Thanks for that. I actually solved it another way, which surprised me. I un-installed Amarok and re-installed Amarok2 for KDE4, and the sound issues seemed to sort themselves out (which wasn't what I was trying to do, but was an unexpected bonus).
I have no idea why this worked - even the startup and shutdown sounds in KDE were deafening which, to my knowledge, has nothing to do with Amarok. Perhaps a KDE bug? As I mentioned before, the sound was even very loud in Kaffeine which was fixed after the Amarok update. Very strange.
Anyway, thanks for the reply
