[CentOS] su command

Thu May 8 13:57:32 UTC 2014
Jerry Geis <geisj at pagestation.com>

I am running pulseaudio on centOS 6.5
audio works fine as the user.
running the command
aplay /usr/share/sounds/alsa/Front_Center.wav
works fine.

when I login as root and run the command
su user -c "aplay /usr/share/sounds/alsa/Front_Center.wav"
it does not work.

I thought su actually runs as that user...
is there some "magic" to su I don't know about?
How might I get that to work ?


Thanks,

jerry