Hi! I’m building a multi-room setup using a Raspberry Pi 4 as the server and multiple raspberry Pi Zero Ws as clients. All of the Pis will be using external USB DACs. The living room (where the Pi 4 Server will be) also has a turntable, so I was wondering if there was any way to incorporate it as a source into the setup? The turntable has a built in preamp, so could I theoretically get something like the Behringer UCA222, connect the turntable to its RCA inputs, use that as the USB DAC for the Pi 4 server, and then broadcast the turntable to the other Pis in the system?
There is an experimental mode to use soundcard input, as described here using the environment variable SOUND_ENABLE_SOUNDCARD_INPUT. We’ve actually built an audio block to speed implementation of audio capabilities that might be of help. You can learn more here https://github.com/balenablocks/audio/.
Thanks, John! I’ll mess around with it once I’ve got the rest of the setup stable. Does the soundcard input just be transmit constantly, or does it need to be triggered somehow when you want to play from that source?
I haven’t tried this myself, but I assume the audio input source is constant – as long as that audio service (container) is running. Of course, there are probably ways to programmatically set the source (say, through device variables). This would add another level of complexity, but it’s quite workable and there are lots of examples of device variables being used this way. Sometimes, those setting will be applied when a shell script grabs an environmental variable value and performs an action based on that.