Using xmame (SDL) version 0.106 (Apr 20 2009), cannot get sound to work properly. When looking at the command line options that gmameui passes to xmame (sdl), there are several options that cannot be removed: -volume 0 -bufsize 3.00 -audiodevice -mixerdevice -dsp-plugin -sound-mixer-plugin -samplefreq 44100. When I enter the same gmameui command from the command line w/o these sound related options, the sound works.
I am using Ubuntu Lucid 10.04 with gmameui 0.2.11 and xmame (SDL) 0.106, and Pulse Audio (libsdl1.2debian-pulseaudio), all from the Ubuntu repository. Perhaps this is an issue where the pulse audio does not like those command line options?