We've received a few customer bug reports about this but I never saw it happen or understood what they meant until now. To reproduce:

Go look at some audio-playing applet. I used http://www.nasoft.com/catband/, but if time is important to you, be sure to use an Animator example.
Now leave the page. Look at Netscape's home or something.
Try to launch an applet with appletviewer or view another sound-playing applet page.
Your sound resource is locked. You have to exit Netscape to free it- the applet does not let go of the sound resources if you leave the page.

Arguably this is mostly a Netscape bug since arguably Netscape provides no way of stopping an applet, or rather they don't completely exit an applet when you leave the page, but I also can't think of a simple way to do this without having to restart the applet when the page is entered. Stopping the thread does not free the resource. I doubt relying on the programmer to release resouces is a very good solution. If this is entirely a Netscape problem, or a common developer problem that they might want to work around, we need to let them know.

10-Apr-96 klc
I see this with both Netscape and the JDK appletviewer, so it's not just
Netscape. I imagine that java opens the /dev/audio device and never
closes it. There needs to be a AudioClip.close() method or something.

I'm bumping the priority to 3 (from 4).