floor problem

i tried build the floor as in the tutorial......timber floated...........i used 2" rock wool mounted with plywood 3/4"..single layered yet for cr . side walls and ceilings yet to be done. when i hammer the floor to check the sound .....it sound boomy and tailed...is it for another layer of ply yet to be putted? or it already should have been dead enough?

Regarding floating floors: viewtopic.php?f=2&t=8173 http://www.nrc-cnrc.gc.ca/obj/irc/doc/p ... /ir802.pdf

It is a big drum head Md.poneer. I do not know what you have built this floor on, but if you had a concrete floor, you would have been better off to use that. As we know it, mass is what it takes to stop sound vibrations so when you think about this floor does it have mass? Not much...and even if you add more it will still be a drum head but the natural frequency will move down. 3/4 plywood has about the same weight as fire rated 5/8 sheetrock, so you might get an stc rated for a one side sheathed only wood framed wall/floor of about 25 stc. If you added (doubled the mass) another sheet you might gain 3dB, now you are at 28...double again (two more sheets to the already existing 2 sheets after the first doubling) and you gain...3 dB. Lot of stuff to get 31 which is a bit better than an average interior wood framed assembly with 1/2 rock on both sides. But there is still flanking. The wood wall frames sitting directly on top of the plywood essentially tie all of the walls and floor together so that any vibration that runs thru one will go directly into the other, and reduce the overall TL of the build.

@xspace: the floor was concrete.....i used rubber pads then stud frames 2'x2' cell (very heavy as made of gurjan wood)....then 2" rock wool floated faced with the 3/4" plywood as the tutorials showed....... what can i do now........?

What I would do, is take it out! You do not need it, it does not work, and it is a waste of time and money. You already have a good concrete floor there: that is excellent for a studio. Take out the useless "floating" floor, because it is NOT floating. Read the information that I gave you about why you do not need a floating floor, and also about how to float a floor CORRECTLY. I gave you that so you can understand the problems with trying to float a floor, and the very, very high cost of doing it correctly. So that would be my advice: take it all out, and just use the concrete floor, which is very good for acoustics.

Hugh! What a waste........anyway what is gone is gone. Now our local people use sands full of stud cells to make the Floor non reflexive dead sound.... Since, my floor is not all leveled same There are ups and downs as there was toe let which I broke For larger space.besid pulling out all the studs is another time killing And expensive,.....can I put sands in those cells And then put plywood on that?

Now our local people use sands full of stud cells to make the Floor non reflexive dead sound....

You would only need that if you did not have a massive floor already: you do. Yours is concrete! Sand is not necessary. Why do you think you need to float your floor? How much isolation do you need? You ONLY need to float your floor if there is a good reason to do so, such as if you need very, very high levels of isolation. So first you need to define how many decibels of isolation you need, and if you have other issues that might imply floating.

can I put sands in those cells And then put plywood on that?

You can, but that would add even more expense, and for no benefit! Floating a floor also means that you have less height in the room, and height is important for good acoustics.

So after pulling off the studs , I have to Put a concrete plaster as the floor is not evenly Flat .....then what? Should I fix plywood directly on the floor To reduce reflecsivness or put 3 mm rubber before that.... Or just put wooden finish Materials directly ......

If the floor is not level, then use self-leveling cement to fix that. Once it is level, then one good option is to install laminate flooring. It is not expensive, it is y to install, it looks very good, and is also good acoustically. (Sometimes it is called "floating floor", but that is not really a good name, as it does not "float" in the acoustic sense, so don't get confused about that!) It looks like this: http://www.laminate-flooring-installed. ... tures.html

Inshaa Allah , i need to record at night ,may be drums too .....

How much isolation do you need? such as if you need very, very high levels of isolation. So first you need to define how many decibels of isolation you need

im not that sure about dbS.........im at the basement .need to isolate the sound to prevents the sound to transmit to the upper floors or neibours ......... by the way there are 5 feet gap from the building to the boundary wall . do u think the floor with laminating is sufficient?