I have the logitechs myself, and I think they are great for my studio and rehearsal work. I do not like the sound of my voice through this system. It is very harsh and boomy. I'm using a Shure Beta-57 through the Tyros. I think I sound Yukky, like i'm in a closet or something.

When I go through the Powered Mixer and the 15"'s, my voice sounds rich and sparkly with good mid-tones.

I have taken the Logitechs out to rehearsals with a singer, and with the BASS all the way down, the system sounds boomy and lackluster.

Let me quality the above by saying, this is to MY taste and you mileage may vary.