Acoustical Treatments Master Thread - Page 214

Yes one might end up with a band a foot or two tall across much of the front. Of course, existing screen placement may mean one cannot really treat everywhere the mirror says. Nothing is perfect and I'd choose to be able to see the screen rather than cover part of it with panels


That's a REALLY GOOD idea to explore, if the budget for a new screen exists.

The only *treatment* in the theater is the zebra carpet (not my choice) and the Berklines....so no, no treatments. That's why I am wanting to experiment with adding some, as it did improve my last theater's acoustics and I'm sure it can improve this theaters too.

Yep, I used the mirror in my last theater to find FRP's..just hadn't done it in this one. You're right, it's cheap and could be quite telling. Thanks!

-Jason

Thanks for the info Jasplat. I have an AT screen and will build mine accordingly. I wasn't too keen on the zebra look either but the rest looks nice even though varying from textbook. I think treatments where your thinking about may unfortunately be necessary for the both of us. Good luck!

After doing the mirror test tonight, I am developing a plan which I think will be a good compromise between acoustic improvement and keeping within the design of the theater. I'll let it be a supprise and post photos when I get it done (I'll be ordering supplies tomorrow). Of course, I won't know exactly what improvement it will make until I take some measurements which I also plan to do, but if nothing else I should benefit from the placebo effect.

BTW, the side walls only had very small areas where there were first reflection points. The ceiling and back wall will benefit from some treatments as well.

The zebra carpet we inherited with the theater has grown on me, the wife hates it. It's not worth the $750-1000 it would cost me to replace....so it's staying. Keep us posted on your theater's progress. Best of luck!

I'll keep you posted! I am looking into the details of design presently and the view of your theater really helps.

Also, How do the side surrounds perform? I noticed their inwalls and appear to angle downward. I have larger ribbon direct speakers from soundsalk and will probably bracket them partially inwall facing straight over the head. Thats my thought at the moment anyway. They are a problem for me but I'm sticking with them and will need to compromise aesthetics for their placement.

I am looking forward toward seeing the results of your acoustic efforts. Good luck and I'll keep my fingers crossed!

In the plan I'm having to deal with, there is a one-foot deep acoustically transparent false wall along the front where I could place some corner bass traps. Since they don't have to be triangular (as they'd be hidden from view), would it be best to use two 2' wide by 6" deep OC703 (2" thick) square "pillars"?

I could probably do regular 17x17x24" triangular "chunk" traps in the back corners. I need some "aesthetic value" there.

I have 10' high ceilings in the plan I'm dealing with.

Any other suggestions than that? Thx.

I searched and couldn't find anything on this which suprises me, but did anyone else notice a relatively strong smell from their linacoustic? Mine smells almost fishy and is really quite strong in the basement and in the garage where the roll is.

It wasn't very noticeable while in the plastic bag unless up close, but is now that it is open and exposed to the air.

Let's not go over the top absorbing everthing...diffusion is more likely required. What speakers you using?

Absorption is not the solution to every problem and is over used and over used.

My roll does not have any smell. I really don't think it should smell; it is intended to be installed inside air ducts after all. Maybe you got a bad batch? I would contact Johns Manville.

It is possible you'll have a smell ... it's put in plastic at the factory and hasn't had time to air out. It will be fine in a few days.

No smell here. Sounds like yours sat in a damp environment and developed mold. Not good. I'd spray it with something to kill the mold. Mold in the home can be a health hazard.

I cant speak to linacoustic but when I opened the 703 it had a strong ammonia like smell that dissipated after a few days.. I've seen others comment on similar experiences.

The odor is most likely the binder used that was not completely baked off/cured in the manufacturing process, the remainder is outgassing and producing the smell and should dissipate over time.

I believe the Linacoustic is 1.5lb pcf and the OC is 3lb pcf so I would assume the have different absorbtion properties for sound.

I will have some leftover Linacoustic and wanted to create some corner"super chunk" bass traps with it but I'm not sure if it will work very well compared to OC703 or OC705.

Does anyone have any comments regarding this?

So i havn't read all 300+ pages. I'm in the middle of building my theater in the basement. Here's the general stats

Room Size: 15' front wall, 27' side walls, 9' high
sitting distance 10'/16'/19' (table)

my question is, since i'm about to finish up framing: instead of hanging the sound absorbers/diffusers or what ever the owen corning 703 with fabric around it is, can i build them into the wall so they are flush with the drywall?

I would prefer to have a cleaner look

thanks
pete

Nope ... not if you want any form of sound isolation at all. But...there is a way.

Hmmm...very cryptic. What is that way?

Room within a room.

No, not room within a room. Sorry I can't be more specific.

Can you tell us WHEN you can be more specific?

Please take note he said not with sound isolation because the lack of the drywall would allow sound to travel out of the room much easier.

I believe they would still help improve the SQ of the room, but would only absorb from the front rather than the front and sides. So less overall impact.

There are various techniques, tricks, methods, we've developed over the years which we would prefer to keep proprietary. Many of those have to do with how we get the treatments installed without looking like we have treatments installed. I do believe, however, I've posted enough "in the rough" photos for it to be sorted out by a clever lad.

I can't speak for Dennis, but I had an idea (I haven't tested it, so use at your own risk):

If you strip your ceiling or wall down to nothing but studs (or joists) and the drywall behind the studs (or floor above the joists), you could drywall the inside of that cavity, perhaps decoupling that new drywall w/ standoff clips or strips. Then, you could fill in the newly drywalled, slightly reduced in volume cavity w/ whatever fiberglass or other treatment you want, and then cover the whole thing w/ GOM or equivalent.

It's a lot of work, but I might give it a shot, as I currently have everything exposed in my theater room.

John

This has me scratching my head. Doc Pete never mentioned anything about needing acoustical isolation, only acoustical treatments. If he doesn't care about isolation, he most certainly can build treatments flushed into the walls. And, if he has the space and if the walls are already constructed to the point where redoing them is too much of a pain, it can be done as a room within a room, i.e. mount the treatments, install studs/furring strips and cover the entire area with an acoustically transparent material

Some interesting stuff posted here, will look into some of this in the future.

Frank

So i don't know the proper terminology, but now that i think about it the panels i wanted to place flush with the drywall would be used for diffusing early reflection (i think diffusing is taking the source sound and when it hits the material it scatters it in multiple directions).
So i understand why Dennis wouldn't want to give away all his tricks since that's how he makes money... i understand that as a professional myself.
But i think to used my idea i would need to drywall a "slot" or recessed area for the diffuser to sit into. That is to block out sound from traveling through the diffuser to the next room and vice-versa.
I'm trying to do what acoustic work that i can do/understand/afford. I"m not able to be as through as i would like. I'm afraid of spending that much money trying and overlooking some small hole where the sound will still be able to communicate to an ajoining room and have it leak like a hole in a boat.

Pete

Diffusors ... different animal. You can get a diffusor (Perf-Sorber from Questai.com) which is 2"; but, beyond that most diffusors need to be on the order of 4" deep to be worth anything.