It ain't easy to make a sound-treated wall in a dorm room. My ceilings are high, my room echoes when I talk, and I'm not even allowed to make any permanent changes to my walls! But I've figured out the best way to do it - and I couldn't be happier with my results!
How to Make a DIY Acoustically Treated Wall (even in a dorm)
Step 1: Gather materials. On Amazon for about 20 bucks, you can order 12 panels of 1'x1' pieces of acoustic foam. I got the kind with straight line groves (because it was the cheapest and like I've said...I'm a college student) but any kind will work. Now, if you're working in a room that you own and you can significantly alter, buy some spray adhesive, make your life easy, and just permanently stick the foam to the wall! If you are working with a rented space, you're going to need to find a hot glue gun, some poster board, and sticky tack or masking tape!
Step 2: Hot glue. So.... the foam WILL NOT stick to the walls unless spray adhesive is used. I tried tirelessly to use everything and anything non-permanent. The foam is just too porous. However...you can use the permanent stuff on the foam, and just glue it to poster board, and the poster board will attach to the walls using nonpermanent methods! So you can hot glue (or spray glue) the foam to squares of poster board. I suggest cutting the squares of poster board slightly smaller than the foam panels.
Step 3: Get it ready for the wall. Now that you've attached all the panels to poster board, you can hang the poster board side to your wall using any method you prefer! I did some with sticky tack, and some with masking tape, and had success with both.
Step 4: Arrange accordingly. To get the best results with my straight groove foam, I did every other board horizontal and vertical. Not only does it look awesome, but it will be the most effective arrangement for blocking out noise!
I hope this helped all my fellow college student DIY musicians!