Just an FYI, timidity works great for everything here, but if you want dosbox to be able to use it make sure you add your user account the the audio group otherwise you might get dmix errors.
I thought I had this problem fixed it worked the first time, now I am back to getting errors with dosbox. I have my dosbox.conf setup correctly but when I run any game I get this error.
ALSA lib pcm_dmix.c:1008
snd_pcm_dmix_open) unable to open slave
Can't open pcm device 'default'.
Couldn't open ALSA pcm device (`s')
I've searched around for a fix but I can't seem to find anything.