Adam Hall Eggbox Foam grey 30 mm

Although foam is known for not being the best material for absorption, this material is an good aid to complemet with other materials, such as acoustic panels. I used mine to create some absorption in some spots of my homemade studio, where panels wouldnt fit. In the end, I turned a very echoey space into a seamingly correct place for audio post-production. Also, I use the remaining foam (since I cut mine into several parts) to use on location, when working as sound operator for film.
In the end, you get what you pay for, so, depending on your porpuses, this might be very handy! Just dont expect it to do the homework for you, i.e. you must study and experiment and acoustics.

I got some of this 30mm foam and also some of the t.akustik HiLo-N25 25mm foam to tame the resonances in my small listening room. They both work but are quite different in the frequencies they reduce. The 25mm is noticeably better at reducing unwanted very high frequencies (the ones that make you wince), whereas this 30mm foam seems to work lower down the frequency range. It may not be entirely due to the thickness because they're clearly different materials - this one feels more rubbery. After playing around for weeks swapping bits in and out I've ended up using a combination of both together (including some double thickness) plus a bunch of rockwool and a dedicated bass trap. In the end it's trial and error to get the treatment just right but it's really worth it. I have a high end Naim system and I've found that the room makes more difference to the sound than the equipment does.