -e $sink | wc -c) == 0  ]]; then
  echo "Output device '$sink' not connected"
  exit 1
fi

{

    # Create the null sink and loopback the input source into it
    pactl load-module module-null-sink sink_name=$sharednull
    pactl load-module module-loopback source=$source sink=$sharednull

    # Create a virtual sink that splits all audio towards both the microphone sink and the output sink
    # Pipe any app you want to share with your input to this sink
    pactl load-module module-combine-sink slaves=$sharednull,$sink sink_name=$sharedsink sink_properties="device.description=Shared-Sink"

    # Create a virtual source monitoring the microphone sink to use within any app where you want audio input
    pactl load-module module-remap-source master=$sharednull.monitor source_name=$sharedsource  source_properties="device.description=Shared-Source"

} &> /dev/null

echo 'Finished setting up Shared-Sink and Shared-Source'
echo
echo 'To setup your applications:'
echo '  First, switch the recording application to the Shared-Source'
echo '  And then set the playback application you want to share to Shared-Sink'
echo
echo 'Unfortunately, you might need to restart the recording app if you ever disconnect your mic.'
echo 'Classic Pulseaudio design issue!'

I'm not super familiar with Pulse Audio, and had attempted to do something similar to this for a lot longer than I'm comfortable admitting. Thanks man, this was extremely helpful.