What anco111 says (maybe some day he will tell us his first name)
makes a lot of sense and I have a recent direct experience with this theory. As quite a few probably know here, I have been a big proponent of stacking the front speakers in pairs of 3 on top of each other to the left and right of the console, preferably if you have the room to get them out in front of you off the front corners of the console, the stacks end up being in the range of 6 or so feet apart to the left and right.
As I've mentioned many times, I've tried countless speaker arrangements, and the stacked speaker arrangement sounds best by far, others here have tried it and from what I've heard have reported the same results. Why do I think it results in sounding the best? Because of exactly what anco111 describes and I've had basically the same idea, just not the good description offered by anco111.
In a stacked arrangement the speakers stay 'in line' with each other vertically and you don't end up with drivers being side by side where the imaginary ripples in the air run into each other and affect each other, perhaps negatively. However, I've had an interesting new revelation concerning a very recent new speaker purchase I made. My previous front L / R speaker arrangement has been one large tower on each side with 2 bookshelf speakers stacked on top. I recently went out and purchased another pair of towers with the plan of eliminating one pair of bookshelf speakers on each side, the new towers would bolster the weakness I felt I had in certain ranges that the bookshelf were not capable of handling properly. Now the dilemma was with the new towers, how to arrange the front speakers? Since I could no longer stack everything on top of each other as things would have ended up ridiculously high, and I don't have the ceiling height anyways, my stacking theory is now somewhat trashed and I was skeptical of the outcome. I first tried placing both towers directly next to each other with the one leftover pair of bookshelf speakers on top. This didn't sound so good as some stops would stand out, some got totally buried in the sound, in any case it didn't sound near as convincing as the previous arrangement. I then tried increasing and decreasing the distance between the front L / R arrangements but kept the towers right next to each other. This didn't help either and I was starting to think I had made a mistake in this new hair brained speaker purchase. Then I figured perhaps the issue is the towers are too close to each other? Sure enough, that was the problem! I ended up spacing the towers about a foot apart from each other (I may try further spacing yet), the bookshelf pair on top of the inner pair of towers, and WOW what a difference! Now it really sounds like I'm sitting right there in the church, the second pair of larger towers has added the mid to the 8' stops I had been missing and the set now has a very pleasing and full sound like it should. Just to be sure I wasn't imagining things I even went to the extent the other night of tearing things apart and went back to the speaker arrangement I have been using for the past couple of years so I could just take a listen and make a comparison. Outcome? Not even a contest. The new arrangement by far sounds better, but the key again is speaker placement.
I can see at some point I will incorporate a single cabinet per side that is of the tower type with speakers arranged vertically in the cabinet from bottom to top, but each cabinet would be divided up into at least 3 channels of separate audio. This would likely sound best.
Go get that Schulze!
Marc