I’d like to spend a little time talking about a topic that we have yet to touch on in this blog, and it is in regards to the effect that your room (ie. your home studio) has on your mixes. What I hear far too often is the notion that acoustic room treatment is too expensive and that there’s no way I can afford it when I’m saving up for all of this sweet gear.
FALSE! The most expensive gear in the world cannot make up for a bad sounding room.
What if I told you, that you could do loads to improve the sound of your room for cheaper than the cost of the next plug-in or rack that your planning to buy? Now that I have you attention, allow me to reiterate that treating your room should be the first thing on your to do list. (Assuming you already have the essentials to make music) Let’s see what easy DIY things we can do without breaking the bank.
Before we start, it is important to understand what I mean by respecting your room. When we mix, the goal is to have a final product that will sound its best in all situations, on great Hi-Fi systems, club PAs, and ear buds alike. Your room is going to impart its characteristics on what you hear when you mix. So if your room is bass heavy, then your mixes will come out with too little low end because it sounded good in your room. Continuing along with this in mind, we want to ‘flatten’ or minimize the effect our room has on our listening environment so we can make objective decisions in the mixing process, allowing your mix to ‘translate’ to other systems. Now, you won’t ever be able to have a perfect room, but you can have a better room with just a little bit of cash and some ingenuity.
There are two main issues with any room. One is called the Flutter Echo. This is the boing-y high pitched resonant sound you hear when you clap your hands between 2 parallel walls of a small room (Try it in your shower). The second is low frequency standing waves that cause peaks and nulls in the low frequency range in your room. These can cause parts of your room to sound really bass heavy, and other parts of your room to have no bass at all due to cancellation.
There are two methods of room treatment that we use to combat these issues: Absorption and Diffusion. For most of you, absorption will help with the majority of your problems, and it comes in two flavors as well: Mid/High Frequency and Low Frequency absorption. I’ll get into how to treat for each.
Most of us, if your lucky enough to have your own music room, are probably in a small square or rectangular room. So the first thing you want to do, if your in a rectangular room, is orient your desk so that you’re facing the shorter of the two walls. You ideally want everything to be symmetrical so get out the tape measure and find the center point of the wall. You can mark it on the base board with some gaff tape.
Also, if there is room, try and leave about 8-10 inches of space between the back of your desk and the wall, more importantly, between your monitors and the wall. Having your monitors right up against the wall, especially if they’re rear ported, will cause a build up of bass frequencies.
Now that you’ve got your desk and monitors in place, it’s time to take care of those early reflections. When sound occurs in a room, what you perceive first is the direct sound traveling from the source to your ears, followed by echoes of that sound bouncing off the walls in all directions and again arriving at your ears at different times. This is reverberation and the early reflections are the first sounds taking the most direct path bouncing off the walls back to your ears. Here are some diagrams showing early reflection paths.
Both of these diagrams assume a greater distance between the listening position and the monitors (like if you had a console between you and the speakers). But I’m betting that most of you will be closer to your monitors than that so it’s more likely that the sound from your left monitor is bouncing off your right wall and then headed back to your right ear. In either case, this is bad. These early reflections are the next strongest signal compared to the direct signal and they are going to interact with the direct sound and muddy up your stereo image. This essentially means that you will be less able to discern between fine changes in panning while mixing.
Early reflections are a good case for mid/high frequency absorption. This is what the Auralex foam is for, but we can make some of our own absorption panels for cheaper. Any kind of foam or carpet will be better than a bare wall, but if you can spend a little money on some fiberglass, this will be ideal. Owens Corning makes rigid fiberglass in two varieties 703 (less dense) and 705 (more dense). Both come in FRK (foil backing on one side) or regular (no foil). They also come in different thicknesses. For absorption panels, we don’t need the FRK. You can get a 4′ x 10′ sheet of Owens Corning 703 1″ thick for around $30-40. (Or any other rigid fiberglass duct board) This sheet will allow you to make five 2′ by 4′ panels. If you can afford 2″ thick, it has a better absorption coefficient in the mid/high frequency range.
You’ll need to look up your local HVAC Supply center as most home improvement big box stores won’t cary this in stock. Ask around to see if you know an HVAC mechanic. Maybe they can get you distributor pricing.
Now that you have your materials, you need to locate where to place them. A good trick is to have a friend hold a small mirror on the wall while you sit in your mix position. Anywhere that you can see your monitor in the mirror, is where you should put a panel. In a smaller set up, you may be able to get away with just two of the 2′ x 4′ panels, one on either side. That leaves three other panels for other areas. For those, I would suggest placing one on the ceiling above your desk, centered between you and your monitors. The other two can be positioned on your front wall.
If your room is like mine, I had two windows occupying prime room treatment real estate. But you can vary easily go to the hardware store and get one sheet of 3/8″ plywood to cover your windows (1 sheet covers both of my windows). You may be thinking, why on earth would I do that, I don’t want to live in a cave? True, humans weren’t designed to live in caves, but I can always go outside if I need some fresh air. Not to mention that it adds a bit of comfort knowing that people can’t see inside my studio. It also helps to keep the sound in somewhat (I’m also a drummer). I simply measured the plywood so it rested on the window sill and was about 1.5″s larger than the window space on each side. This way I could screw the plywood directly into the wall and not have to worry about framing it to fit inside the window. You can even leave the blinds down between the window and the plywood so none of your neighbors think you are a weirdo.
Now I’ve seen some people go all out and cover every inch of their room in absorption material. While this may be ok for a rehearsal type practice space, it is not advisable for a mixing room (with the exception of very small rooms. Very small rooms with low ceilings will need more absorption). If you make your room too dry, then you may mix with too much reverb as I stated in the beginning of the article. In fact, once you’ve cover the main early reflections, you may be alright. Remember, too, that any furniture or bookshelves you have are also going to help break up flutter echoes.
A Few More Things
So far we’ve covered the material that you need to make your absorption panels, but you still need to get them on the wall and you might want them to look nice. If you’ve ever handled fiberglass before, than you know it is itchy and generally sucks, so you’re going to want to cover it with something. You can usually get burlap at a local fabric store for pretty cheap and it usually comes in a few different colors (I went with black). If your feeling extra thrifty, you can try looking to see if you have any local coffee roasters. They will usually give you their excess burlap coffee sacks which they usually throw away (maybe they’ll even have a cool latin american coffee related print on them). And if that doesn’t work, thrift stores will often have a fabric section where you can usually find some old curtains or bed sheets or something that will work fine. Make sure to not get anything too tightly woven though, you want the fabric to be acoustically transparent.
You’ll also need some lumber to make frames with. You can get 1″ x 2″ striping at ay hardware store for about $2 a piece in 8′ pieces. Here are some other sources showing how to construct and mount the panels:
In the next article, I’ll discuss an easy design for low frequency absorption, better known as bass traps.
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