Control room walls materials ?

[GMR]

I'm finishing my studio walls, It's on gyprock now. What materials would you suggest is good to cover this to have a good sounding room. I've been looking at pics of various control rooms but hard to see what they used. I see wood type coverings alot and some kind of felt type materials. What is it you guys use! Also what do you use on ceilings!

Any suggestions apreciated

[audiothings]

the covering is not the most significant factor when it comes to a "good sounding room". true, the more soft things there are on the surface (foam, curtains etc) the more hf will get absorbed, but its only hf and hf is relatively easy to treat. there is a lot of mathematics and physics involved in studio design and i recommend that you seek the help of a professional acoustician.

my .02,
self.

[Anderson]

On the projects I'm working on, we mostly use a Gyproc sandwich + a resilient material layered in it a lot, and just paint it. This is usually the "final layer" of the sound proofing & basic room shaping. You can put wood, but that would be more for looks than for actual sound - wood will absorb slightly more than Gyps boards in the HF... but less bass, depending on the type of wood and the thickness.

What you want to do is to use many diffraction panels & systems, and at least a couple resonators tuned to your room. Don't use curtains, foam, and avoid cork etc...

You can build your resonators and other panels yourself if you think you can handle the (heavy) calculations and the construction. My advice is to ask an acoustician. Around 75% of the clients I have that decided to do it on their own came back to me and asked for my company to design new panels. But then the budget is not the same...

Good luck and PM me if you need help!

[Jules]

Mix up the surfaces..

All one type = horrible

In mine

3 walls = Fabric covered glassfiber + MDF fake wooden panels
1 wall = concrete / Peg board / fake book shelves + MDF fake wooden panels
Ceiling (angled from floor) = hard surface + some accoustic trapping
Floor = thick wood laminate floorboards
+ 2 untreated wooden doors
+ Large leather couch acts ass bass trap
+ Side walls have 2 floor to ceiling bass traps

[Ethan Winer]

G,

> What materials would you suggest is good to cover this to have a good sounding room. <

It's not so much surface treatment as a system of absorption (and possibly diffusion) that's uniform across the full range of frequencies. This means bass traps in as many corners as possible, mid/high frequency absorption at the first reflection points, and additional broadband absorption on any large areas of bare parallel surfaces. I don't disagree with the advice to consult a pro if you have the budget, but you can learn a lot about this stuff for free from my Acoustics FAQ:

www.ethanwiner.com/acoustics.html

--Ethan

[GMR]

So you are saying that all these control rooms I see in Pine wood is not really for sound benefits! interesting to know! But does pine wood reflect sound like Gyprock which gives a room an annoying "zing" to it. Cuz I'm considering pine wood planks.

Thank you, and if there are more suggestions I'm willing to learn!

[jajjguy]

The "zing" (also called flutter) that you attribute to gyprock is probably more due to the fact of hard, bare, parallel walls. You'd get a similar zing if the walls were wood or whatever.

Ethan's suggestion of broadband absorption on any parallel walls is the right approach for this particular problem. (Angling the walls would be even better, but that gets complicated...)

As a separate question, does gypsum wallboard sound different from wood paneling? Yes, but the difference between gypboard and wood is not likely to be as great as the difference between angling the walls and not, placing broadband absoprtion in the right spots or not, or even the spacing of wall studs, the number of layers of gypboard or thickness of wood panels, whether there is insulation in the wall cavity, etc. These are less visible and less exciting than "gyp or wood" but just as important, or more important.

[Ethan Winer]

Jajj,

> You'd get a similar zing if the walls were wood or whatever. <

Exactly. Any differences will be small, and only at the very highest frequencies where wood may reflect a tiny bit more than sheet rock.

Also, since I know you play the cello, I'm in the final phase of a pretty cool cello video. If you email me I'll send you a link to the video when it's done in a few more weeks.

--Ethan

[jayfrigo]

As has been stated, there are several materials that are usually used in conjunction. Some areas have wood, some are plain drywall, some have stone, and all have soft and absoptive surfaces in places as well.

Typically, fabric is extensively used on wall surfaces in studios. What's behind the fabric is not always the same. The most popular fabric is Guilford 701 from Guilford of Maine. It is a coarse weave that lets sound pass. Behind it often goes compressed fiberglass, most commonly Owens-Corning 703. Sometimes there is perforated board, or "peg board" with the 703 behind it, and often an airspace behind that. Sometimes the fabric is over "sound board" which is basically a limp rigid fiberboard of some type. It's a little dryer than wood or drywall, but still somewhat reflective. Soundboard often used behind the gypsum for more isolation, or as part of a resilient channel system. Celotex is a common supplier. Sometimes the fabric covers thin sheets of plywood, behind which is a small airspace, a layer of 703, and a larger airspace. This functions as a membrane absorber for bass frequencies.

All of these treatments are designed to control certain frequencies in selected places. You typically want to eliminate first reflections at the listening position, so the soft surfaces are strategically placed to control that. These soft surfaces, usually 1" or 2" thick 703, but sometimes upto 4" thick (foam products are sometimes used in budget applications), are better at controlling mid and high frequencies. That's why some of the other treatments should be included to absorb bass frequencies. Don't use too much absorption as a completely dead room will do you no favors. You can also make angled plywood reflectors to direct sound away from your listening position if the room is too dead. When deciding where to treat, remember, the angle of incidence equals the angle of reflection. Have a friend move a flat mirror around the wall while you sit at your listening position, and wherever you see speaker drivers, you'll want to treat. Don't forget the celing!

If you really wanted to target the proper bass frequencies to absorb, find a room mode calculator on the web, enter your dimensions, and treat frequencies where multiple modes from the three dimensions tend to be very close together. There are formulas for the membrane absorbers and peg board style helmholtz absorbers that allow you to construct them to zero in on those frequencies. In a membrane absorber, the depth of the cavity, usually based on a quarter wavelength of the frequency you are trying to absorb, is quite important, as is the thickness of the plywood. The percentage of surface area covered by perforations influences the effective frequency of the "peg board" style helmholtz absorbers. The fewer holes, the lower the effective frequency. Another similar treatment is slat absorbers where long boards are spaced at certain distances over a cavity.

If you don't want to get into the math and the precise construction, just put some regular peg board over some 703 and leave a couple inches of airspace behind it. Cover with 701 fabric. That will function as a basic broadband absorber and give you some help without too much effort or expense.

The thing we haven't touched on is diffusion. There's plenty of math involved in really targeting diffusion (do a search for Schroeder equations) but you can just bend some 1/4" plywood and make some basic polycylindricals to provide some basic scattering. If you seal them and put fill in them, they'll also absorb some bass.

So, to sum up, use a combination of surface treatments and techniques. Mix it up with absorption, bass trapping, reflection, and diffusion. You certainly could run the numbers and do precise construction, but you can still make some tangible improvements without getting so complex. Obviously acoustics is a huge and complex subject, and this just scratches the surface, but hopefully it provides an overview for you and will help you start thinking about ways to make your room sound better. Good luck!

[Jules]

Wot he said

[Anderson]

I think all has been said...

For a start, If I were you, I would have my room shaped by an acoustician. That's N°1 rule: optimized shape!

[MIKEHARRIS]

Soft...easier when you bounce off em