Originally Posted by dumdum12
But I still don't understand theory behind the statement "MTM on the side will not sound good".
It's because the dispersion pattern of a toppled MTM is just horrid. What you end up with is wide-open vertical
dispersion (ignoring upper-midrange issues in speakers with flush-mounted tweeters), which will lead to massive amounts of floor and ceiling bounce that will, among other things, smear dialogue like no tomorrow. In the horizontal axis, a toppled MTM will have severe problems as well, leading to a very narrow coverage area.
For some data to go along with those assertions, see this article.
Or, without the words, look at the measurements of the mains and center channel of this Dynaudio speaker set.
Note how wretched the off-axis response of the center channel looks in the midrange. All
toppled MTM's do that. (A "2.5-way" will be marginally better, but not excessively so. In general, stay away from any
speaker system that includes what looks like two woofers with a tweeter in the middle. Two woofers flanking a vertical mid-tweet array may be worth listening to, though. Ditto two woofers flanking a coaxial mid-tweet array, a good coax being my preference for all channels.)
To be perfectly honest, the only reason the toppled MTM center even exists is that most people (even those who spend as much as they would for a good bespoke suit on their audio gear) are either deaf or have such pitifully low expectations that awful sounds OK to them.