I think all these terms are used when describing the sound stage of your system. Music is subjective to the listener, and the type music they listen to. I prefer a more laid back sound, which to me is the opposite of forward. The word forward is considered fatiging to me, meaning I cant listen for long periods of time. I would decribe Transparency as how well your speakers presents the music, and if it appears to be coming form the speakers, or someplace between the two, where when you look at your right or left speaker you cant really tell music is coming from them. Dark is the opposite of an open soundstage, meaning you can tell where every instrument is placed on the stage. all this is subjective, and as I said earlier, this is the way I see it. What the hell do I know?