Would center channel benefit audio only room?

There is a range of frequencies within the treble region that tends to be heard as if it is coming from a point that is significantly higher than the actual sound source (assuming the source is directly in front). I believe that range of frequencies may be in the area of around 8 to 10 kHz, although I don't recall the exact range because it has been some time since I last listened to a test record.

So I would suggest that you explore the possibility that your speakers and/or your room acoustics may be de-emphasizing that part of the spectrum. If that part of the spectrum received greater emphasis, as perceived from the listening position, it would probably tend to stretch the image higher.

Regards,
-- Al

Almarg, an electronic crossover and 2 tweeters would allow me to experiment in that frequency range, and the level can be controlled with the crossover.

Tvad, at a normal range; the volume does not alter the soundstage one way or the other.