it might be the way the sound begins and ends. if it end loud but starts soft, the speaker cone will "pop" during the transition. To fix you could use some sound editing software to ramp up the sound at the very begining, and ramp down at the end. this way the speaker cone will be at the same place during the transition (no popping). I've done this when working on a telophony system a few years back!
Cheers!
If you aim at nothing you'll hit it every time. 806mhz AMD Athlon Processor. 384MB memory.
Windows XP Home Edition. RADEON 9700 Pro graphics card. - editor.exe=1.0.6.1 - DBPCompiler.exe=V1.05