Tuesday, June 5, 2012

Analyzing Your Room

There is just a ton of software on the market to help you get a handle on your room sound. It ranges from a free RTA you can get on your cell phone all the way up to analytical software costing hundreds or even thousands of dollars. I stumbled upon a trick that costs way less than that and it can really open your eyes (ears) up to what's going on in your room.

It started back around Christmas time when I had a recording rig set up to take thirty some tracks of the live performance for a DVD. In a rare moment of down time I decided to take a couple impulses to use with my convolution reverb plugin later. For those not familiar the setup is this. You activate the reverberant field of a room with a loud noise. This can be a starter's pistol, rim shot, blast of pink noise or just about anything you want. You can create crazy effects with it but for traditional reverb sounds you want a big, quick blast of multitambral sound.

I handed two chunks of two by four to the intern and headed for the mix. We had a pretty sensitive mic on hand, I forget what it was exactly (Gordon?) but it was good enough that it picked up my mouse clicks from eighty feet away. BANG! and we had a reverb tail. Months later I found it sitting on a hard drive and put it to work. I chopped out the initial sound and left just the tail of the sound bouncing around the room.  Now whenever I want something to sound like it's in my room, I turn on the convo plugin, open that file and off I go.

Boy was I surprised by what I heard. I took a clean vocal and ran it through my room sound. It was hideous! I had started out with the sound too wet and it was a triple dose of everything that's wrong with my room. I could plainly hear, in stunning detail all the horrors going on between 300 and 500 Hz. I wound up going with a different impulse for that project, a cathedral in Germany I think, there's tons of them on the internet. 

But it got me to thinking. Most of the software you can get will look at how your speakers interact with the room. This is pretty complex stuff and sometimes simpler is better. Hearing how a loud, point source sound activates the room let me zero in on exactly what was up with my room. Taking a look at the original impulse file with an RTA or spectrograph enabled let me see how much of the problems I hear every week are the result of a couple dozen speakers interacting with each other, and how much is due purely to the room.

You can do it too, all it takes is a reasonably good mic and a DAW. A short burst of pink noise from the sound system will give you the reaction of the system in the room, and a loud bang from an instrument or tool will give you more room information.  The Reaper DAW is what I used. It's an open source platform that comes with some pretty decent plugins. There's a small license fee but it's free to use, there's just a wait screen if you don't pay up. By using the ReVerb plugin along with a spectroscope plugin I got a pretty up close and personal view of my space. Pretty cool for no money and a few minutes of screwing around.

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