"Setting the center channel to "large" is better sounding regardless of how small your center speaker is because when you set your receiver/processor to "small", the receiver inserts a high-pass filter, usually steep-slope and not of the greatest quality, to remove the deep bass and protect your center channel."
Dave, thanks for the response and info. I surmise that what you describe is happening with my Sony DA4ES receiver that I am using as processor.
I noticed something else I don't like when using the center speaker, whether set to large OR small. And that is a loss of ambience details, compare to setting the receiver center channel setting to "none". I was switching back and forth, and when I am set to "none" and the sound is just from the front L/R, there is a lot more sense of space and background ambient noises in the mix(example, traffic and city sounds).
It seems like a good processor would retain that spacial information even through a center channel speaker, or would still direct it to the front L/R. Are there any processors that pull this off very well?
I am starting to get an itch for a processor, but the Sony has so dang many features I like, it will be hard to find a processor that has them, phono input and TWO multi-channel inputs(I have HDDVD and a Universal player) just to name a couple.