Hi there i have the same speakers but am not as impressed with the volume.
Wonder if you could post some levels like master soundcard volume and mixer volumes, be a great help to me :)
my master is at about 70% and each individual mixer level at 50% and for music playback (through direct analogue and through coax digital ) i can stand the external decoder volume on full, although that is extremely loud. DTS movies are quite a bit louder through the coax, but im concerned there might be a fau;lt with the amplifier.
I emailed logitech and their support staff sugested that if the same low levels through analogue were there from other sources then the speakers might need returning. But that was before i had the chance to test music through the coax, which is the same sort of volume.
Any sugestions would be much appreciated.