This will show you how to do the same with old coffee cups.
Here's what you need, Coffee Cups A LOT of them about 16 per foot of wall.
But these are easily found where ever hot beverages are served. (or the garbage can next to that place). Or ask the owner if you can set up a box for recycling them.
Coffee cups are mostly made from polystyrene and in my opinion is a horrible compound and should be eliminated all together.
The only way to do this is to recycle it until the point that it is no longer possible to produce profit from it.
And a adhesive, you can use just about any kind, spray glue, hot glue, wallpaper adhesive but i find that great stuff spray in foam insulation works the best for this project. You'll need about 8 -10 for a whole room or basement.
Step 1: Step One: Remove Wall or Add a Second One
But works well in empty wall spaces, or as i did for a friend a layer of foam cups and carpet covered plywood did a amazing job, he can now use his basement to practice with his very heavy metal band with out disturbing his neighbors.
Also filled ceiling in basement with cups the sound was reduced at least in half from the basement to the first floor.
P.S Your wall space may be thinner then the height of the cups , so you can just cut them down.
Step 2: Step Two: Gluing the Cups to the Wall
Now the way you glue them to the wall is important! But very easy you just glue them to the wall
one bottom first the next top first then bottom ect ect see picture.
now do this for the whole wall. It goes a lot faster if you lay a line of great stuff then stick the cups on.
The key is to get them as close together as you can.
Step 3: Step Three: Replace Wall or Add to Interior Wall
If your gluing the cups to a board, take the board and mount it to the wall you would like sound proofed cups against the wall. For extra sound proofing add a layer of carpet on the other side of the board.
To attached it to the wall i just used some more wood and and wall anchors to secure it, as so not to crush the cups or fall from wall.
There you go Sound proofing with recycled foam cups, Now get out there and build that recording studio in your basement you've always wanted.