Home Recording - the room

The room where you record has a tremendous potential on your sound. It's easy to prove this. Download the NTI Minirator program and play some tones in your recording room. Try frequencies from 60 or 70 hertz up to about 200 hertz. As you play one, walk around and listen to the volume change drastically, often within a foot or so. These are caused by standing waves and reflections. You have to minimize these reflections; you have to minimize standing waves, or find a location between them. It's possible to find a place to put the microphones that will not be affected by the standing waves, but there are probably other reflections too numerous to avoid. You can calculate roughly which frequencies will cause standing wave problems based on your recording studion dimensions. Here's one way.



My studio is about 30 feet long and 17 feet wide with a cathedral ceiling - and the lowest note of a low tuned 12-string guitar is 61 hertz (I don't tap, so I'm only considering fundamental string notes), so I can probably ignore these first, second, and third node waves of 19, 34, 37, and 56 hertz. The standing waves for 67, 87, 101, 174, and 261 are worrisome, but I can find areas between the nodes to put microphones. I've alleviated some of the problem with corner traps at the end of the room where I've chosed to record.

These are pieces of owens-corning 703 rigid fiberglass, 2 feet by 4 feet by 4 inches covered in muslin and stacked into one of the corners of my studio.

I set up my omni microphones that I think is between the various standing wave nodes and sweep from 50 to 200 hertz, watching the volume indicators on my computer. There seem to be peaks and valleys that are broader than a standing wave. For example, the sweep from about 120 to 170 is much higher that the surrounding frequencies. Hmmm. This could be the response curve of the microphones, which I think is not likely because they are Oktava MC012 and are supposed to be very flat up to about 5K. More likely is the speakers. Nothing I've read indicates that a room could cause broad frequency peaks and valleys. I don't know of any room treatment that will solve this problem, if it is one, so let's wait until we do some recordings to see if it shows up there.

I'm a fan of Ethan Winer's web sites. Most of the ideas here came from him. Here are some other good resources for how to do room treatments:
John Sayer's Forum
Home Recording Studio Design
And here is a source for rigid fiberglass, if you want to make your own traps or soundproofing:
Source for 703