Basics of Room Treatment and Acoustic Panels
Hey folks – I realize its been a while since we’ve had an opportunity to talk but things have been busy over here. For one, I’ve moved. I didn’t move very far, but most of the work isn’t in the distance of moving anyways. Of course throughout this move I’ve been without a studio or any means to really get any work done but times are changing and you could very well say that I’m back in the game
As I was planning out Studio Laminar v4, I was in a particularly interesting situation – I had no garage and a much smaller house… no where to put things. What you don’t know is that in Studio Laminar v3 I had a large number of acoustic panels, but they weren’t hanging, they were leaning against the walls or sitting around in the garage. The severe lack of space meant that I had every single panel sitting in this smaller room – it was high time I dealt with these things and figured out how to hang them up. Not too mention improve my mixes.
But wait a second – you are probably asking yourself why I didn’t have them hung up in the last studio. Well… we tried. I wasn’t sure how to do things and employed a friend to help me. We actually devised a really cool system to mount the panels and move them around easily as necessary. We created beams and intended to mount them around the room from which panels could hang. There were a number of benefits to this plan however with the first hole we drilled in the wall… water started pouring out. Turns out we hit a high pressure sprinkler pipe made out of pvc that was in a closet separator wall. Yea.. flooded the house and begged the landlords forgiveness. Let’s just say after that I lost the heart to really take anything on in that particular residence.
Well, I’ve made it and into a new house, now time to hang these things up. When it comes to acoustic treatment there is a, how do you say, metric fuck-ton of shit to learn. There are also some fundamental concepts that come into play. How you choose to address these concepts is more or less up to you. Although I’m going to point out a bunch of stuff here, you really need to do your own research and come up with a solution that fits your studio. Note also there’s a huge point I want to make ahead of time.
Work with what you have. There’s no way its going to be perfect but it can be better.
Alright, there, I said it. With that, let’s talk a little bit about ‘basics’ – note, you can get all kinds of great explanations on the web, I just hope to guide you to things to read more about but there’s no way I can cover everything here and do it justice.
What’s it all for?
Our primary goal when treating a room is to take the room out of our sonic equation. Your room, all rooms, have a sound and that sound is going to mess with our ability to make quality mix decisions. This sound is called reverberation, but there are other things going on. You’ve got room modes happening, standing waves, and probably some others I can’t think of right now. In a perfect world we’d design an awesome room and life would be.. perfect – but our world sucks so instead of acoustically treat the room in efforts to make it somewhat live-able until we’re able to build our dream studio.
What’s all that stuff mean? The two things I find the most difficult in an untreated room, in order of awfulness:
- Bass (remember those room modes I mentioned? go read about em)
- The room’s sound (reverberation)
- Standing waves (read about these too, slacker)
How do we deal with all of this? We place things around the room that eat up sound (except in the standing-wave case but i’m not really talking about that in this article). I’m definitely not getting into panel construction here, but most people find the best bang for their buck is to use Owens-Corning 703/705 (or similar brand) rigid fiberglass. Various insulation materials have different sound absorption characteristics, this stuff just works particularly well for what we do. There are all kinds of ways you can build this stuff into panels, but most folks use hollow frames and wrap them in fabric.
All kinds of things can be done depending on how you want to use the panels, how effective you want to be, and how much time you want to invest. Want to know more? A couple of google searches will blow your mind – keep in mind the home theater guys are pretty good with this stuff too.
Does one type panel solve all problems? Nope, but they work good for high frequency absorption. Remember that note I made about bass earlier? Well that’s a little trickier to solve. These sound waves are much larger and have a lot more energy. As a result they are a lot harder to reduce. For this reason we usually talk about bass traps as a separate entity even though they are more or less the same thing as the acoustic panels we’ve been talking about. Bass traps come in few forms running from something similar to the panel I’ve described above to these things called “super-chunks“.
You might remember briefly above when I mentioned using a hollow frame for the panel. There’s actually a really good reason for this. Whenever sound hits a surface its going to bounce back. While a sound continues to travel, it usually loses energy (it takes energy to move, duh). Therefore if you give your sound more room to travel, it will lose energy and you can eat up more of it with your panel. Now consider a backless panel. Sound travels to the panel, some of the sound is absorbed while some sound passes though the panel. The sound loses energy between the panel and the wall. The sound hits your wall and reflects, traveling through the panel a second time, being absorbed a second time.
I’ll stop for a second, read that twice and come back here. Done? Good. Basically, by placing space behind your panel you provide room for that wave to lose energy. This is how you get thinner panels to do a better job on low frequencies in the room. This is also, in fact, how you can get a lot more out of your bass traps. Want to know more? Check the related reading below.
There are a million ways to go about treating a room but first you need to at least know why you want to do it and some of the things that come along with room treatment. Along with this comes all sorts of cool science as well as a couple other topics for later blogs: Diffusors and the great question “where the hell do you put these things and how the hell do you have them up?”. I’ll leave you now with some reference material to peruse should you be interested. Expect those next couple of articles pretty soon, I miss you guys and i’m a little pent up.