If we learn proper breathing habits, practice intelligently and pay attention to decent body use, our sound gravitates to a resonant whole without this dark and bright crap. It is possible to influence sound through hardware, but the resonant "ring" of good sound is NOT A FUNCTION OF HORN OR MOUTHPIECE! If our sound does not have projection, then our problem is not bright or dark. It is a dull or mushy sound that is not fixed by listening to the masters, rather by learning to play properly.
If we like our sound, but it has no projection, then we have a bigger job ahead of us. We need to fix body, breathing and ears.