It turns out my problem stemmed from the ini setting the CF too high. Everything works perfect now apart from Mario Kart which has been crackling from the start. To Azimer - take as long as you want making your new plugin, if it betters your already excellent existing one, I'll be a very happy guy.
Good... I hope I can fix some of the crackling in the future... 90% of the crackling in games that do run at 57+ FPS is my fault. The other 10% is DirectSound/Emulation fault. On games that run < 57+ FPS (like 45 or less and not talking about PAL) is 10% my fault and 90% the fault of DirectSound/Emulation. Mario Kart's intro shouldn't crackle. Try this... disable Speed Limitation. You will find it reduces the crackling in those 57+ FPS roms tremendously! This is due to the fact that the audio varies from 57FPS - 62FPS when it's waiting for the next audio stream.