Installs The Acoustics of Building an FOX Mix Position

[DavidDaMonkey]

The FOH position for the theater I work at is right behind the last row of seats. I'm somewhat crammed in with various folding tables as my "desk." We are getting a new board which is even deeper than our current one, and I think I've finally got the boss's ear about getting me some more space. The wall behind me basically covers up about a 4-5 foot deep hollow concrete space with 3 or 4 concrete supports that are holding up the actual booth above. That booth is where the follow spots and the light board are, as well as a stage manager's booth. This booth is about 15 feet above the floor level where I am currently at.

I would like the wall behind me knocked out and then that empty space treated and built up to give me an actual desk and a mixing area with some rackmounts, etc. I know this is alot, but the boss seems interested in what I have to say.

My question is how will this affect what I hear. I feel like if enough space is cleared, it wont make a huge difference once the walls are treated. My only worry is low end audio getting trapped in there, but again, with a big enough space, I don't see this being a problem. If it was a problem, I guess we could put up some bass traps.

Anyone have any thoughts on this? I will try to take some pictures when I'm up there tonight.

 

[DaveySimps]

It is difficult to say exactly how it will effect the sound, as every space is drastically different. There are just too many factors to take into account. As a whole. I think it is a great idea to have the project done, as long as you are not altering the supports for the booth overhead. Just as in most other situations, you will have to adapt your hearing. After the renovation is complete make sure your schedule includes some extra rehearal or sound check time for your first few shows. Use this time to walk the space so you can hear things from the audiences prospective. Compare this to what you are hearing back in your mix position and make note of the differences. Over time you will begin to notice the differences every show has in common. For example, you may notice that you are consistantly hearing more low end than most of the audience and may have to accept that at mix position knowing that is not what your audience is expirencing. This will help you mix accordingly.

~Dave

 

[DavidDaMonkey]

Yeah, hearing more low end was the main thing that I thought would happen. Am I correct that all things being equal, the larger the "hole" that I am in, the lower the frequency of the bass that I "overhear" will be?

 

[museav]

The further you get from being in the same environment as the audience, the more you have to consider that fact. For example, if you move back, will you still be in the direct coverage of the speaker system?

You mentioned that there are several concrete columns with what appears to be infill between them. What is the infill and is there other access to the area behind it? One option might be to turn that unused space into an equipment room with racks that mount through the wall and provides a lockable service access, and perhaps storage area, behind the wall.

Of course, there could be code and other implications with any modifications, such as if the space is occupied it may have to be ADA accessible and sprinklered (is that a word?).

 

[DavidDaMonkey]

There isn't even infill in it. The only thing in there now is the snake that's running from the amps up in the booth down to the board.

Also, I would still be in the direct coverage. My worry is the reflections that would happen in the space.

 

[derekleffew]

An old trick I've seen many times is to take the console's road case cover and put it against the wall, foam out, behind the engineer. Having a hard, reflective surface close behind you can really wreak havoc on one's mix.

In an ideal world, all mix positions would be dead center of the audience, and take up only one seat. That happens approximately...never! So, make the best of what you have and realize that everything is a compromise and must be compensated for accordingly. It could be much worse: many sound consoles are located in a booth behind a sealed glass window. :gasp:

A major theater here in Las Vegas recently moved the FOH from center of the audience to behind the last row, under an overhang. The only reason I can think of is to gain back those 20-30 prime seats.

 

[DavidDaMonkey]

Yeah, the stage manager's booth upstairs was originally the audio booth, with a glassed in window. I refuse to operate from up there unless they make me (such as the the annual elderly tap dance show we do where my usual spot is taken up by wheelchair seating...no joke). One of the guys that used to work there took out the plexiglass window and put it in the dumpster, or hid it somewhere. No one has complained.

 

[museav]

There isn't even infill in it. The only thing in there now is the snake that's running from the amps up in the booth down to the board.

You mentioned it being a wall with 3 or 4 concrete supports, which I assumed are columns. Infill would be the 'wall' construction between the columns and/or beams, usually concrete block or stud construction. If that is non-bearing stud wall construction, then cutting openings into it or removing it may be fairly simple. If it is concrete block or is a bearing wall, then removing or modifying it could be more complicated and expensive.

Another consideration, do you have power and cabling access where you would need it or what might be involved in addressing those.

Also, I would still be in the direct coverage. My worry is the reflections that would happen in the space.

Like Derek noted, you can treat the walls to limit reflections, but does that potentially make your situation even more different than that of the audience? While I understand the purpose of adding acoustical treatment behind a mix position at the rear of a room, I always find it somewhat incongruous to address it as a problem for the mix position but to then not address the audience in the same situation. If you do add some acoustical treatment, think of where it should be, if the speakers are up higher then anything hitting the rear wall at your ears or below is going to reflect down below to where you don't really hear it. There may only be a small band of height that actually directly affects what you hear.

I actually think that on center is not usually an ideal mix location, a bit off center or even midway between the center and side is typically more representative of what the majority of the audience hears.

 

[DavidDaMonkey]

You mentioned it being a wall with 3 or 4 concrete supports, which I assumed are columns. Infill would be the 'wall' construction between the columns and/or beams, usually concrete block or stud construction. If that is non-bearing stud wall construction, then cutting openings into it or removing it may be fairly simple. If it is concrete block or is a bearing wall, then removing or modifying it could be more complicated and expensive.

Another consideration, do you have power and cabling access where you would need it or what might be involved in addressing those.


Like Derek noted, you can treat the walls to limit reflections, but does that potentially make your situation even more different than that of the audience? While I understand the purpose of adding acoustical treatment behind a mix position at the rear of a room, I always find it somewhat incongruous to address it as a problem for the mix position but to then not address the audience in the same situation. If you do add some acoustical treatment, think of where it should be, if the speakers are up higher then anything hitting the rear wall at your ears or below is going to reflect down below to where you don't really hear it. There may only be a small band of height that actually directly affects what you hear.

I actually think that on center is not usually an ideal mix location, a bit off center or even midway between the center and side is typically more representative of what the majority of the audience hears.

I still stick by what I said though about there being no infill. It is a hollow space except for the concrete columns. I've been inside to to run the snake, you can easily move around.

The wall treating would make my situation more accurate, as instead of the fabric covered walls that line the house, it would now be concrete. Management might want to cover with the same color and fabric scheme, which I would be fine with. My only other concern would be that I would now be in somewhat of a differently shaped space than the audience, that's what I would want to treat for. Again, I'm headed up there now so I will try to take some pictures.

 

[museav]

I still stick by what I said though about there being no infill. It is a hollow space except for the concrete columns. I've been inside to to run the snake, you can easily move around.

The FOH position for the theater I work at is right behind the last row of seats. I'm somewhat crammed in with various folding tables as my "desk." We are getting a new board which is even deeper than our current one, and I think I've finally got the boss's ear about getting me some more space. The wall behind me basically covers up about a 4-5 foot deep hollow concrete space with 3 or 4 concrete supports that are holding up the actual booth above.

Okay, lets try again. There is a wall. What is the wall?

I took your original description to be that it was a wall that included 3 or 4 columns, the wall area between those columns would be the infill, it fills in between the actual structural members. It now sounds like the columns are actually in the space behind the wall rather than part of the wall.