OK to use Splitter for 2 Subs-Receiver has 1 port

Onkyo might know a tad bit more about their products than folks on an audio forum. Just a thought.

Yes. However, you should (1) place them equidistant from the listening position and (2) adjust them for equal output before you do your full setup because you have only 1 setting for subwoofer distance/level in your 905. Stacking them might be effective.

Kal

I'd not be inclined to used 2 different subs - basically the sound mismatch. As for the onkyo, you could use the sub out for one, and a pre-out for the other. Of course it would make setting up a mess.

I'm surprised Onkyo had an issue, you are just outputting a raw signal. Lots of people use 2 subs. But, heh, it's their product, they should know best.

I'll second what Kal said.

Dave