Soundproofing and Acoustic Treatment (Part 2 – Acoustic Treatment)
Part one of this video is all about sound proofing. Stopping sound from getting in and out of your room.
This part, part two, is about acoustic treatment. Making sure that the room that you’re in sounds great, doesn’t mislead you when you’re making mixing choices, and making sure that the room you’re in sounds good for every element that you’re going to record in that space.
When it comes to acoustic treatment, there are really three different types of tools that you can use. One is absorption. Two is diffusion, and that’s actually a diffusor I have right behind my head, we’ll talk about those in a moment, and third are kind of tuned resonators, which maybe you could argue are a type of absorption.
So I will take you on a tour of Joe Lambert Mastering here in just a minute, and you can look at all of the — all three of these devices. So if you had to start somewhere, I would recommend starting with absorbers. Broadband absorbers.
The best ones here are not made out of foam. They’re actually made out of rigid fiberglass. It’s a little bit like fiberglass insulation, right? The pink cotton candy stuff people are used to seeing in their attics or maybe between walls.
It’s kind of that idea, but much more rigid. If you get this stuff thick enough, it can actually do a remarkable job of absorbing problem frequencies in a room.
People often make these in thicknesses anywhere from one inch, all the way up to six inches, and basically, the thicker you go, the more effective it’s going to be at low frequencies.
So if you have flutter echo in your room, like say you clap and then you hear kind of a little bit of echo, a one inch absorber places in the right areas could kind of help clean that up, but what it’s not going to help you with is breaking up standing waves, and this is another huge issue in many rooms.
Bass frequencies being uneven. Maybe you’re in your mixing position, and it feels like there’s no bass, and you start jacking it up, and then you move back a foot, and all of a sudden, there’s oodles of bass. This is very common. We don’t really have the time to get into the science behind it in this particular video, but there are things called room modes and room nodes. Different spots where particular bass frequencies are going to be amplified or attenuated.
The way to break up these standing waves and to even out the bass in your room is with really thick absorbers. I mean, you can go three inches, you can go six inches, basically the thicker you go, the deeper down they’re going to go.
In an article I have about acoustic treatment for the small studio, you’ll find some metrics in there.
Next, you have your resonators, or your panel absorbers. There are a few different types of resonators. Some work almost like a jug. If you blow into a jug and get a musical note, there are resonators that work on that principle to kind of zero in on specific frequencies.
You can also have kind of panel resonators that again, resonate at a specific frequency and kind of are targeted towards particular problem areas.
The benefit to these absorbers is you can target specific frequencies, you don’t have to over absorb frequencies you don’t want to, there are ways to make them have a smaller footprint than say an equivalent sized broadband absorber. You know, for a really sophisticated studio build, they do have their place, but for the average person building their first project studio, their first recording room, or just kind of improving the sound of the room they’re in, they’re often a bit of overkill.
I mean, these are things that if you’re going to get involved with a real designer who’s going to spare no expense and put together a room as great as it can possibly be, they can be an integral part of those designs, but for most folks, I would recommend starting with a few very thick pieces of Owens Corning 703, this rigid fiberglass, just wrapped in burlap on some type of frame.
These really thick ones say six inches. If you can hang them in the corners of the room, you’re going to break up room modes and room nodes really, really well.
The corners behind your speakers would be a great place to start, starting from the ceiling down, maybe two of them in each corner to get pretty much ceiling to pretty close to the floor. If you have a bit more budget left, you might want to hit the back corners of the room, and then after that, you might get a couple or a few two inch or one inch panels and put them strategically to the sides, to the front of the room, maybe above your head to break up flutter echo and the kind of high frequency zinginess that you’ll find in many rooms.
As far as placing where these go, there’s actually some good tricks you can do with mirrors allowing you to figure out exactly where to put these.
I go into more detail on that in my article on acoustic treatment for the small studio. With a mirror, if you have a friend who can help you out, you sit in your mix position, and you ask your friend to put up that mirror on the wall. Any position on the wall where you can see the speakers reflected, that is a natural place to put an absorber.
If light is able to bounce from the speakers to that point on the wall to your eye, you better believe that sound can bounce from that speaker to that point on the wall, to your ear.
Another common rule of thumb that’s often given is find a place on the side walls that is half way between your speakers and you, and that’s often a very good place to put an absorber.
The same kind of strategy goes for putting them on the ceilings, but very, very effective strategy for placing things kind of on the fly. If you’re kind of doing this DIY.
Now there’s a ton of great DIY resources out there if you want to build your own and I have a whole list of them in acoustic treatment for the small studio article on SonicScoop.com, but there’s also plenty of places that make pre-made ones of very good quality.
Some companies that come to mind here are Real Traps, Ready Traps, GIK Acoustics, ATS Acoustics. There’s a whole bunch of them.
Some of them will make kits where you just buy the Owen Corning 703, buy their frame, put it together yourself, wrap it in burlap, some will do it all pre-made, some will give you custom fabrics and things.
These kinds of acoustic panels can also be really decorative. These companies will often make all sort of kind of speciality, designer fabric, custom fabric, you can often get your own design.
One important thing to thing about is making the covering flame retardant. Fire resistant. Straight up burlap is pretty flammable, and also depending on where you might live or work, there might be fire codes that kind of require that these things be flame retardant and not just straight, untreated burlap.
So just another additional thing to think about. All of these acoustic companies have options that are going to work in that regard.
Really, all you need is rigid fiberglass, Owens Corning makes 703 that’s probably the most commonly used thing, that’s just the brand name of their rigid fiberglass, Owens Corning 703.
If you’re at an inch or two inches, you’re mostly breaking up or absorbing I should say, high frequencies, high mids, kind of mids, and as you add inches, you’re going deeper and deeper.
If you can get really thick ones and mount them in your corner, they can make really effective broadband absorbers that kind of work as very effective bass traps as well.
Just two of these panels, say, two feet by four feet, hung up in the corners behind your speakers can have a real impact. Better yet, do four of them. So you have essentially eight feet in length from the ceiling on down.
If you can add another two or four in the back of the room, you’re going to have good results that way as well. From there, you might want to think about adding another four or a half dozen — maybe two or three inch panels to start on the side walls and the ceiling above you. This is going to break up flutter echo and a whole job like that doesn’t have to cost a ton.
I mean, you could spend less than a thousand dollars, and do some — you know, serious work. A couple of thousand dollars, oh my goodness, you’ve got a lot done. Honestly, even just starting with a few hundred bucks and some kind of DIY kits to do this with, you can make some serious improvements to the low end in your room, or breaking up your biggest problem spots when it comes to flutter echo.
Then your third things we barely talked about so far is diffusion. There are some great, great resources for making your own DIY diffusors, there’s also a lot of great off the shelf models.
This diffuser behind me, the idea here is not absorption, but sounds hit this and they scatter in many different directions, and it can kind of make a back wall almost disappear, and make the space feel larger than it really is without there being kind of any echo.
Diffusion I think is huge and very helpful to have in any room. It kind of makes this back wall disappear.
Alright, so there you have it. Your three main components of acoustic treatment. You’ve got your broadband absorbers, you’ve got your tuned resonators, which if you’re doing a real big job and getting some professional help with this, they can be an integral part of a design.
Then there’s the third, your diffusors. Often enough, most rooms you can start and often end with just one straight in the back of the room like we have right here.
Alright, I hope you enjoyed this little demystification of sound proofing and acoustic treatment. This has been Justin from Sonic Scoop, I’m here at Joe Lambert Mastering, and I’m showing today for my boys DeGraw Sound, I just did some masters for them today. They were nice enough to give me this t-shirt a little while back, so I’m rocking it.
Thank you for making awesome and for giving me my DeGraw Sound t-shirt. Keep the mixes coming. These guys do tremendous work. If you don’t know these guys, they have a studio near me in Brooklyn, and just tremendous, tremendous sounding records coming out of that studio.
But anyways, this has been Justin from Sonic Scoop, coming at you once again from Joe Lambert Mastering, thanks for spending some time with me on the Sonic Scoop blog, and hope to see you again some time soon. Alright, thanks.