Comment 6 for bug 622663

1. You should set your Java to Sun JRE (OpenJDK's audio support is too limited). This can be set globally using these instructions, or locally, by setting the following line in ~/.zekr/zekrrc-debian:
ZEKR_JAVA_HOME=/usr/lib/jvm/java-6-sun

If you do step one, you won't see any problem like:
java.lang.IllegalArgumentException: Master Gain not supported

2. After switching to Sun JRE, hanging problems or master gain problems will resolve. But as Java audio tries to get exclusive access to sound adapter, no other application can use sound adapter when Zekr is open. Otherwise you will see exceptions like this:
net.sf.zekr.engine.audio.PlayerException: javazoom.jlgui.basicplayer.BasicPlayerException: Cannot init line
...
Caused by: javax.sound.sampled.LineUnavailableException: Audio Device Unavailable

In order to workaround above issue, you should force Zekr (and Java) to use OSS interface (Open Sound System) and this can be achieved by wrapping Zekr with padsp. So open a console and write the following command to launch Zekr:
$ padsp zekr

This should resolve any sound-related issue for Zekr.
Please let me know if you still have problems with audio on Linux.

Mohsen