The acoustic treatment world does not do themselves a lot of favors. On one end of the spectrum you have cheap, and for the most part worthless, foam panels in all kinds of shapes and sizes that are somewhat inexpensive and actually look that way! And the other end are acoustic panels that actually work but cost hundreds if not thousands to install.
ACOUSTIC FOAM
If you enter a room completely covered in acoustic foam or something like it, you can tell pretty quickly it is doing something with the sound. So when I posit foam is worthless, I am not claiming it does not work for some frequencies. But that’s also not the point.
If you shop around for acoustic foam, there are a million companies selling it. And nearly none of them provide any type of testing data to support their claim their junk actually works.
There is a sound absorption coefficient that is usually applied to acoustic testing so that you can compare one product over another. When I look at the coefficient for RockWool, it is easy to find their rating. But when buying acoustic foam, you mostly just need to trust the manufacturer’s claims. Ahem, no.
Even when you can find test results, it is pretty obvious acoustic foam is not without its limitations. 1” foam will hardly dent your room, especially below 2-4k. And forget about low-mids and lows. 1” foam just doesn’t work. At all!
I have seen test results from 4” foam, and it does create more absorption in the mid-lows. And yes, the thicker the foam the more absorption you achieve across the entire spectrum, but now we are talking about 4” foam! A quick search on Amazon and I found one brand for $5 per square foot, but you had to buy it in bulk for $230. And even with 4” foam you don’t see much absorption at 250hz and below.
If you reference the coefficients for foam bass traps, of course they are better at all frequencies, especially low-mids and lows. They are usually 2-5x thicker than wall traps. But again, we are now talking about foam that is 6-10” thick, and usually not that wide. I typically see corner foam traps in 12”x17” varieties. They are 17” wide and cover 12” of wall on either side. So even if the corner foam is absorbing all frequencies, it is not wide enough to cover a corner effectively.
Since corners are typically very deep when it comes to sound trapping, you need a deep corner trap to capture the waves that persist there. The traps in my studio are 16” deep, 32” wide, and have 23” sides. And since corners are a great place to fill-up a room, the deeper the better!
With a little geometry, you can identify how deep and wide traps are actually covering. A foam corner trap with 12” walls will have a width 17”. The width is the part facing the room. If you divide the width in half, in this case 8.5”, that is how deep the actual trap is away from the corner. So a typical corner trap is only 8.5” deep.
And usually foam corner traps are not solid, they tend to have ribs on them that are supposed to act as diffusers. OK. I want absorption, not diffusion. This just lowers the absorption coefficient.
So in reality, a foam corner trap is barely 4-6” of actual, solid foam! Mine are 3-4x deeper. And given it is hardly “deep” to begin with, and it will cost you about $100 per corner at 8’ in height, I can hardly see a reason to choose foam other than it looks cool to some people. To me it looks cheap.
Installing foam is also quite a fun process. And it is not without a lot of fuss. Gluing it to a wall just ruins your wall. Using stick pins may be the best option, but even then the foam isn’t really secure. Someone rubs against it and like Velcro it will rip from the wall. And let’s not forget how awesome it looks if installed out of square! Now that’s professional!
And finally let’s talk about maintenance. Foam is a huge dust and junk collector. Anything that floats in the air like animal hair or dander, dust, whatever, will stick to it. Sounds like a real healthy way to treat your expensive room right? And whatever you do, don’t damage your foam! Now it looks really cheap!
ACOUSTIC PANELS
But that’s not the end of my bemoaning about acoustic treatment. Now we have actual acoustic panels on the other end of the argument that can actually be tuned to an environment, ahem, they work, and don’t come with all of the cheap pitfalls of acoustic foam.
I am not going to get into a comparison between foam and acoustic panels. It’s not even an argument to me. But the one area where foam has acoustic panels beat is price! Especially if you buy your panels and have them shipped to your studio.
Foam is easy to ship. They simply suck all of the air out of the wrapper and stick the lifeless blob into a box. Less than a few pounds even for an entire room!
Acoustic panels on the other hand are bulky and heavy. Most of them made with insulation that is not light, and framed in wood which is also quite heavy. Shipping even one 2’x4’ panel likely costs 4x more than an entire wall of foam.
And then there is the cost of the panel itself. I have seen 1” panels go for $150 which is a joke. Like foam, a 1” acoustic panel does literally nothing. How about a 3” panel? They are like twice as much! Or a bass trap? Literally like $250-1000 depending on the height and depth.
For most home studios, the cost of true acoustic panels is way out of their price range. Which is why so many of us choose to build them ourselves.
In my 100sqft control room, I have 25% of my vertical corners covered in traps (~$500 retail), 80% of my ceiling (~$1,000 retail), and 25% of my walls (~$1,500 retail) covered. And the room is pretty damn flat! And I made all of the panels for less than $1,000! That’s a $2,000 saving over retail panels!
If you want to just buy traps and not make them yourself, I recommend ATS. They sell on Amazon, and the shipping is usually about 25% of the overall cost.
The ATS corner trap is 24” wide and 13” deep, and goes for $170 + $45 shipping. My traps cost around $100 each, and they are deeper.
Their 4” wall panels (2’x4’) go for around $90 with $23 shipping. My mid traps cost around $50 each, and they are 6” deep.
And their 2” panels (2’x4’) go for $70 with $17 shipping. My high traps cost around $35, and they are 3” deep.
CONCLUSION
As you can tell, there is no way you can convince me acoustic foam is a good alternative to acoustic panels. There are just too many cons and not enough pros. And likewise, you won’t catch me buying acoustic panels retail from Sweetwater or anywhere else. The price is outrageous and the cost to effectively treat a room is just too much for my pocketbook.
If you would like more information regarding making your own acoustic panels, check-out a couple chapters I wrote on the subject:
2.) The Crowe Traps
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