Ceilings: absorption vs diffusers?

[jostenmeat]

I've definitely been leaning towards using some panels on the ceiling, but am now musing over the idea of diffusers. I see that at least a couple of folks think they are a good application for rooms with slap echo, which I have a bit of.

Why do these tend to be more often used on ceilings than on sidewalls, etc? Perhaps this is not true, but that's my preliminary impression.

Can anyone explain why diffusion could be a better application than absorptive panels for any particular situation?

I never considered them for my stereo, because people seemed to have pretty bad luck with them when using electrostats. Why, I don't know. Perhaps too many reflections with a dipole to not focus on absorption.

Do people have places to recommend to find some? I did see a couple of examples of DIY around, balsa and other woods. I'd like to keep it rather whitish to match the ceiling.

Thanks for any insight, once again.

 

[Glenn Kuras]

This is going to be a general statement as no 2 rooms are the same, but absorption is best for the ceiling and side ways in the early reflection points. Diffusion works very well in the back of the room either on ceiling and or side/back walls.

Glenn

 

[Savant]

meat,

It depends on how high your ceiling is. Low ceilings (< ~8 feet) will not benefit from diffusion as much as high ceilings (> ~8 feet). Having written that, I have implemented diffusion on ceilings lower than 8 feet with some success. As Glenn said, it's dependent on the room and on what you want it to sound like when you're finished treating it. Diffusers will give a more "live" sound to the room. Absorbers will deaden it. IMO, for a home theater, the former (diffusion) is more appropriate for ceilings, in general. But that's an opinion and not a rule.

 

[jostenmeat]

Thanks so much guys. I do very much appreciate it. My ceilings are 7'11". And since I have a back row, with a pretty tall riser, I think I will stick with the original idea of absorption.

So, more of a live sound, eh? Do you guys know why a person or two thinks that diffusion might be more effective with slap echo? Is that just a mis-conception?

 

[Glenn Kuras]

Not sure but both will help with slap echo. Diffusion will well ah diffuse it and absorption will well ah ah ah absorb it. The thing about diffusion is it needs space (time) to work properly. Versus absorption you can be VERY close to it and it still works.

Glenn

 

[jostenmeat]

Haha, funny post , and a salient explanation about space/time as its pretty pertinent in my situation.

Thank you Glenn.

 

[majorloser]

From my own personal experiences in my room, the ceiling tends to act like a diaphragm if there is just drywall and open attic above. It's the one flat surface in the room I forgot about when building. You can't hear things in the ajoining room but go outside and you can hear it out of the eaves.

 

[Savant]

The "distance for diffusion" thing Glenn mentioned is generally more valid, IME, for wall-mounted treatments. Due to hearing mechanisms and complexities, ceiling-mounted diffusers tend to be more, ah, forgiving. I will say that 7'11" less riser height is getting to where absorption is the best choice. But for higher ceilings, diffusion should at least be considered. My 1/50th...

 

[jostenmeat]

From my own personal experiences in my room, the ceiling tends to act like a diaphragm if there is just drywall and open attic above. It's the one flat surface in the room I forgot about when building. You can't hear things in the ajoining room but go outside and you can hear it out of the eaves.

Interesting, I was just deciding today that Im going to put in new insulation in the attic. Well, when Im watching a movie, you can definitely sure as heck here it throughout my home!

However, its really only bass waves that I ever get concerned about. There is not a whole lot of distance between the neighbors' homes, but I make sure all doors and windows are closed when cranking the HT. No complaints yet, and I've asked them if they've ever been bothered. They said no last I asked, and I want to keep it that way.

 

[bpape]

If you don't have specific height related issues you're trying to address, either can be effective. Just remember that in addition to the distance thing that's been mentioned, it's going to take a lot more thickness to diffuse all the way down in the vocal range than to absorb it.

Bryan

 

[jostenmeat]

Absorption it is!

Thanks again guys. Its so great to have knowledgable folks at my beck and call, free of charge!

 

[just-some-guy]

ok, so. lets see what you did.

i have flexicore ceilings, and slab sub floor, condo. slap echo was bad, thick carpet helped a lot. i used to have drop ceiling panels on the center of the ceiling. that helped a ton. i took them down years ago, hoping to sell the condo = still here . i mis them.

 

[jostenmeat]

I have done a lot of absorption already. Curtains, 9 panels, rugs on top of carpet. The ceiling is most likely the sore thumb. I haven't done anything about it yet. Since I started this thread, I've implemented Audyssey Multi EQ XT which I really, really dig. So much so, I'm starting to look into it for my stereo rig. I really wish companies made integrateds or stereo receivers with Audyssey. Seriously. Awesome stuff.

For the ceiling I have my eyes on some Real Trap Micro's. They're expensive, but I like the fit and finish, high quality, and easier mounting. I'm still in a holding pattern. FWIW, I may never do it. Who knows. Maybe they'll pop up one day on the classifieds, as that's where I've obtained most of my panels already.