You might be seeing non-working audio output and the following tricky bits in your subsonic log:
Error in jukebox: javax.sound.sampled.LineUnavailableException: Audio Device Unavailable
First thing is to make sure you’re running the Sun JDK and not OpenJDK or something else. Apparently there are things that don’t play well with non-Sun.
If you’ve done this, restarted Tomcat and still have no audio when using Subsonic with Gentoo and Tomcat, remember to add Tomcat to the relevant groups:
groupmems -g pulse -a tomcat
groupmems -g pulse-access -a tomcat
groupmems -g audio -a tomcat
groupmems -g plugdev -a tomcat
To be fair I’m not sure if they’re all necessary, but it works for me. You’ll need to restart Tomcat afterward to make it work.
sudo /etc/init.d/tomcat-6 restart