Sound proofing floor

The biggest transmission of noise is air leaks, so the suggestion to caulk is a good one.

If you're ready yo go through all the trouble to raise the floor, how about pulling up yout subfloor and filling below it with expanding foam insulation? This should really seal them off from your floor.

John C.

Kind of a two edge problem since the integrity of their ceiling can substantially affect the outcome... Had good luck with a suspended drywall ceiling and the blue jean batting - but that was from the ground floor looking up. The goal was isolate the downstairs guest room from my partners wood floored home office directly above their heads.

Given the probable cost and complexity I am going to offer some obvious advice - call an acoustician or at least a contractor who specializes in home theater or recording studio installations. Get very specific about how many db of attenuation various approaches will actually achieve. And make achieving those specifications part of the contract if you can.

There are some effective ways of decoupling the speakers from the floor - this eliminates a good deal of the vibration that goes through. Checkout some places catering to the semi-pro and pro business like sweetwater dot com and see what they have for acoustic treatments. You could definitely knock the bass down and help matters.

Truth is if you are pounding at 100-110db levels nothing is going to work but building a room within your room.

WHat about that soundproofing vinyl that is meant for walls? You could put that on your floor first before building a new floating floor above it.

Check out the following site for advice:

http://www.soundproofing.org/index.html

Your walls will also carry vibration to the structure below, so soundproofing could be a pretty big project.
Good luck.

Emailist,
I had that in mind- using the mass loaded vinyl on the floor.
Larryi,
I plan on using that vinyl on the walls as well.
My challenge is this: I will build the floor out of plywood and it will be supported at both ends. The span is about 11'(that's the width of the room), so I'll have a joint some where in the middle which will be staggered, and will be forced to use some lumber 2x4 or other. If I stand the 2x4 on edge to keep the floor from springing to low in the middle my floor gets thicker, something I don't want. So I was thinking towards the middle of the span installing srings of a sort? Foam? Rubber? Sorbothane?
But what will it feel like to walk on? And if I am sitting in the middle of the floor and the raised floor sinks to the spring material then it defeats the purpose of the raised floor which is suppose to be decoupled. Any suggestions. How much air do I need between the raised and existing floors to stop the sound from passing through?
In the end I think I will be installing the raised floor joists on edge.