On the other hand, there have been several people here that have used a center channel same as their left and right speakers without any problems. That's an ideal situation. Some modify cabinet dimensions to fit nicely as a dialog speaker and used drivers that didn't have such long magnetic reach. Sometimes, the cabinet is made short and wide or vice versa, keeping the driver position relationships the same or close to it. Provided that is done and cabinet volume and tuning are right, it usually works pretty well.

The main thing is to maintain a uniform horizontal pattern that is reasonably wide, not to use a speaker with side by side drivers. Nothing kills sound quality worse than that, because nulls form smack dab in the middle of the listening area. It is also important that the center channel match the left and right channels in tonal character and volume, so that side to side panning sounds natural. One of the hardest things to do is to position the speakers so the sound comes from the same place as the images, not too far above or below the screen. It's usually best to put the center speaker directly above or below the screen, and the left and right channels just to each side and at about the same height as the center speaker. It can be tough setting everything up that way, and sometimes you have to make tradeoffs.