Your crossover should have a tweeter attenuation circuit with
connections for 0, -3, and -6dB. Try -3 or -6 if you find them
too bright.

In article
(John Matlock) wrote:

I just had a set of MB Quart Discus series components installed in my new
Mazda 6 sedan last week. I have read that Quarts have a reputation for
exceeding brightness in their sound output. That's my problem. The clarity
is outstanding but the overall sound is way too bright even with the treble
completely cut out. just unsatisfying no matter what I do.

Are there any adjustments that can be made to the components to get a more
natural sound? It's driving me nuts! I do have them still running off the
stock head unit's amp, not an external amp. My next thought is to buy an amp
to run the speakers, but would that cut down on the brightness?

any advice would be much appreciated.

JJM