It would probably be OK, but probably not as effective as the normal mounting, although with tile/vinyl/hardwood floors and drywall ceilings it probably would be fine. I think the reasoning behind the normal layout is that lower frequencies are less likely to be absorbed by the ceiling and floor so they can point at the floor and ceiling while the tweeters are generally pointing at walls or listeners.

This is all speculation though...


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8