Mojo - My usual listening position is 17 feet away from the center channel. I am watching a movie now in which the dialogue is measuring between 54 and 66 dB, and it's crystal clear.

What you are describing is highly unlikely in a properly operating VP150 unless your room is really doing a number on the speaker. Keep in mind the crossover is 2700 Hz. Run a 2700 Hz sinewave in your system, and it is a very high pitch.

Even if the tweeters were disconnected, it should not sound like a "heavy drape" is over the speaker.

You should consider sending your speaker to Axiom for testing.