Acoustic Foam Bass Traps -12 Pack Wall Corner Studio Foam Blocks 12" X 7" X 7" Low-Frequency Sound Absorption Material for Home Studio and Theater etc. (12 Pack, Bass traps)

A lot of people are having issues with the product not going back to its original size. The directions in the product pics show to take a blow dryer to it and it will expand and they do. I took it one step further and put several in the clothes dryer on high heat for 10 minutes and they came out perfect!

So I had these (bass traps) before buying panels so I didn't appreciate how these almost immediately rise. The panels needed water, these bass traps didn't. Worth it.

These did the job I needed them for, and were very inexpensive so I'm keeping them in place. They're not very even in the way they expanded from their vacuum packing so they don't look very good, but since they're not super visible I don't mind too much. They do even out bass response without sucking the life out of the room for me, so in that regard I'm happy. (The foam is not very dense so they don't offer much in the way of midrange absorption, but that's not what I wanted them for.)If you want something that's more broadband in absorption and/or looks crisp, look elsewhere. If you want a cheap solution that may help even out bass response and don't care much what they look like, these are a pretty good value.

Looks deform not like the pic

I tried all the methods (wait 24hrs, soak and dry, blow dryer, machine dryer) to get these to expand but I realized its not a problem with expanding, these foam blocks are just made unevenly. The dimensions say 7x7x12, but they all come out to 6.3-6.8x7x12 (each dimension being +/- 0.2 inches) and the problem is that the side that is shorter is not consistent so if you are trying to line these up to look nice, it just wont happen. I found the best way to mount with this problem is to add double sided tape to each corner and stretch out the corners while you're mounting them to line up with the previous block. I won't look perfect but its a lot better if you just pushed each block into the corner and mounted it that way.

Edit: Now that I’m more knowledgeable in the subject of acoustics and acoustic absorption, I found that these “bass traps” attenuate some midrange frequencies, but mostly just a lot of highs. To market these as bass traps is intentionally dishonest. Acoustic foam is most effective at 2000hz and above. If you exclusively use “studio foam” as your acoustic treatment, you will suck all the life and high end energy out of your room, resulting in very unbalanced sound with boomy bass. Don’t make the same mistake I did. Spend a little bit more and build some Rockwool panels. If you DIY it, it’s quite affordable. You won’t regret it.

No matter what I did, the foam wouldn't expand to its original dimensions. It is like the cutting process fused some of the end parts together somehow - perhaps heat. They need to solve that manufacturing issue.

After dealing with some frustratingly non-expanding 12"x12"x2" tiles (a week in the garage, 2 days in the sun, 2 soak/dryer cycles), it was such a joy to open these.24 hours? Haha. Yeah, whatever. More like 24 seconds and fully fluffed! They expanded so fast that it made it difficult getting them all the way out of the plastic.It's the simple things that bring me joy.