On Sun, Feb 13, 2022 at 09:49:30PM +0100, corbeille wrote: > Hello, > > I would like to know if there is a possibility to create at startup > (maybe in /etc/pulse/default.pa ?) a "connection" between Alsa > input hw:1,0 and a null-sink thru a loopback ? > To have something similar to : > > $ pacmd load-module module-null-sink sink_name=MySink > $ pacmd load-module module-loopback source=hw:1,0 sink=MySink > > Instead of : > > $ pacmd load-module module-null-sink sink_name=MySink > $ pacmd load-module module-loopback source=alsa_input.usb-0d8c_C- > Media_USB_Headphone_Set-00.mono-fallback sink=MySink > > Thus, I will be able to link "MySink" with any sound card on hw:1,0. > > Is it possible ? I don't think it's possible with the normal pulseaudio setup, since the alsa cards are added after everything in default.pa is processed. The module-udev-detect module dynamically loads and unloads alsa cards as they are sensed by the hardware. It's a limitation of the module-loopback code that the requested source/sink must exist at loading time. One thing you could do if your machine only has one sound card on a non-removable connection (i.e. not a USB device) is to statically define it with module-alsa-card and disable module-udev-detect. A more resilient option might be to make a script that checks for the presence of the loopback and loads it if it's not present. Then just fire that script unconditionally before launching your programs that use it. --Sean
