Maybe it was just the recording, since it was the 1st time with a MP3 recording? How long have you had the system? Other standard recordings do this too? I agree that the IC's you have should be upgraded (and speaker cables)but I would wait until you get your stands and then play around a little bit. Room acoustics (do you have wood floors, bare walls, etc.), speaker placement, vibration and isolation, etc. I would then look into your cabling as that final icing.
Regards,
Regards,