I've just tried playing the exact same MP3 on my N900 and on my old N73, and the N73 totally whipped the floor with the N900's arse in both sound quality (bass and all) and in loudness (both devices at full volume) ; is there any way i can make my N900 sound as good and loud as the N73 or Nokia shipped the N900 with significantly worse quality audio features even though it's much more recent and much more expensive?

try specifying if you're talking about the built-in speakers or headphones

builtin speakers, i thought that was clear, sorry