How exactly are you doing your sound effects?
I took some gongs and chimes I had previously made with an FM7 soft synth plus some effects, and exported something like a dozen .wav files of about 3 seconds each. I also have a pad that works as a loop (about 30 seconds). All of these are "resource" files, and played via javax.sound.sampled library code. Some use a WindChime effect (semi-random), some are tied to events--new threads are always spawned to allow overlapping Gongs, so each clip has a chance to decay naturally. Had a LOT of fun with memory leaks and JProfiler with that!
The looper for the pad has a second thread so the beginning can overlap the end (overlap = 125 msec? estimate) and sound seamless. It's kind of a neat acoustic environment, different from most games,
and I hope to have it in the demo area within a couple days as a work-in-progress. ww.hexara.com/game.html
[it takes about 3 minutes to load, due to 15MB of .wavs--less than 2 minutes worth!]
I'm having a bit of a problem with changing volumes on continuous sound, though. Have to use a really small increments. At the moment volume changes at a maximum rate of 0.02 (within allowable range of -80.0 to +6.0) every 20 msec or so, and it doesn't seem to be clicking.
I look forward to checking out other sound libraries, but wanted to learn how to do it with what java itself provides, first (this is a learning project, after all). I'm curious how overlaps & mid-sound volume changes will be handled.