Reverting back to 10.4? (Because 10.5 audio quality is AWFUL)

I've been utterly disappointed with 10.5.

Not only am I having installation issue on the Windows side... now I'm having issues on my Mac.

Long story short... Tried to install 10.5 on my Windows machine so my mom can get iOS5 on her phone. For the past few days, it will NOT work. I've followed various threads on the Windows iTunes board, A LOT of people are having the same issue.

Anyway, now I'm trying to update my Macbook and it updated. However, the sound quality is awful. It seems like the speakers blew out or something (I know it didn't because the same MP3s sound fine on quicktime and VLC.

How can I revert back to 10.4 (without time machine backup)?

Thanks!!