class D amp (specifically SI T-Amp) with a powered sub woofer

[cowbaka]

I just ordered a Sonic Impact T-Amp, and I have a Harman Kardon HKTS 14 set of speakers, which include a powered sub woofer. Per the specs, the have an 86 db sensitivity (so they should be OK) although they say input is 10w - 100w, so the T-Amp would be a bit on the low side.

My question is - is it better to hook the T-Amp's speaker-out to the high-level inputs on the sub, and hook the satellites to the sub or is it better to hook the T-Amp only to the satellites, and connect the sub with line-level inputs?

If it's better to use line-level on the sub, what is the easiest (cheapest) way to take my line level input and connect it both to the sub and the T-Amp? Will simple RCA Y-Cables work or would that reduce the signal sent to the T-Amp too much or possibly distort it?

I suppose I'd need some sort of pre-amp if I wanted to connect the sub with line level, or else my volume controls would be in 2 separate places (the sub has it's own volume control, but it's designed to work with signals that are volume controlled on a receiver / preamp). Do you know of any small, inexpensive devices that would fit the bill?

Hopefully this makes sense. I'm a bit electronically literate, so a minor DIY project to rig something up to accomplish what I'm looking for (if Y cables aren't ideal) would be fine.

Thanks!

[Pano]

Don't use the speaker level inputs, your Sonic won't like it.

You got the rest right, you'll need to drive the sub line level and you'll need some kind of preamp to send the signal both places. The preamp will also give you a unified volume control.