CW, yes, I think the problem of having multiple tweeters at different points on the horizontal axis can be problematic and lead to time smear distortions and complicated reflective patterns. I think that's why vertical arrays are generally more successful and coherent. Plus in panel and ribbon speakers the drivers do not have much vertical dispersion...
You can get more relative bass with horizontal stacking, but sometimes too much bass and then the imaging usually becomes more vague, as well.
You can get more relative bass with horizontal stacking, but sometimes too much bass and then the imaging usually becomes more vague, as well.