I have noticed that the stereo on my Z8 sounds very heavy in low and mid-range frequencies. It seem to lack the "highs" and clarity that I would expect. Does anyone else have the same problem? Or, am I not adjusting the settings properly? I have played with the tone adjustments (bass & treble), but can't seem to find an area that sounds really clean. And, have any Z8 owners changed (or modified) their sound systems?