Hi I was wondering what is out there for material that can be placed under a rug to increase sound absorption and maybe do a bit of soundproofing, I know that soundproofing from a rug is impossible but hoping it would just improve reduction of sound traveling to the apartments above and below my own.

It takes mass to increase isolation. You could place lead sheets under a rug to increase isolation, assuming it covered 100% of the floor. As for absorbtion, you could place some sort of foam or felt backer pad, but typically a floor is better left reflective, no rugs or carpets, with some exceptions...

Do you know where I could find the lead sheets?

Lol, it was mostly a joke, but a closed x-ray facility might have some you could get cheap. My point was it takes mass. Think brick walls, concrete, etc. Heavy, thick things decoupled with airtight cavities. To do this on a floor above ground level is expensive. How much isolation do you need and at what frequencies?

Lead is poisonous. You dont want that laid on your floor under a carpet.. plus the mass you will need will collapse the floor and you'll fall into the appartment below!

I'm sure you could make small improvements to isolation still and could be enoug, depending on what you are doing.

Ya, i guess isolation is too ambitious! it does not have to be perfect, just wondering what I could add underneath a rug to improve absorption, that isnt rock wool or knauf fabric.

Hello,

Could you define your problems (vibrations, speakers, subwoofer, Spl... ) ?

I'm using Focal Shape 65's, no subwoofer in an 17x15 ft room 10 ft. ceiling.

This is only part of what dinococcus is asking. This certainly gives more information. I would venture to guess that he wants to know more about what sort of problems are your speakers and/or sub causing. Is the floor vibrating too much, at what levels are you listening to in order to cause this problem. Are your neighbors complaining? Have you played music through your system and gone to the unit below or above to see what they hear (bass frequencies, high frequencies)?

I think this will help anyone trying to advise you as to how to best move forward.

I'm no acoustic designer so please take this with a grain of salt and do inquire with others who know much more than myself, but my guess to come up with something that might have some impact on the neighbor below would be to put a layer of shock absorption material on the entire floor all the way to the edges of the room, then a layer of 1/2" plywood, then 1/4-3/8" engineer snap on wood floors with padding underneath. And of course hold the floor short of the side walls and add some acoustic caulk around the edges. I'm sure the shock absorbing material could be some sort of rubber, but I recently came across 1" rebonded foam with 6lb/cubic foot density that may do the trick.

The problem with my suggestion is that it's not a true and tried method, so you run the risk of wasting your money. But my thought is that it would certainly help.

For the neighbors above, I'd do resilient clips with hat channels and 2 layers of 1/2" drywall with either a mass loaded vinyl sheet in between the drywall or a sheet of sound board (or homosote) whatever it is call in your area. Again, the drywall should be held from the side walls and either acoustic caulk or some of that rebonded foam could be applied to seal the edges. (this is probably more conventional method that has been used)

Both of those take up a lot of time and money. You can always go get the heaviest rug you can get and maybe some rug padding underneath, but as Jason said, the floor is most times better left reflective.

As always, if anything I've posted above is incorrect, please feel free to correct me.