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Acoustic panels hanging from the ceiling?

post #1 of 22
3/27/08 at 10:35am
Thread Starter 
I have been to a few home theater demonstration rooms that had what appeared to be acoustic panels hanging from the ceiling at an angle. What is the purpose of these? Should they be tilted towards the screen or away? Why don't they just attach them flat to the ceiling?
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post #2 of 22
3/27/08 at 10:54am
Quote:
Originally Posted by InPhase View Post

... acoustic panels hanging from the ceiling at an angle. What is the purpose of these?

To absorb early / first reflections. More here:

http://www.realtraps.com/rfz.htm

Quote:


Why don't they just attach them flat to the ceiling?

When an absorber panel is mounted a few inches away from a surface it works to a lower frequency. The panel also behaves as if it is larger because sound striking the ceiling or wall near the panel can get into the rear and be absorbed. This assumes the panel is designed with an absorbent rear surface.

--Ethan
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post #3 of 22
3/27/08 at 1:59pm
Thread Starter 
I understand the advantages of leaving room between the absorber panel and the surface. It is the angle that perplexes me. They were hanging at angle of around 25-45 degrees I believe. I don't see many here designing their home theaters with panels hanging at an angle above the listening position. Is this an old trick for less effective absorbers?
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post #4 of 22
3/27/08 at 4:13pm
Quote:
Originally Posted by InPhase View Post

I understand the advantages of leaving room between the absorber panel and the surface. It is the angle that perplexes me. They were hanging at angle of around 25-45 degrees I believe. I don't see many here designing their home theaters with panels hanging at an angle above the listening position. Is this an old trick for less effective absorbers?

Angles make the reflections (from walls or those not absorbed by panels) rebound at a greater or less than 90 degree angle. That way the reflection bounces around the room at odd angles and dissipates.

90 degree angles cause it to bounce back and forth repeatedly between two walls or from ceiling to floor. This allows it to build upon itself effectively sounding louder as the reflection passes the listener repeatedly in the same plane.
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post #5 of 22
3/28/08 at 4:25am
Quote:
Originally Posted by InPhase View Post

I have been to a few home theater demonstration rooms that had what appeared to be acoustic panels hanging from the ceiling at an angle. What is the purpose of these?

It depends on the type of panels. If they are fiberglass, then they will absorb sound on both sides. If you have the ceiling room (cathedral ceiing), these can make a very effective treatment option. I recently designed a very large home theater with 15 4x8 foot acoustical clouds and baffles hanging from the ceiling!

Hanging, angled reflective panels redirect sound, and improve diffusion. You find them in laboratory reverberation rooms, which need to be extremely "live" but also to have very diffuse sound fields.

Regards,
Terry
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post #6 of 22
3/28/08 at 9:09am
Thread Starter 
In a home theater, wouldn't you want to make the ceiling virtually disappear by using absorber panels instead of creating reverberation? Wouldn't this be more similar to recreating the very tall ceilings in real cinemas?

Terry, what is an acoustical cloud/baffle? That must be a huge room! Do you have any pictures of a theater with the panels hanging from the ceiling? I can't seem to find any pics of these.
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post #7 of 22
3/28/08 at 9:21am
Quote:
Originally Posted by InPhase View Post

Terry, what is an acoustical cloud/baffle? That must be a huge room! Do you have any pictures of a theater with the panels hanging from the ceiling? I can't seem to find any pics of these.

Yes, some of my clients have very large home theaters.

I don't know if this is an official definition, but in my experience, a cloud is anything hanging from the ceiling either horizontally or at an angle, while a baffle hangs from the ceiling vertically.

Here is an example of an acoustic cloud:
http://www.allnoisecontrol.com/products/Clouds.cfm

Here are acoustic ceiling baffles:
http://www.enoisecontrol.com/baffles.html

Regards,
Terry
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post #8 of 22
3/28/08 at 11:28am
Quote:
Originally Posted by Terry Montlick View Post

If they are fiberglass, then they will absorb sound on both sides.

Yes, as long the panel is not backed with Masonite or plywood as is sometimes done.

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If you have the ceiling room (cathedral ceiing), these can make a very effective treatment option.

Yes, and I have that in both my home studio and my living room HT (photos below). This works very well to avoid the focusing that can happen under a peak or curve.

--Ethan



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post #9 of 22
3/28/08 at 11:45am
Cute video Ethan
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post #10 of 22
3/29/08 at 8:48am
Quote:
Originally Posted by dknightd View Post

Cute video Ethan

Thanks!
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post #11 of 22
3/17/09 at 10:53am
Has anyone used a drop a simple drop ceiling grid ( 2x2 tiles) in a 10ft by 10ft suspended 2 or 3 inches from an existing finished drywall ceiling? I figure the tiles will help with sound leak to upstairs. How does the metal/plastic in the grids affect sound?
In my head I see this a few inches suspended with maybe a LED rope tucked inside for a soft light effect.
Ideas?
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post #12 of 22
3/17/09 at 11:29am
Super cool, but I was just thinking something simple (and cheap) using a t-bar grid and tiles.
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post #13 of 22
3/17/09 at 11:50am
Quote:
Originally Posted by Terry Montlick View Post

Yes, some of my clients have very large home theaters.

I don't know if this is an official definition, but in my experience, a cloud is anything hanging from the ceiling either horizontally or at an angle, while a baffle hangs from the ceiling vertically.

Here is an example of an acoustic cloud:
http://www.allnoisecontrol.com/products/Clouds.cfm

Here are acoustic ceiling baffles:
http://www.enoisecontrol.com/baffles.html

Regards,
Terry

What about these? They don't look like they fit in either catagory.

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post #14 of 22
3/18/09 at 5:49am
Quote:
Originally Posted by Rutgar View Post

What about these? They don't look like they fit in either catagory.


Clouds. Looks like they may be hard surfaced, in which case they could function as diffusers. Yes, diffusers can consist of just angled hard panels. This type of diffuser is commonly used in lab reverberation rooms.

What absorptive ceiling clouds and baffles have in common is that they treat a volume of air. They effectively create this volume themselves. The result is more available absorption surface than would otherwise exist in your room. Treating ceiling reflections is a bonus. They are great for controlling reverberation in rooms which have limited areas available for treatment.

- Terry
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post #15 of 22
3/18/09 at 6:34am
Quote:
Originally Posted by jschlesi View Post

Has anyone used a drop a simple drop ceiling grid ( 2x2 tiles) in a 10ft by 10ft suspended 2 or 3 inches from an existing finished drywall ceiling?

Yes.

Quote:


I figure the tiles will help with sound leak to upstairs.

Not so much. If you use acoustical tiles, the major effect will be on the room they are in.

If you want to reduce transmission, build a second ceiling on its own frame, that is as isolated as possible from the existing ceilng. Dry wall would be fine.

Quote:


How does the metal/plastic in the grids affect sound?

not so much
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post #16 of 22
3/18/09 at 7:42am
Quote:
Originally Posted by Terry Montlick View Post

Clouds. Looks like they may be hard surfaced, in which case they could function as diffusers. Yes, diffusers can consist of just angled hard panels. This type of diffuser is commonly used in lab reverberation rooms.

What absorptive ceiling clouds and baffles have in common is that they treat a volume of air. They effectively create this volume themselves. The result is more available absorption surface than would otherwise exist in your room. Treating ceiling reflections is a bonus. They are great for controlling reverberation in rooms which have limited areas available for treatment.

- Terry

Thanks Terry. Approximately what range of frequencies do you think this setup addresses?
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post #17 of 22
3/18/09 at 7:55am
Quote:
Originally Posted by Rutgar View Post

Thanks Terry. Approximately what range of frequencies do you think this setup addresses?

Honestly, if those are reflective panels, then that particular setup looks dubious to me. It is common to use such hard ceiling panels angled so as to reflect sound from source to listener for live, unamplified music and speech enhancement in auditoria. It both strengthens the sound and provides a sense of spaciousness. I don't see what good it could be doing in a home-sized room for amplified sound.
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post #18 of 22
3/18/09 at 8:20am
Quote:
Originally Posted by Terry Montlick View Post

Honestly, if those are reflective panels, then that particular setup looks dubious to me. It is common to use such hard ceiling panels angled so as to reflect sound from source to listener for live, unamplified music and speech enhancement in auditoria. It both strengthens the sound and provides a sense of spaciousness. I don't see what good it could be doing in a home-sized room for amplified sound.

Well then, it's not just me! I've always wondered how this configuration is supposed to work, and on what frequencies. The picture doesn't show it, but the speakers are located to the right and the listening position is to the left. Which seems like higher frequencies would go into the 'open' end of the panels, and then reflect up to the ceiling thus bouncing around a bit and losing energy. I have no idea what influence this cavity would have on lower frequencies.
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post #19 of 22
3/18/09 at 10:45am
Quote:
Originally Posted by Terry Montlick View Post

I don't see what good it could be doing in a home-sized room for amplified sound.

Agreed.
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post #20 of 22
3/6/13 at 12:52pm
On this same subject we just built some panels using fiberglass covered in speaker cloth for our church. At this point we will be hanging them on the ceiling to help with a major echo problem we have. Would we be better off hanging them flat on the ceiling or at angles and if at an angle what degree? The plan is to use chain so they can be adjusted if needed and the ceiling is 24 ft high.
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post #21 of 22
3/6/13 at 2:48pm
Hang them parallel to the ceiling, a few inches down. The resulting air gap improves absorption.

--Ethan
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post #22 of 22
3/7/13 at 12:08pm
Thanks Ethan, that is a great help and will make hanging them this weekend much easier smile.gif
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