When you do a aplay or arecord with a lowercase -l you will get a list of devices
when you do the same with a uppcase -L you get a list of available PCMs
pi@raspberrypi:~ $ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: IQaudIOCODEC [IQaudIOCODEC], device 0: IQaudIO CODEC HiFi v1.2 da7213-hifi-0 [IQaudIO CODEC HiFi v1.2 da7213-hifi-0]
Subdevice #0: subdevice #0
All linux commands -h / --help give you basic paramters.
Often there is the Pi built in audio that for many just confuses and with a hat just turn of by editing /boot/config.txt and put a hash infront so that it becomes a remark
# Enable audio (loads snd_bcm2835)
You can press f6 to select or just pass the card index alsamixer -c1 or whatever
Have a look at Ideal Settings for reSpeaker 2-mic hat
Just copy and paste and see how you go.
To further confuse even if a device is shared its settings and conf files are totally separate when in a docker container as docker containers are isolated as thats the point.
You need to docker exec -it <container_name> /bin/bash and check and set inside the container
Also don’t use hw:0 indexes use plughw:0 indexes as that enables software autoconversion so any sampling rate or format error will just get converted rather than fail
Don’t use the desktop version of Raspberry as the addition of pulseaudio as default further confuses.