Control Room -Acoustics Advice Needed

[liveammodigital]

Hello All-

This will be the first of a couple of informational posts concerning our control room at Livingston High School in Livingston, NJ.

We have just installed a control room at the school where I teach on basically a shoestring budget. All of the equipment is in, and it was fit into an already existing space that is also occupied by a TV 1 class. As you can see from the pictures, the room has three right angle corners, and one angled corner. The pictures, in order from bottom to top, show from the mix position, moving clockwise around the roomThere is also TV equipment placed throughout. I am aware that this is not by any means the ideal control room, but it is what we have.

As far as construction materials go:

1) There is a raised floor with access tiles that can be removed. Great for running and hiding lines.
2) I am assuming that the studs are metal, covered with fire rated sheet rock and no insulation in between....again nothing I can do about this.
3) Ceiling is a standard drop ceiling outfitted with what appears to be Armstrong 2' x 4' acoustical tiles.
4) Concrete block left and right walls as can be seen in the photos.
5) Room is surround ready.


The givens:

1) The room can not change
2) Equipment position for the most part can not change
3) We have a fair supply of Auralex Studiofoam absorbing surface foam, Metrufusors, and QFusors
4) Volume not a problem for neighbors

The problem: Where to apply absorption/diffusion using the Auralex products we have on hand.

My next post here will be a drawing of the room giving perimeter layout, ceiling heights and equipment positioning dimensions.

Please let me know if there is anything else besides the drawing that I need to provide. I am more than happy to provide detailed photos, etc.

Thanks much,

Amedeo Ciminnisi-Instructor

[Soundman2020]

Hi Amedeo, and Welcome!

That looks like a nice 5.1 setup you have there, in terms of equipment, but I'm pretty sure the room can't sound too good the way it is treated at present.

1) There is a raised floor with access tiles that can be removed. Great for running and hiding lines.

Yes, but not so great acoustically! That space down there is a resonant cavity, and is not helping your room acoustics at all. Is this the typical type of "computer floor", often also used in post-production houses and TV facilities? Is it also a "plenum" type floor, with air conditioning running through there, and up through grills in the floor?

3) Ceiling is a standard drop ceiling outfitted with what appears to be Armstrong 2' x 4' acoustical tiles.

Can you lift a tile and see what is up there? For example, is there any insulation up there? HVAC ducts? Cablig? And how much space is up there, between that false ceiling and the real ceiling?

5) Room is surround ready.

Yes, but your rear speakers are in totally the wrong position for that. They should be much further out to the sides, and not directly behind you. ITU, EBU, Dolby etc. all recommend the same thing, more or less: 100° (min) to 135° (max), with 110° to 120° seeming to be preferred.

The problem: Where to apply absorption/diffusion using the Auralex products we have on hand.

You don't mention how big the room is, but it looks to be too small to be able to use most types of diffusion, and give the amount of "clutter" from the other unrelated equipment in there, there's probably plenty of diffusion going on already. Numerically-based diffusion needs a lot of distance between the diffuser and your head, in order for the artifacts to smooth out and merge, and most studios just are not big enough for that. So diffusers are probably out of the question. (Of course, the manufacturers of diffusers often "forget" to mention this issue when you buy them...) The only exception would be if you only use diffusers that are tuned to very high frequencies.

But diffusion is not going to be your biggest problem: Bass trapping is. In any small room you need a lot of bass trapping, so that should be your first priority. It would help to have that diagram you mentioned, to see the exact shape and dimensions of the room, but it seems that all of the vertical corners are already occupied, so you'll have to use the horizontal ones. You seem to have space on all of the side walls, and the front and rear walls, to do that, in the wall/ceiling corners. I'd suggest simple DIY corner traps across all of those corners, or at least as many as you can get to.

I would also put thick absorption across the entire rear wall: At least 4" of 703 (preferably 6"), and spaced away from the wall by several inches as well.

You should also have absorption in several other places in that room, especially seeing that you want to do 5.1 work in there, but it would be better to see the accurate floor plan first.


One other big question here: Is the room set up symmetrically? In other words, are the desk, chair and center speaker all on the center line of the room, equal distances from the left and right walls? If not, then that is a major problem. Symmetry is critical. It is hard to be sure from the photos, but it looks like everything is closer to the left wall than the right wall: If so, then it would be really, really recommendable to move those things over to get on the center line: If you can't do that, then you won't be able to produce mixes that "translate" well to other listening environments, such as living rooms, cars, MP3 players. Symmetry is essential, not just for the stereo image and sound stage, but also for EQ and other issues.

- Stuart -

[liveammodigital]

Hi Amedeo, and Welcome!

That looks like a nice 5.1 setup you have there, in terms of equipment, but I'm pretty sure the room can't sound too good the way it is treated at present.

1) There is a raised floor with access tiles that can be removed. Great for running and hiding lines.

Yes, but not so great acoustically! That space down there is a resonant cavity, and is not helping your room acoustics at all. Is this the typical type of "computer floor", often also used in post-production houses and TV facilities? Is it also a "plenum" type floor, with air conditioning running through there, and up through grills in the floor?

Yes. This is th typical kind of computer room flooring I am sure you have seen before. There is nothing under there but cabling, both electrical and signal.

3) Ceiling is a standard drop ceiling outfitted with what appears to be Armstrong 2' x 4' acoustical tiles.

Can you lift a tile and see what is up there? For example, is there any insulation up there? HVAC ducts? Cablig? And how much space is up there, between that false ceiling and the real ceiling?

I am going to have to check and see what is up there, and how much room there is. I will attempt to supply allof this info with my next post that will include a drawing with measurements, equipment layout, ceiling heights, etc.

5) Room is surround ready.

Yes, but your rear speakers are in totally the wrong position for that. They should be much further out to the sides, and not directly behind you. ITU, EBU, Dolby etc. all recommend the same thing, more or less: 100° (min) to 135° (max), with 110° to 120° seeming to be preferred.

Yes. I obtained a surround document from Michael Frondelli. It was a helpful document. Unfortuantely, this being an institution, I did not have to much to say in the allocation of space for audio/video. I suppose to teach concepts, this is great, but to work on advanced concepts, I know that at this point, we will not be hearing what is really there. Frustrating.

The problem: Where to apply absorption/diffusion using the Auralex products we have on hand.

You don't mention how big the room is, but it looks to be too small to be able to use most types of diffusion, and give the amount of "clutter" from the other unrelated equipment in there, there's probably plenty of diffusion going on already. Numerically-based diffusion needs a lot of distance between the diffuser and your head, in order for the artifacts to smooth out and merge, and most studios just are not big enough for that. So diffusers are probably out of the question. (Of course, the manufacturers of diffusers often "forget" to mention this issue when you buy them...) The only exception would be if you only use diffusers that are tuned to very high frequencies.

Thanks for this comment. This definitely will save me trouble.

But diffusion is not going to be your biggest problem: Bass trapping is. In any small room you need a lot of bass trapping, so that should be your first priority. It would help to have that diagram you mentioned, to see the exact shape and dimensions of the room, but it seems that all of the vertical corners are already occupied, so you'll have to use the horizontal ones. You seem to have space on all of the side walls, and the front and rear walls, to do that, in the wall/ceiling corners. I'd suggest simple DIY corner traps across all of those corners, or at least as many as you can get to.

Thanks. I am going to seek out some bass trap designs. I am a very handy guy, so I will be able to build these, I am sure. We also have a great stagecraftdepartment that I am sure would be interested in helping out.

I would also put thick absorption across the entire rear wall: At least 4" of 703 (preferably 6"), and spaced away from the wall by several inches as well.

I am not familiar with this material, but I am going to look into it.

You should also have absorption in several other places in that room, especially seeing that you want to do 5.1 work in there, but it would be better to see the accurate floor plan first.

Great. I will get this posted ASAP!! Thanks so much for all of your valuableinput. At this school, I am basically a one-man act, but administration is supportive of the program. We are very lucky to have what we have. Now, i just want to improve upon it if we can, in order to get it to be the best it can be without too much expense. Again, many thanks!


One other big question here: Is the room set up symmetrically? In other words, are the desk, chair and center speaker all on the center line of the room, equal distances from the left and right walls? If not, then that is a major problem. Symmetry is critical. It is hard to be sure from the photos, but it looks like everything is closer to the left wall than the right wall: If so, then it would be really, really recommendable to move those things over to get on the center line: If you can't do that, then you won't be able to produce mixes that "translate" well to other listening environments, such as living rooms, cars, MP3 players. Symmetry is essential, not just for the stereo image and sound stage, but also for EQ and other issues.

- Stuart -



Stuart...unfortunately, no. We are not symmetrical in that room. This layout was essential in order to accommodate the ADA act and in order to have room for a classroom full of kids, etc.I was wondering, if for more critical mixing situations, etc, if we could possibly make use of gobos as sort of a FAUX right hand wall? What do you think?

[liveammodigital]

Here is the floor plan of the control room. I am willing to provide further measurements. There is about 1 foot of space above the drop ceiling. The scale is 1 block=1 square foot.

Thanks much,

Amedeo

[Soundman2020]

Well, there doesn't seem to be much that you can do about symmetry, which is a pity as it means you won't be able to get an accurate soundstage and stereo image, and your mixes won't translate well, but it is what it is. So it seems that all you can really do here is to apply some treatment to the room, but even that is not an easy task, since the room layout and the other equipment in there do not allow you to put it where it needs to be!

What I would suggest is a large horizontal superchunk on the front wall, in the wall/ceiling corner, all the way across the room, another one across the top of the rear wall (that strange curved white "thing" on that wall will have to be moved), then thick, deep absorption across the entire rear wall, at least 4" thick (6" would be better) spaced several inches away from the wall, and a thick cloud over the console/mix position. Also, remove those diffusers in the ceiling: they are way to close to the mix position, and are doubtless making things even worse.

There's no point in trying to do the first reflection points, since they seem to be located where the other unrelated equipment is, and there's no more space for bass trapping either, even though you need a LOT more of that.

So that's probably about as good as it can get. I reckon it is worth doing, as it will improve things noticeably, but it won't make the room perfect by any means, due to the underlying issues.


- Stuart -

[liveammodigital]

Stuart-

First of all, I want to say a big thank you for taking your time to look at this project. As I figured, there is not much that can be done here, but I will try to implement your suggestions as far as the absorption goes.

One question: Is it worth building some vertical bass traps? Where would you recommend purchasing the absorptive material from? We are located in Nutley, New Jersey, USA

Will eventually post to let you know how it all turns out.

Thanks

Amedeo

[Soundman2020]

One question: Is it worth building some vertical bass traps?

If you can fit them in, then certainly! Like all small rooms, that room will need plenty of bass trapping, which is why I suggested the horizontal superchunks, but if you have space to put in vertical superchunks in the corners, then that would certainly help a bit more.

Where would you recommend purchasing the absorptive material from

Just get some plain old Owens Corning OC-703 from your local Home Depot or equivalent, cut that into large triangles, and stack them in the corners, floor to ceiling. Build a simple wooden frame around it, and stretch any type of breathable cloth across the front, for aesthetics. "Breathable" simply means that if you hold a piece of the cloth over your mouth and nose, then you can easily breath through it without noticing any resistance. The cloth can be any type, style, color, thickness, etc., as long as it is breathable. Simple, low-cost and very effective.


- Stuart -