Agreed Jason. I noticed that occasionally as well when comparing the SVS and the 600, but it was indeed subtle. An example is on the opening scene of Toy Story 2 when Buzz light year is flying around corners and igniting his jet pack to accelerate. You hear the jet pack on both subs, but with the SVS I was pretty sure I could hear a slightly deeper rumble on some of the blasts. It was so subtle that I asked myself whether I was making it up in my brain knowing that the SVS went lower, but I'd say it's very probable that it was indeed the lower extension.
On "The Pulse" DVD (sub 20 hz sound), however, the difference was noticeable. Even though there wasn't a lot more audible volume with the SVS, I could feel the walls shaking and the room pressurizing decidedly more than the Axiom. This was nice, and was the trade off I feel one gets by choosing the SVS over the Axiom. However, in exchange you lose a bit of the warm envelopment I heard from the Axiom.
That's a long way of saying I agree with you.
