Decouple Framing or Walls? - Page 2

Ted, I think I may have misunderstood you here! The framing is indeed spaced out from the foundation walls about an inch or so, but the entire framing has been encased in 4" of 2lb, closed-cell spray foam. I know that the consensus here is that spray foam does little/nothing for sound proofing, but there is much less sound transmission through the framing and up to the joists. It's not exactly scientific, but banging on the framing with a variety of materials transmits much less sound to the upstairs after the spray foam was installed.

And to what effect on other frequencies? Is there any testing/data out there in this regard? It's quite evident that the sound transmission through the walls was reduced greatly when the foam was put in. I don't want to say there will be noticeable results without actually doing testing, but it appears as such based on simple observation.