Just wondering what you are using?

I've always used Owens Corning 703 2" panels and built my own, but the stuff is nasty.

I've seen other materials out there, different foams, rock wools, cotton batting. What has worked well for you. The room is 17.5' x 19.5' x 8'10", I'm looking at covering 210 sq. ft. of wall space.

Thanks

I got some samples from SoundAway, which are cotton that has been treated to be less flammable. The specs are better than many materials, it's not like fiberglass WRT particles being circulated and entering eyes, lungs, etc. I have seen recommendations for Roxul, but have never used it.

Have you looked into using diffusion, rather than eating acoustic energy through absorption? How do you plan to arrange the areas that are treated vs left alone?

I have stacked stone columns in the room for aesthetics and diffusion. The front proscenium will be covered in stone as well. I have treatments arranged the best I could without looking stupid at what should be 1st and 2nd reflection points if my angles are correct. Then absorption along the back wall inset with paneling trimming it out.

I was looking at the roxul, studio pro acoustic foam, I found one called Eco-c-tex that has its performance rating listed being right around that of 703 for less money.

I've used some of the kits from this company.
Very easy to install any reasonable priced.

[Link: primacoustic.com]

Take a look at Bonded Logic.  I had a client that was against Owens Corning so used a lot of Bonded Logic's cotton fiber products (7 rooms worth).

[Link: bondedlogic.com]

Did use some Owens Corning in the ceilings, but wrapped all the panels in GOM fabric using spray adhesive, and then the panels were attached in place and then covered with another layer of GOM fabric using Questrac system.

Wrapping each fiberglass panel on all sides wasn't very cost effective, but alleviated the clients concern about fiberglass particles.

703 and rockwool seem to be used in music studios a lot, so it's pretty proven. It's going to ultimately be enclosed anyway.

Of course if you have the option, optimize the room itself first, and the listening position. That'll get you an immense amount of benefit before you even start treating, and therefore will require less treatment. Make the walls non-parallel if you can. Tilt the window panes if you can. Calculate the proper listening position to keep it out of as many room modes as possible, which can get the number of modes you have to deal with via treatment down to a minimum to start with.

If you have really narrow, deep frequency issues maybe consider tuned treatments instead of absorption. That wasn't something I ever had the chance to play with, but it supposedly works well for that sort of problem.

And obviously don't guess. Use the correct software and microphone to measure the response at the listening position and use that to find the best position, and then play around with the raw materials to see what gives you the best bang for the buck in particular locations.

I'm building out a finished square all drywall room. Going to make it not square, I can put the treatments wherever I want. No windows, but there is a double door that has to stay.

The client wants at least 10 seats which is going to dictate the seating arrangement. The room is 19' deep so the back row is going to be against the back wall.

I'm probably over thinking this, the room is a massive echo now, but it's almost square so shrinking it to 17.5' wide will help. I've done more than a few complete theaters like this, but this one has given me more budget than any other and I want to consider everything I can.

I would determine the typical SPL and factor in some headroom in the room before anything else- the amount of absorption will depend on this because a live room won't be terrible at low SPL unless the sound has a lot of sharp transients like gunshots, drums, etc. At High SPL, first reflections won't be enough, but distance between surfaces can be your friend and if the speakers are far from the side walls, you may be able to prevent some of the mid-range flutter, but the low frequency could be trouble unless something can be placed in the corners to break up the energy.

I was surprised by the small theater I recently finished in the ballroom- while not what I would consider 'great', it was still good at -10dB on the AVR-X6200 volume scale and the SPL was high enough that it shouldn't seem to be inadequate for a relatively realistic movie experience.

I don't know if you have used Room EQ Wizard, but one of the new tools is a room simulator that lets the user set the room dimensions, place main & surround speakers and multiple subwoofers, in three dimensions- this is great because the height makes a big difference in the predicted response and it shows notches from room modes. It also works well for RTA and it's what I used when placing the panels in my room when the sound was pissing me off. I had a deep notch in the usual area and it's now gone. The response is very smooth and the only reflections that annoy me would be hard to treat because they're coming from the side of a kitchen cabinet.

I looked into making my own but found out you really don't save much. Bought from [Link: gikacoustics.com]
Pricing was very reasonable.  They also have what they call art panels (haven't bought any though) that look really cool.

BTW, maybe you meant this by 'not square', but really it means non-parallel walls. If it has to be parallel walls, then obviously having no two axes be the same length or multiples of any other shorter axis length is good. But really you want non-parallel walls if you can. If you can create a non-flat ceiling that's good, and usually gets rid of a hard wall/ceiling corner. If you can make the two side walls not be parallel, that would be really good.

If you get rid of the four corners that's good. You can actually get double duty there. Round them inwards (like a section of a small column stuck through the wall), and stuff that shape with rockwool to absorb bass reflections out of the corners as well. The rounded shape will diffuse the more mid-range frequencies, but the low end stuff will just go straight through it unless it's made of solid concrete or something, which it won't be in your case. So it's a double duty way to get absorption and diffusion in the corners, and it can look nice as well according to how they are done.

This an area our company specializes and there is not a one trick pony for every situation. Acoustic treatments will usually use a combination of absorption and diffusion. Owen 703, Rockwool and Roxul are not the best solutions, they have limited frequency range unless you make them much thicker. Non-parallel walls do not solve room mode problems, only move them to different locations and the various type of reflections still need to be calculated. Square rooms can work but placements are more critical.

There are so many factors to cover it is just impossible to give good suggestions. Speaker dispersion comes into play and will determine the type and locations of acoustic treatments. Seating, subs, room layout, type of speakers, etc. The best advice I can give with no disrespect is the often quoted "Hire a Pro".

If you are looking for a design plan for just the acoustic treatments and layout in the room and not construction, I would try Quest Acoustics or PMI Limited. Primacoustics and Auralex do some free layouts or give advice but no where near as good as the other mentioned. But, if budget is tight. They don't factor the type and dispersion of speakers. I would say they are more generalized and not as precise.

Isn't the purpose of non-parallel walls, obviously not to get rid of reflections since it can't do that, but to help make sure that what comes back to you has A) gone a more circuitous route which reduces its energy more (particularly if it's hitting absorbers and diffusers along the way) and B) delays it more help ensure that what does come back to you is less of a direct reflection of what is coming at you from the speakers, which is where the biggest problems arise.

On the issue of thickness, that's sort of less of an problem if you are building, since you can recess it into the walls. So you don't have to have it sticking out into the room necessarily. Build the actual room, then you can fill the whole back and front walls if you want, and put a secondary 'wall' over that, which may be mostly fabric cover. You can put a diffuser on the rear as well if you want.

You can do similar things with the corners, where it doesn't look like treatment, it's just a non-square corner that looks like the rest of the wall (or looks tastefully not like it if you want.)

There are various ways to do it and make it look nice, while still getting, maybe 6" or 8" or more of thickness. That's not the end all of treatment obviously, but it would make a tremendous difference compared to the average person's home theater response.

Obviously, if you have the bucks and experience and tools, you can super-tune a room. But there's a lot of info out there, and if you learn the diagnositic tools and experiment, you can make a huge difference on your own. You can move the materials around and make comparisons before you commit, so you don't have to guess or even theorize (though the theorizing can guide your experiments clearly.)

Non-parallel walls prevent standing waves by not allowing reflected sound from reflecting directly into the incident sound but when the angle is insignificant, it doesn't do much- better to keep it simple from a construction standpoint and just use absorption and diffusion. I haven't been in a studio that used non-parallel surfaces that were less than 10° off, which would be hard to justify if WAF rears its ugly head.

The thing about super-tuning a room- that all goes out the window as soon as people enter and start absorbing sound.

Here's a few photos of the back wall from a room I finished earlier this year that will maybe offer up some ideas.  Back wall is a set of 4 RPG Modex Edge bass traps, the projector soffit is RPG FlutterFree diffusing panels mounted in a wavform shape, the ceiling is RPG Waveform Spline with a custom wood finish and was also routed with holes to provide diffusion and absorption (Splines were filled with Bonded Logic).  The walls are Bonded Logic with RPG BAD panels in strategic locations for some diffusion.  The back wall and ceiling also has 2" Bonded Logic absorption behind the RPG products.

We even built out angled panels around the rear subs that were rectangular...

The front has a false speaker wall built out about 3ft  that angles out to the corners with lots of absorption behind.

Dave, check out RPG