I just compared the VP100 to the VP150 and found a 2 to 2.5 dB difference between the two in my living area using the AVIA disc and a Radio Shack SPL meter (the VP150 being the more sensitive). I agree with John and Sushi that you shouldn't find a 5 dB difference between the two centers. But it sounds as if you were calibrating by ear and recognized that the center was noticeably louder than the other speakers. Were you to the side of the sweet spot? I found -- as others have posted -- that the VP150 has greater dispersion. Alan and Ian have said that this is due to the TWWWT driver arrangement (as opposed to the WTW configuration of the VP100). I found the dialog in both centers to be clear, so I did not experience the problem you describe. But I did find the VP150 to be noticeably better for my large room. My wife (who couldn't care less about audio equipment) put it best. While watching the opening scene from Oceans 11 in which the parole board is interviewing George Clooney's character, she remarked that the VP150 made it feel as if she were at the table. I agree. The VP100 is a fine center, but I believe the VP150 delivers a more immersive experience.