View source for Pulseaudio SPDIF Input, LFE remix

== Route the SPDIF input of the Aureon 5.1 USB Soundcard to its 5.1 output ==

=== For my ESP32 Bluetooth to Toslink Project, start this ===

 arecord -f S16_LE -c 2 -r 48000 -D iec958  --disable-channels --disable-format --disable-softvol --disable-resample -B 100000 -t raw | \
 aplay   -f S16_LE -c 2 -r 44100 -D default --disable-channels --disable-format --disable-softvol --disable-resample -B 100000 -t raw

Bit strange: BT A2DP sends 44100 samples/s but iec958 seems to be locked to 48000, so fix speed during output or voices are a bit too high

=== For a good sound, the LFE needs to do some work for the small satelites ===

/etc/pulse/daemon.conf

 enable-lfe-remixing = yes
 lfe-crossover-freq = 100

To enable changes

 systemctl --user restart pulseaudio.service


== Loopback line in to line out ==

=== PulseAudio Control ===

This has long delay

==== Start Loopback ====

* pactl load-module module-loopback

==== Stop loopback ====

* pactl unload-module module-loopback

=== PulseAudio Cat ===

This can have short delay

Install pulseaudio manager to look for the audio device names, then write script to start the monitoring with short delay

* sudo zypper in paman
* paman -> look at property of sink and source (to copy/paste the long names)
* write script to start monitoring
  pacat -r --latency-msec=1 -d 'alsa_input.usb-FMIC_Fender_Mustang_Micro_396234823131-00.iec958-stereo' | \
  pacat -p --latency-msec=1 -d 'alsa_output.usb-0ccd_USB_Audio-00.analog-surround-51'


== Loop Job4 Audio to Fender Mustang Micro ==

To feed chordsplay.py songs running on job4 into Fender Mustang Micro as backing track via bluetooth

script is in /home/joachim/pa/job42fender.sh

 # send linux sound to fender amp to play along 
 # use wired headphones on the fender amp to avoid delay
 # or wireless: 
 #  mustang-micro->3.5-male-male-cable->3.5-female-to-6.5-male-adapter->iRig2(through)->Cuvave-TX-> ~ ->Cuvave-Rx->Amp
 
 fender_mac='84:17:15:15:F0:20'
 fender_sink="bluez_sink.${fender_mac//:/_}.a2dp_sink"
 fender_source="alsa_output.usb-0ccd_USB_Audio-00.analog-surround-51.monitor"
 
 echo -e "power on\nquit" | bluetoothctl
 while ! echo -e "show\nquit" | bluetoothctl | grep 'Powered: yes'; do 
 	echo "Wait for power on"
 	sleep 1
 done
 
 echo -e "connect $fender_mac\nquit" | bluetoothctl
 try=0
 while ! pactl list sinks short | fgrep "$fender_sink"; do 
 	echo "Wait for $fender_sink" 
 	try=$((try+1)) 
 	if [ $try -gt 5 ]; then 
 		echo -e "connect $fender_mac\nquit" | bluetoothctl
 		echo "Restart device?" 
 	fi 
 	sleep 1; 
 done
 
 echo "Connect $fender_source to $fender_sink. Ctrl-C to end"
 pacat -r --latency-msec=1 -d "$fender_source" | \
 pacat -p --latency-msec=1 -d "$fender_sink"