Control Room Shape Design: Does symmetry trump all?

[soundbarnfool]

I'd welcome any comments, however brief, general or specific...

[uros]

Hi,

I do not have too much experience but I have a lot of theoretical knowledge and I have been involved in building one professional studio.
I have made a picture (quite simple one) (it is attached) because I thought that it would be easier for me to explain what I want. This is type of construction is known as cockpit and it is totally opposite to LEDE principle.
Bear in mind that ceiling should also be angled at 12 degrees, if I am right (being higher at the back).

If you have any further considerations be free to ask.

Hope that I was helpful.

Cheers.

[Adam Dempsey]

Originally Posted by soundbarnfool

my question: is the concept of symmetry MORE IMPORTANT than the potential early reflection issues?

In my (non-acoustician) opinion & experience, I'd consider the two aspects equally. Symmetry does play an important role in helping achieve a 3 dimensional sonic image.
In combination with (broadband) absorption and diffusion you'd be a long way to a decent sounding room.

[jayfrigo]

As you rightly observe, there are so many variables and so much complexity as to make any brief answer woefully inadequate... but here goes nonetheless!

Symmetry of the inner shell for control rooms is extremely important. With your dimensions, you are going to have some compromises no matter what. It's usualy better, all things being equal, to have monitors on the short wall shooting into the long dimension.

However, this isn't strictly necessary. Properly planned and treated, many control rooms with very large consoles work fine the other way around. There are even some conditions under which one might recommend monitors on the long wall, some consumer home situations coming to mind. Anyway, you'll definitely have to treat for early reflections, and no matter how you orient your room, with a 10' dimension, you'll have issues to contend with. Here's where all the complex options come up, so I'm just going to leave the comments there for now to prevent my typing all night...

[soundbarnfool]

thanks fellas! i'm gonna try to angle the side walls a bit too, sort of like in the diagram above...

[Nordenstam]

Am not an expert, though I believe angling them wont help much if they're not angled enough. Enough to reflect the sound waves away from the listening spot. An arbitary small angle may be a lot of work without much result.

I think Uros referenced to a Reflection Free Zone. Like a stealth fighters splayed surfaces, the angled walls leads the first reflections away from the listening sweet spot. Perhaps you'll find some interesting info by googling the RFZ term, and/or get the much recommended Master Handbook of Acoustics by F.A. Everest.

[Ethan Winer]

Originally Posted by soundbarnfool

I have read that with rooms of this dimension it is better to have speakers along the longer wall, but I have also read that it is better to have them along the shorter wall.

It's always better to have the speakers on the short wall firing the longer way down the room. Yes, it puts the side walls closer to your ears, meaning those reflections are "early" and must be treated, but that's very easy to deal with. The overwhelming advantage of the "long way" is it makes the bass response much better. Fixing bass problems is much more difficult than treating early reflections! So it's best to start with the orientation that gives you the better bass response.

is the concept of symmetry MORE IMPORTANT than the potential early reflection issues?

They're both equally important. What happens behind your head matters less though. Left-right symmetry is needed most in the front of the room, and especially the area between your ears and the loudspeakers.

See this article on my company's web site for more:

RealTraps - How To Set Up a Room

--Ethan

[soundbarnfool]

Thanks Ethan (and all), I've read your very helpful info!

[jayfrigo]

Originally Posted by soundbarnfool

thanks fellas! i'm gonna try to angle the side walls a bit too, sort of like in the diagram above...

If you want to alter the room geometry without sacrificing too much of your limited width dimension, you can use what I jokingly call "wedgie walls." These are essentially side walls that are shaped as sawtooth waves.

This allows you to get enough angle to aim reflections where you want them without losing several feet of width. You also can build each triangular shaped protrusion as a variable depth bass trap.

This technique is good for increasing the size of the RFZ, advantageous geometry, bass trapping, compatibility with 5.1, and fitting into the contraints of existing rectangular rooms, which has a side bonus making mode predictions simpler too.

I don't use this technique for every project, but I do use it often, especially given modern studio conditions where there are often multiple-use media rooms, and they need to work in existing spaces without building from the ground up. Here are a few links to examples of rooms I've used the technique in:

Mastering studio in Los Angeles

Mastering studio outside Boston

Multiple use college studio

[soundbarnfool]

So you'd use maybe 703 on the wedgie walls?

[jayfrigo]

Originally Posted by soundbarnfool

So you'd use maybe 703 on the wedgie walls?

The beauty is that you can use so many different things on the wedge surfaces. You could simply have 703 on the front, a little airspace, and some fluffy fiberglass in back, or you can use plywood to make diaphragmatic absorbers that reflect highs, vinyl for membrane absorbers, or you can use perforated panels for Helmholtz absorption, and you could even space 703 in front of the perforated panel to add mid and high absorption. You can also use something like celotex soundboard for something that doesn't reflect as much mid/high as ply, but is certainly not as dead as 703. Sometimes just building the wall with drywall in the shape will do what you need. You can then treat on top of it as you would a normal wall. It's very flexible in implimentation.

And remember, you don't have to use all the same kind in the same room. You may want perforated panel in front, perhaps covered by 703, and then a regular 703 box on the side of the console to handle first reflections, but perhaps gradually moving to harder and harder surfaces as you move toward the rear of the room where you start to diffuse. Once covered with fabric, it looks uniform, but I can assure you that in the rooms in those pictures, what's "under the hood" varies. Some even have different surfaces within the same wedge.

It depends on the whole room plan, including geometry for reflection, bass trapping, first reflection control, and overall reverb time desired. If you don't mind a bit more complexity, you can even add varying degrees of diffusion in a number of ways, from flutterfree, to BAD (Binary Amplitutde) panels, or other methods.

OK, now you know my secrets! Use them well and remember me when...

[No4PCs]

I did my control room totally assimetrical design with some bass traps ( After read GS opinions by 1 year ! )

[random sunrize]

Originally Posted by Ethan Winer

Left-right symmetry is needed most in the front of the room, and especially the area between your ears and the loudspeakers.

--Ethan

Is the reasoning behind this to improve stereo-imaging?

[Adam Dempsey]

Yes, both stereo and depth imaging.

[No4PCs]

I did my control room totally assimetrical but not in the monitors place.
In monitors place wall totally simetrical.

[soundbarnfool]

Originally Posted by jayfrigo

OK, now you know my secrets! Use them well and remember me when...

You are a gentleman and a scholar. Thanks for sharing...

[rufus13]

Mono room more forgiving. Most program material is all-mono or mostly-mono, even though delivered on formats with potential for wide channel differences.

2 channel stereo never provides "solid" center (for more than the theoretical listener in the "sweet spot"), 3-channel "stereo" is not distribution standard, but provides far superior listening for a small group.

I think that you are right to place loudspeaker on long wall to give side reflections more time and distance to diminish.

Cheers.