ALSA warnings

[patrick]

I'm using mpg321 to play MP3 files, and I get a bunch of output if I
run it as a non-privileged user:

ALSA lib confmisc.c:560:(snd_determine_driver) could not open control for card 0
ALSA lib conf.c:3479:(_snd_config_evaluate) function
snd_func_card_driver returned error: Permission denied
ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib conf.c:3479:(_snd_config_evaluate) function snd_func_concat
returned error: Permission denied
ALSA lib confmisc.c:955:(snd_func_refer) error evaluating name
ALSA lib conf.c:3479:(_snd_config_evaluate) function snd_func_refer
returned error: Permission denied
ALSA lib conf.c:3948:(snd_config_expand) Evaluate error: Permission denied
ALSA lib pcm.c:2090:(snd_pcm_open_noupdate) Unknown PCM default
ALSA snd_pcm_open error: Permission denied

On which files/devices do I need to fix the permissions so that these
warnings don't occur?

I would also like to be able to run alsamixer as a non-privileged user.

Thanks,

Patrick