alsa audio passthrough service with fifo

aplay.service

[Unit]
Description=aplay passthrough audio from arecord
BindsTo=arecord.service

[Service]
Environment=INPUT=/var/run/arecord
ExecStart=/usr/bin/aplay $INPUT

arecord.service

[Unit]
Description=arecord for USB audio device
After=sound.target

[Service]
Environment=OUTPUT=/var/run/arecord
ExecStartPre=mkfifo $OUTPUT
ExecStart=/usr/bin/arecord --disable-softvol --nonblock --device=plughw:CARD=CODEC,DEV=0 --format=s32_le --rate=192000 --channels=2 $OUTPUT
ExecStopPost=-rm $OUTPUT