Hello Jim,
I can't overemphasize the importance of placement on the sound of a center channel speaker, and how the timbre (tonal balance) of the center will change with often slight differences in location. By the way, you should always set the VP150 or VP100 to "Small" and use an 80-Hz crossover frequency in your setup menu.
When you use pink noise as a test signal, a center will never sound identical to your main left and right speakers. In most cases, the center sits on top of the video display or on a shelf beneath it. The adjacent surfaces--including the TV screen itself--add some coloration that you will hear with pink noise.
The goal is to experiment and find a place for the center where it's timbral balance is the best--where you aren't distracted during movies by any coloration on dialog or music and the blend with the mains is as seamless that your installation will allow. You may have to mount it to the wall with a bracket or try it on a short stand but I assure you, it's possible to get the VP100 or the VP150 sounding excellent.
You can read about my series of tests in the Axiom A/V Learning Center ("Fine-Tuning Center Channel Sound").
What's amazing about how room placement influences center channel tonality is you can take three identical speakers (in my case I used three M22ti's), which sound identical even with pink noise when placed in free space on stands side by side, then move one M22 above the TV, leaving the others on stands to either side, and the M22 on top of the TV will sound different.
Here is an excerpt from the aforementioned article:
"The lesson in all this is that if you detect noticeable tonal differences between your VP100 or VP150 and the main left and right speakers—and you find those differences audible or distracting—then it's time to experiment with placement. Try different locations, even sliding the speaker slightly to the left or right on top of the TV monitor, even if it isn't exactly symmetrical. Some Axiomites have found great success putting the center almost on the floor or on a short stand with the center angled up towards the listening area.
For improved coverage or use with a large screen and a front projector, try two center channel speakers, one above and one below the screen. That way, for most viewers, the two centers running in parallel will image the dialog in the center of the screen, rather than too far above or below the screen. This dual center-channel formation will also reduce the effect of the location on the tonal balance."
Regards,
