John Sayers' Recording Studio Design Forum Archive

Hello all --

Years and years ago, I posted here looking for solutions for the low ceilings in my studio. John gave me the brilliant concept for my existing fabric ceiling, which has wowed just about everyone who has seen it. I'm eternally grateful he helped me make a *very* difficult space useable. The space has been more successful with each passing year, so... thanks!

In fact, it's be so successful, that I've outgrown it. I now need to build a bigger room to house larger equipment.

A question: one thing I did in my old space was to splay the walls to make a trapezoidal room. This helped tremendously with keeping standing waves to a minimum on the sides of the room. Is there a room size where this technique would start to have minimal ROI in terms of reflections? I am building in a new space that is 19' x 17', and can't decide if I should splay the side walls or not, and if so, at what angle to splay them. Shown here is a (very) rough sketch of the room. Ceiling is peaked cathedral type, sloping to the longer sides, 12' high at the peak.

Thanks in advance!
Carl

Hi Carl. Welcome (back!).

Please read the forum rules for posting (click here). You seem to be missing a couple of things!

In fact, it's be so successful, that I've outgrown it

Cool!

one thing I did in my old space was to splay the walls to make a trapezoidal room. This helped tremendously with keeping standing waves to a minimum on the sides of the room.

That's a common misconception, actually. Splaying the walls doesn't do much for modal response, but it does help for flutter echo if the total splay is more than about 12°, and it does help even more if you are trying to achieve a proper RFZ design. So from those two points of view, splayed walls are a good thing, but not for modes. Sure, if you angle a wall enough then the axial modes associated with that wall disappear, but by the very same act you create a number of tangential and oblique modes to replace the axials! That might or might not be useful, depending on many factors.

Is there a room size where this technique would start to have minimal ROI in terms of reflections? I am building in a new space that is 19' x 17', and can't decide if I should splay the side walls or not, and if so, at what angle to splay them.

Maybe you are actually asking the wrong question! It's more important to decide on which design concept you plan to follow for your room, then design the room around that concept. For example, if you decide on RFZ (which I strongly recommend, personally), CID or NER, then you pretty much have to splay your side walls (or part of them, at least), since that's the only realistic way of attaining the goals. But if you are going with some other design concept, such as the outdated LEDE design, or something entirely different, then you might not need to splay them.

There's also the issue of speaker mount. If you go with the (highly recommended) method of flush mounting your speakers (aka "soffit mounting"), then splaying part of the side walls is just a good idea, as it blends the speaker soffits into the room better, both acoustically and visually.

Finally, there's the issues of practicality, space, construction ability, etc. There might be other reasons why it would be good or not good to splay your walls, depending on the rest of the building, your building skills, etc.

So I'd suggest that you should first decide on the basic design criteria for your control room, along with any other rooms that might be around it, or associated with it, then based on that decide if you want to splay (or not splay) your side walls.



- Stuart -

Sorry about the rules not being followed to the letter there! I've added my location now.

This is all great info, thanks very much. I have decided that I definitely want to minimize flutter echo, and so I'm doing 13 degree splayed side walls on either side of the listening position. Here's my latest drawing.

Is there any benefit to making the front and back walls not flat, as well? And if so, what would be the best way to modify those walls?

Thanks so much!

Carl

Hey there --

Never heard back after my last post, but that's OK -- I've decided to leave the front and back walls flat and just treat them with absorbers (unless the back wall needs diffusion).

New question: the ceiling in the old studio was black vinyl insect netting, with black polyester sewing batting on top of that, with 703 suspended on wire between the joists above that. The batting was there to keep any insulation "shed" from raining down on me... and it worked (if there was any shed in the first place, of course, which I will never know!).

I'm wondering if literally *any* black fabric would work for this purpose, or if the batting truly is the best material for this purpose. I found a price online for black felt, for example, that was cheaper than the batting.

Thanks!
Carl

I'm wondering if literally *any* black fabric would work for this purpose, or if the batting truly is the best material for this purpose. I found a price online for black felt, for example, that was cheaper than the batting.

Pretty much any fabric should help with that, but what a lot of people do is to also put a very thin plastic layer between the insulation and the fabric, to keep the very fine fibers from filtering down. That also helps to keep the high frequencies in the room, so that you don't over-absorb them. The thinner the plastic, the higher the cut-off point for that, so if you are over-absorbing the high mids then use thicker plastic, and if you are over absorbing even lower in the spectrum, then use even thicker plastic.

- Stuart -