I dont consider myself a musician, so, what I dont know would fill a big book. To capo up the neck of a guitar does tend to "brighten" the piece, but, you lose the lows. My favorite chord is D because I can tune the low E down to D and get a really full chord. It's a kick ass chord on a 12 string in the Dminor position. Gordon Bok tunes his down to C and if you listen to Peter Kagan and the wind, you will hear that low note like the crack of doom. It really says a lot at that point in Kagans story.