I would have to say that the statement of 'wasting time switching cables' is a little off the mark, as cables can greatly impact the overall sound. (Van den Hul vs. Kimber, in general, have totally contrasting characteristics - Van den Hul being warmer/slower vs. Kimber being lively and quick). Having said that, I believe a combination of what was stated in the previous responses can help to finely tune / tone down the 'brightness'. Try placing a large area rug on the floor in front of your speakers. Also, putting some form of sound absorption material on the wall behind this system will greatly help, whether it be a wall-hanging decorative rug or sound absorption material specifically designed for that purpose. Side walls (first reflection point) and wall behind the listening area should be similarly tamed. Some or all of these changes can help to tame the beast and won't break the bank in doing so.
To much high
This weekend I traded my B&W CDM1's for a pair of beautifully finished home-made speakers, comprising a Morel tweeter, Seas (aluminium) mid/low and Seas woofer in a tall housing. I listened to them on a tube amp in a heavily furnished room, and they sounded awesome. Back home (you guessed it....) I connected them to my transistor amp, in a rather hard-sounding room. The low and mid is everything I ever dreamed of, but the top-end is driving me nuts. Since I don't have the cash to change my amp I'm thinking of changing my (silver) speaker cable, or, as some sort of last resort, placing a resistor before the tweeter. Any (other) suggestions?