Sound proofing floor

I am at the point that I don't need to modify or purchase anything else. But I am considering sound proofing the floor for the sake of my neighbors which know that I will lower the volume when they ask. I am considering raising the floor and making that raised floor decoupled from the room and insulated.
Any ideas?
Adding a 2nd floor should be very effective. Use flexible caulking and then trim to cover the crack between the 2nd floor & the walls. Good luck.
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:

Your walls will also carry vibration to the structure below, so soundproofing could be a pretty big project.
Good luck.
I had that in mind- using the mass loaded vinyl on the floor.
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.
If you have a layout of your equipment and furniture that you will be using it would be a big help in determining placement of minimal support for your added floor.
Don't forget to use T&G ply & glue the joints with something like PL400.
Instead of mass loaded vinyl try to find the heaviest cheapest vinyl flooring on sale(sized to fit room as one piece) and pick up the heaviest "used" foam u/l from a flooring contractor(it normally just goes in the garbage).
Glue the foam to the floor and lay the vinyl over it-gluing the vinyl only to the walls all around to prevent leakage. Relaxed vinyl is vastly more effective.
A layer of vinyl directly on the floor beneath the u/l would be an excellent economical improvement as well.
I will be very interested to follow your endeavour.(I would not recommend lifting your original floor, not worth it, but highly recommend you eliminate any squeaks before you start-and if I were doing it I would rescrew the original floor as a first step using 1&3/4 inch deck screws. Rattles would be very annoying. If the result is not quite adaquate the next step would be to work on the ceiling below. Cheers. Pete
Thank you!
One other concern of mines(I know, it never ends) is the outgassing from the foam. I am not a health nut, actually a quite balanced health oriented individual. The outgassing is an important concern though, and in the winter when the stack effect forces air and vapors to move upwards it'll just end up saturating my living space. So I am hesitant with not just the foam but most materials that are being considered. I think the vinyl will not present as big an issue as foam would. The outgassing concern is what has kept me from going forward with this project as it has been on my mind for a while. Any suggestions Psacanli?
In addition to what I just posted: Something I was considering was cotton batting to avoid the outgassing issue.
I appreciate your concern Pedrillo & I think it's wise to considerate those eventualities.
I did mention we want the vinyl to be 1 solid piece and also to seal it to the walls(PL 400 will work permanently). I believe the vinyl will slow any outgassing significantly enough that normal routine ventilation will be adaquate. Let's face it most homes are carpeted and the outgassing will move through carpet much easier (faster) than thru vinyl. In addition you will want your plywood floor to be airtight as well-providing a second barrier. So, I think it should be okay. I was not aware of the cotton batting option but I imagine it would be pretty good.
Thank you Psacanli, you know you make a good point the vinyl should do a good job of slowing down the outgassing! I was also concerned about the vinyl itself, I remember in my research of outgassing that foam was one of the greater culprits and that plastics too, the softer the plastic the greater the outgassing. I don't expect the plywood to slow gassing too much but if vinyl proves to be not so harmful then I will go with your suggestion! Thanks!
I am in the middle of a sound proofing project and have found the Green Glue web site to be an excellent practical and no nonsense source of information and test results. I would encourage you to read everything on this site before going too far. They discuss a variety of common approaches and solutions and counter some things that seem intuitively correct. Whether you choose to use their products or not, it is very helpful.
Here is the link.
Green Glue
Green glue appears to be the most commonly used adhesive in soundproofing projects. A friend has a Rives-designed dedicated room which used a lot of that stuff.
As someone has already consult with an Acoustic Engineer (not some builder who has done acoustic work).
Acoustics is a science (unless we try to design a Concert Hall where it becomes more of an art), and what may seem logical to the uninformed can often be disastrous.
Putting in another floor is a pricey exercise and you want to do it ONCE and CORRECTLY.
Most of the advice posted above would spend your money for little result.
Sound travels in 2 basic ways....STRUCTURE BOURNE and AIR-BOURNE.
The trick is....the air-borne can become structure-borne and vice-versa.
Unless you TOTALLY decouple your new floor from the old, the STRUCTURE-BORNE sound will travel through.
Only an Acoustic Engineer can visit your situation and advise on the possible solutions.
I concur entirely with getting consul from an acoustical engineer, I needed to hear that from members, thank you.
Please inform us of the acoustical engineers advice. It will be interesting to look at the cost benefit ratio. Without going into specifics your idea of a 2nd floor islolated from the 1st is 'very' effective and I think you will find this confirmed by the engineer. (My father is an engineer)
Zargon, thanks for the info on the green glue. I'm doing some renovating and soundproofing for a suite and I'll definitely benefit from your input.