Raspberry Pi OS Buster - Enable USB Sound Card As Default

Raspberry-Pi-OS-Jessie-Enable-USB-Sound-Card-As-Default.md

Raspberry Pi OS Buster - Enable USB Sound Card As Default

Step By Step

1. Disable onboard audio

2. open /etc/modprobe.d/raspi-blacklist.conf

3. add blacklist snd_bcm2835

4. Setup sound device alias

5. open /lib/modprobe.d/aliases.conf

6. comment out line options snd-usb-audio index=-2

That line overrides the /etc/modprobe.d/ files

# These are the standard aliases and dependencies.
# This file does not need to be modified.

# prevent unusual drivers from appearing as the first sound device ###########
options snd-pcsp index=-2
#options snd-usb-audio index=-2
options cx88_alsa index=-2
options snd-atiixp-modem index=-2
options snd-intel8x0m index=-2
options snd-via82xx-modem index=-2

# work around other kernel issues ############################################
# The EHCI driver should be loaded before the ones for low speed controllers
# or some devices may be confused when they are disconnected and reconnected.
softdep uhci-hcd pre: ehci-hcd
softdep ohci-hcd pre: ehci-hcd

1. Play audio without root

$ sudo adduser <your-name> audio

1. Reboot

$ sudo reboot

1. Test it out

$ aplay /usr/share/sounds/alsa/Front_Center.wav

Troubleshooting

BEWARE of .asoundrc which is a hidden file in your home folder - remove it!!