This query of mine is more for members owning Onkyo HTiB like Onkyo HT S3500 or HT-S3700. As I understood going thru the specs, the sub-woofer is a down firing one. Isn't that a problem? in a sense that the sub tends to undergo a lot of displacement while in action, it won't stay at the initial place and will gradually shift from there mainly on marble floors? I am speaking this out of my experience of a previously owned Logitech 2.1 speaker system.
I own 2 Onkyo's and both are front firing... but yes a down firing one will dance around the floor... I've seen one do it in the past, but easily controlled with a small carpet.