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RE/P Files: Control Room Acoustics With George Augspurger
From the archives of the late, great Recording Engineer/Producer (RE/P) magazine, a discussion of the problems and several of the solutions involved in renovating an existing control room structure from the March / April 1974 issue.
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R-e/p: Tell us about redoing the control room for Village.

GEORGE AUGSPURGER: From my standpoint, even before getting into the subtleties of those things that the client may like, there are a number of things you do in any control room.

One is that you try to get the thing as nearly as possible to be bilaterally symmetrical. You’re stuck with two channel and four channel stereo, which are both oriented left and right, and to get any kind of control in the center of the room you’ve got to have the left and right identical.

So the first thing to do is to make the left and the right halves of the room identical, at least acoustically, if you can manage that. And in this case, (Village studio B) that was easy. We shoved the center of the console over a foot or fourteen inches, and developed the whole room symmetrically from the mixer’s position.

Then the next thing we try to do is to work with the location of the monitor speakers and the immediate surfaces surrounding the monitor speakers. We try to get a reasonable amount of diffusion in the front part of the room, and try to make use of desirable first order reflections and try to control the undesirable ones.

The desirable ones are the ones that help localize the image where you want it and help direct the sound toward the area of the console, where the people are hearing it.

The undesirable ones are, for example, a reflection off the right wall of the room from the left hand speaker, or something like that cutters up your image. One of the biggest problems is to avoid echoes that ricochet right off the face of the console. This thing is always sitting there, it’s a big reflective surface and it’s always a problem.

R-e/p: Well, specifically what did you do for the Village’s reflections?

GEORGE AUGSPURGER: We used, in this case, two major reflecting surfaces in the ceiling area, above the speakers. We used the side walls immediately adjacent to the speakers. We knew we were going to flush-mount the speakers in the space that was already there, and those immediate surfaces were all worked out, in an attempt to get the proper characteristics.

R-e/p: Did you mean in terms of the angles and the surface material?

GEORGE AUGSPURGER: Right. Those are valuable primarily as reflecting surfaces; there’s not very much absorption on those surfaces. There’s a reflector up there which was suspended so it could be adjusted after it was hung up, in case we wanted to make slight changes. Then, once you get to that stage, you start worrying about the rear speakers.

Admittedly they are not as important as the front ones, but you try to keep their orientation and the overall sound as close as you possibly can to the front speakers. You start worrying about unwanted reflections, primarily off the rear wall, where people like to stack up racks and tape machines and things like that.

Fortunately, in this case we did not have any tall things back there. And you start worrying about the effect of the normal room resonances down in the low frequency region, because once you get into the bass region, as you well know, every moderate to small room just becomes a big resonator with its own characteristics.

What we try to do there is to control the ones that you can predict. You can never predict all of them but you try to control the ones you can predict in relation to the console location. In other words, at this point, you have to give up statistical acoustics. You can’t say, “Well, on the average, there are going to be so many modes in the room,” because the only ones you care about are the ones that are screwing you up right there at the console location.

So we try to break up the major floor-to-ceiling mode which usually is a problem. We use sloping surfaces and traps.


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