> I am finding my Infinity Reference Kappa 8's to be too boomy <

All speakers will be boomy to some degree in an untreated room. But in your case it sounds like the floor itself may be resonating. Get a friend to help you, and both of you lift one speaker off the floor and see if that helps. If it does you can make or buy isolation pads to decouple the speakers permanently. I've used 2-inch thick 705 rigid fiberglass wrapped in fabric for this, but even an empty cardboard box does a good job.

--Ethan

If you're willing to spend ~$3500.00, you might consider Rives Audio's "PARC" (Parametric Adaptive Room Compensation). http://www.rivesaudio.com/PARC/PARCframe.html

I am compelled to mention corner bass traps, just in case you don't have those.

This next part can be very cheap and effective, but it sounds a little crazy.

It's a DIY thing, but even me, Mr. Ten Left Thumbs has done it:

Go into to crawl space and find the floor joists near your speakers.

Measure the distance from ground to joist and head over to Home Depot for some 4X4's and some concrete supports that will fit that space.

Install them, and then use wood shims to really tighten the interface between the support and the joist.

Measure one half the distance from the support to the back wall and support the floor joists there, too.

I've even seen people do this with a basement below the floor with 7 foot tall supports!

It can be a miracle for your sound!

If you feel really brave, I've heard of people who used "permanent" jacks to support the floor, but it is something you could over do and hurt the floor.

Anyway, the floor thing is crazy easy and well worth your efforts.

Best wishes, keep us "posted!"