The mp3 files are stored on the Master Backend at /var/lib/mythtv/music.
This mp3 files is shared by samba at //backend//music/
On the Frontend machine /var/lib/mythtv/music is a mount point for the samba share(requires smbfs be installed).
The Fstab entry looks like:
//backend/music /var/lib/mythtv/music cifs auto,uid=taine,gid=mythtv,credentials=/root/.cifscredentials,file_mode=0775,dir_mode=0775 0 0
This will mount the smb share at boot. The credentials are stored in a file that is readable only by root ofr somewhat better security.
The file /root/cifscredentials looks like:
user=theuser
password=thepassword
Our other issue was to be sure to set the output device under Music Tools Setup to
ALSA:plughw:0,3
We are using the Acer Revo 3610 with HDMI ouput to a Vizio LCD TV.