I want to start of by saying that this is mega basic article on acoustics. It's not intended to do anything but get you started. The study of acoustics is mega hardcore calculus type engineering. I'm not talking about audio engineering, I'm talking about the field that smart people go into. I'm not convinced that having a 100% understanding of acoustics is necessary to capture a great song properly. However, it would be wise to read a few books on the subject. I highly recommend Alton Everest's Master Handbook of Acoustics. It's like a textbook, but your recordings will improve!

For this article, I'm going to avoid advanced acoustic theory and instead I'm going to focus on how acoustics effect an actual recording session. While it's preferred to have an acoustic space designed by some famous acoustical engineer, most home recording enthusiasts don't have the $2,000,000 to do it right. I'm going to avoid studio construction as much as possible and get into using room acoustics to your advantage in a real session.

Quit Buying Gear....Get Your Acoustics Together

There are a handful of concepts that extremely important to a recording. As I have mentioned before, the song is most important followed by the player and their instrument. After that, acoustics are most important. Without a doubt, acoustics play a larger part of a recording than high end preamps or compressors, but for whatever reason most of us are sucked into buying the fancy gear first. . Remember, that recording is all about getting the source right. This means the stuff that happens before the microphone is 90-99% of the audio. The other 1-10% comes from selecting the right microphone, preamp, and how we mic. Acoustics play a bigger role than you realize.

How Acoustics Effect A Session

All rooms have reflections. This is fairly easy to hear in a large tile bathroom. If you walk around your home clapping your hands, you can hear the sound of each room change dramatically. What you may not have noticed by clapping (because clapping is mostly upper mid and highs) is there is a lot happening to the low end as you walk around a room.

Picking The Sweet Spot In Your Room

I recommend you grab a tom from a drum set. Hit it and walk around any room. Don't listen for the reverb necessarily. Listen to the tone of the drum itself. IT WILL CHANGE DRAMATICALLY! If you walk around the room hitting the tom, you'll notice that there are places in the room where the tom sounds fuller and has more low end. There will be places the tom seams to have more attack. There will be places where it sounds just wrong and there will be probably just one place where the tom sounds just right with nice attack and a nice full bottom end.

How Big Of Deal Is Finding The Sweet Spot

It can really depend. I think that's just as good of question is ?How important is the sound of your recordings??. It's totally possible that you are putting drum sets, guitar amps, acoustic guitars, and vocals in the worst spot in the room. Now vocals are typically not a real big deal in this situation because vocals don't contain a big low end and other acoustical problems with vocals are solved fairly easily. I guarantee that every single person recording at home can improve their recordings by walking around with an instrument and listening. You can hear this same effect with just about any acoustical instrument. I like using an acoustic guitar for this as well. One of the most obvious examples of the room effecting a recording came from an electric guitar. I was using a 4x12 Marshall with a Hughes and Kettner Triamp. I had the amp in one room. The low end was shaking the house apart. The guitar was thick and huge. Then I put the cabinet in a different room with the same settings on the amp, the same mic, and very very close to the same position. The low end was gone!!!

Nothing changed but the room, but it sounded like someone has just rolled off everything under 200Hz. Amazing!!! What if I had been recording acoustic guitars for years in that same spot? More than likely, my recordings could have been 1,000x better if I would have taken the time to find the sweet spot of the room.

Treatment After Finding The Sweetspot

I must admit that my rooms are not nearly as great as I would have liked. My plans for building a tremendous recording studio have been put on hold for a number of reasons and it looks like I have to deal with my current situation. Luckily I have found a few work arounds to some of my acoustic troubles. Sometimes, I find the place where an acoustic guitar, for example, sounds the fullest, also has some sort of weird reflection going on. No problem at all! I just whip out my Roxul (usually known as Rockwool) sheets that I had wrapped in fabric. These sheets are 2'x4'x4?. I can surround a musician very easily with them and without any trouble at all, block out unwanted reflections. It's very strange, but if I were to take the acoustic guitar and all the Rockwool sheets and move them exactly 3 feet in any direction, the sound of the guitar would change. Don't ask me why, but it's true. It has to do with the way the sound waves in the guitar interact with the walls. Anyway, the point is that finding the sweet spot and adding a little treatment is great preferred to avoiding the sweet spot altogether.

How Acoustics Effect Mixing

Besides tracking the instrument, acoustics really reek havoc in the mixing process. How? Easy, your room is distorting the sound coming out of your studio monitors. It doesn't matter how much you paid for your monitors. If you didn't spend $20,000 on treating your control room, it is probably highly in accurate. Don't believe me? Here's a little test. Play one of your favorite major label recordings. Now walk around the room paying particular attention to the low end. That's right listen to the kick drum and bass as you walk behind the speakers and in front of them. You will hear the low end completley disappear in some places, but in others you will hear the low end at thunderous levels. Why? Well, it's your room playing with the sound coming out of your speakers.

We've all done mixes that we thought sounded great on our studio monitors but when we took them out to our cars, we were highly disappointed. A large part of this is caused by poor acoustics in mixing. Just like with an instrument, the best solution is to put your studio monitors in the sweet spot of your room. This is harder to test with speakers simply because you have to be listening to them from 4 feet away while they are playing.

Michael Wagener told us that he had a 10dB dip at 100Hz in the mix position. Ouch! He used bass tubes along his back wall and he said that this cleared it up. So the possibility for improving your mixing situation is there if you use the proper absorbers. You have to remember though that Wagener's room was already heavily treated acoustically during construction before he even used the tubes.

It Doesn't Matter How Close Your Are

Some people think that they can avoid these terrible acoustical situations by sitting very close to their speakers. It doesn't work that way. The acoustical effect is immediate. Let's go back to my guitar amp situation. Remember, I did my best to put the mic in the exact same place, yet the low end was drastically different. This means that even instruments that are close mic'd are going to be effected by acoustics.

A Few Acoustics Concepts

I've kind of rambled my way through this article. Mostly, I'm just trying to get you aware of a few acoustical problems that we all face. Finding the solution is up to you since every situation is different. However, I'd like to leave you with a few concepts that can be applied everywhere.

*Small rooms generally suck for recording. This is due to the way that low end bounces of the walls. You see sound reflections can actually cause phase cancellation. (Remember the disappearing low end in the guitar amp). This means that reflections at certain frequencies, if the distance of the wall is just right, will actually cancel out portions of the audio. It's like the room is taking an EQ and sucking 18dB at a very narrow notch at 180Hz or whatever frequencsy your room uses.

*Avoid parallel walls. This is a solution that many people can take care of on low budget. Two parallel walls will cause problems. If you can't afford to rebuild with angled walls, there are other alternatives. Book cases filled with various books can be a great start. Stacking your unused guitar cabinets can block it out. Simply tossing up a piece plywood at an angle may fix the problem.

*Avoid using absorption that ignores the low end. All of the tall tales of conventional wisdom always come from your uncle telling you to staple carpet to your walls. Guess what! That's a stupid idea, generally. Do you know why? Because carpet does not absorb low end. Only high end. So if you are going for a boomy, dull sound by all means use carpet. I don't know of anyone who wants that. The same goes for standard pink insulation. The worst of all is mattress foam. Eggcrate foam is not much better, but it servers another purpose. In general, you want an acoustical absorber that will absorb all frequencies equally. The best that I've seen are made of rockwool or rigid fiberglass.