It depends on what you mean by bright and what is causing it.
If your speaker is a cheap speaker with poor-quality tweeters, there is not much to be done about the harsh quality of the treble.
On the other hand, some amplifier/speaker combinations have excessive output in the treble due to the speaker having a high impedance in the treble frequency range. Audessy and other compensation programs can adjust the speaker output in that f range to compensate somewhat.
Originally Posted by lite2
Read some where that if a speaker sounded bright that Audyssey xt could get rid of the brightness. Is this true? If so, would it also change other sonic qualities of the speaker?