great words dean^...
I always try and equate what I hear to other things in life that help ILLUSTRATE what it is I am trying to convey. therefore, for me, it always takes the form of a visual. when I say the music is more "clear" I might reference looking at a low resolution photograph versus one of much higher Pixel depth... higher resolution or more resolved, eg: LESS noise.
and I wholeheartedly agree that there are two kinds of brightness in music and they are easy to distingush... One kind of brightness makes you want to turn TOWARDS the sound source, to embrace the sound... the other kind of brightness makes you want to TURN AWAY from the sound because it's painful, or annoyingly poor.