VERY BAD SOUND: MacBook Pro (unibody) with external JBL Creature speakers

Recently I've bought myself a brand new Mac Book Pro. I'm very happy with my new laptop, but I can't say that about the audio-output quality my new MacBook Pro delivers in combination with my existing external JBL Creature speaker set. In the recent past this speaker set was attached to my old iMac 17" flat, which delivered supreme music quality, but now in combination with my by far more superiour new MacBook Pro, the music sounds very disturbed with a background noise and it seems that the speakers do get to much power/signal - but still the music sounds very far away and the more I pump the volume the worse gets the music output (i.e. more noise is coming out of the speaker) and the right channel seems to have less power (or output). Now I've disconnected my JBL Creature speakers set as from time to time also static ticks are loudly to be heard when just connected whilst I don't do anything with my MacBook Pro.

Can anyone tell me whether this is a problem of the audio-design of the new MacBook Pro (aluminium unibody) and if so is there a solution for to by-pass or overcome this very annoying problem.

Many thanks in advance for your support!