Author Topic: Help with ceiling  (Read 4838 times)

Offline Carlman

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Help with ceiling
« on: January 04, 2011, 10:40:25 AM »
Can someone identify the acoustic treatment used in this ceiling:


It's from this article: http://www.magazine-audio.com/2007/cd-player-shanling-cd-300/

Rich or someone? had told me about this design and I didn't understand it but now I see it.  I like the idea but I'm not sure how it works.  Any insight about the principle or the effectiveness is appreciated.

-C
I really enjoy listening to music.

Offline rollo

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Re: Help with ceiling
« Reply #1 on: January 04, 2011, 11:11:39 AM »
  It appears to be Knotty pine. One panel looks like a material batton was put over the wood above the speakers. Basically a big diffuser as it looks to me without a close up. What i do not get is why the clg. and floor are of a reflective nature. granted there is a soft carpet before the speakers however a fully carpeted floor would balance the hard clg. surface.
   Bryan will know.

charles
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Offline richidoo

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Re: Help with ceiling
« Reply #2 on: January 04, 2011, 11:23:20 AM »
The slanted panels stop echo from slapping between the floor and ceiling. It is sometimes used on the side walls too. Reflections from midrange on up are pushed rearward for absorbtion by a dead rear wall. Above the reflective angled surface is absorbtion to kill some midrange energy and upper bass echos too. This is a common trick used by Rives, acoustic consultants. Shane is/was a Rives dealer. He can hook you up.  Tell him you want it in piano gloss teakwood. ;)

Looks like the front most panel is soft for more absorbtion. It's still more effective with the tilt than putting it flat on the ceiling.

The disadvantage of any striped treatment is lobing. Midrange tone will vary between seats front to back as phase delays in midrange freqs change abruptly. Curving the panels would reduce that. You will not notice this if your head is not in the zone of reflections from two different panels, or if you're in the front seat ahead of where the lobing effect begins, maybe that's why the front panel is soft? But it's not as good as diffusion which, by dispersing reflections, smooths out phase distortion effects (comb filtering.) The nice thing about the tilted wood panels is lots of coverage for a low price and it will treat to lower mid freqs than standard diffusion methods, if the backwall is absorptive enough. It is a popular treatment because floor and ceiling are typically hard surfaces, even with carpet some midrange echo survives, they are always parallel and largest surfaces in the room when door openings and window treatments are considered. Slap echo is a big source of midrange distortion, and probably the largest distortion component of any system. 8 foot ceiling will make nodes in multiples of 70Hz, muddying bass too.

Offline bpape

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Re: Help with ceiling
« Reply #3 on: January 04, 2011, 11:42:09 AM »
Many times, with angled baffles like that, they're hard on the side that faces the listener but actually open and absorbent in the front area so direct sound is absorbed but reflected sound is pushed back down and minimizes the slap top to bottom. Just a way to not completely kill the ceiling and leave a little life while killing early reflections.

Bryan
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ebag4

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Re: Help with ceiling
« Reply #4 on: January 04, 2011, 12:45:09 PM »
It appears to the be similar to the tweek recommended in the last Morrow Audio newsletter:

http://www.morrowaudio.com/newsletters/issue7.html

Is anyone doing this?  Did you find it improved the sound in your space?

Best,
Ed

Offline Carlman

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Re: Help with ceiling
« Reply #5 on: January 04, 2011, 02:24:10 PM »
I haven't tried it... right now I'm using 2 4' x 8' diffusing/absorbing panels mounted flat to the ceiling.  They do fairly well but I was just thinking of trying some different stuff.. and that slatted ceiling looked kind of cool and possibly effective. 

Rich reminded me of the curved wood idea that Bryan had also suggested... I could probably accomplish a lot with the curved plywood mounted to the ceiling.  I think it could look super cool too.. Black-stained thin plywood curved and run in a brick pattern along the ceiling..

-C
I really enjoy listening to music.

Offline richidoo

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Re: Help with ceiling
« Reply #6 on: January 04, 2011, 03:13:10 PM »
My imagination likes the idea!