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Discussion Starter #1
I am looking for a recommendation regarding ceiling acoustical treatment. I have inceiling speakers and I hear reflections or some echoes off the ceiling near the center channel. I know inceiling speakers are less then ideal and I am going to replace them in the future but is there a preferred ceiling treatment that can address this issue now.

Background

Home theater is 25 x 16 x 8
floor is wall to wall broadloom
OC 703 screen wall, back wall and 1st reflection points on parallel walls
Mirage omni 6 inceiling speakers 7.2 system
Front row of seats are 14 from screen
 

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Are all the speakers in ceiling or just the surrounds? Not sure how you're getting an echo off the ceiling from in-ceiling speakers and only have it be the center?

Color me confused.. :huh:

Bryan
 

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Discussion Starter #3
Hey Bryan

The fronts and rear speakers on in the ceiling. The side speakers are on the wall. I can be watching a scene from a movie and during dialogue it sounds like the character is talking in a tunnel. This is more audible at higher freqencies (female characters mostly). Assuming this is a reflection off the ceiling would some absorptive panels be helpful positioned towards the center channel?

I hope this helps

Dwight
 

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Sounds more to me like a lack of absorbtion in general. I doubt if something on the ceiling is going to be the best bet. I could be wrong. It certainly won't hurt anything to put a panel directly forward of the center channel - though if that is the issue, I'd do it for all 3 speakers up front.

Bryan
 

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Discussion Starter #5
Yeah I also thought I needed more absorption but not sure what else to treat. This is what I have treated todate:

Screen wall - 3 1/2 inch recycled cotton panels covers entire screen wall. I did not build separate bass traps as they form part of the wall build out.
Rear wall- - 6 inch recycled cottom panels covers entire rear wall. Same construction as screen wall.
Side walls - 1 inch oc703 covers first reflection points
Floor - Broadloom
Ceiling - not treated
Door - located at rear of room not treated


There are also parallel walls at the rear of room behind 2nd row of seats not treated (but not reflection points)

Let me know if you think I need more treatment. If not ,then I will treat the ceiling as you suggested. What product do you suggest for the ceiling?

Thanks
 
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Absorption? Oh, yes, the universal antidote.

While I hate to suggest this, the source of the problem is most likely the location of front and rear speakers in the ceiling.

There is a good reason why ceiling speakers are typically used in zoned speaker systems - and for the same reason why they are not optimal for general listening rooms.

You have essentially a high Q coverage area directly beneath the speakers, but no where else - the same quality that makes a zones system so effective.
Your primary reflection will be off the floor - of which absorption thick enough to effectively control the mid and high frequency energy is impractical - unless you enjoy a 'bouncy house'.

I would seriously suggest, if the ceiling speakers cannot be easily relocated to the walls, that an angled enclosure be properly designed, utilizing current modeling procedures, and employed which angle the speakers such that the primary listening positions are on axis with the speakers. This will not only minimize secondary reflections, but it will increase the localization and reduce the 'tunnel' effect.

What you are experiencing is a localization effect from one of the ceiling speakers similar to what Henry describes in the Precedence Effect, with the side speakers serving as a principle source depending upon the seating position due to their more universal on-axis orientation throughout the room.

Once you have addressed this, THEN you can measure the room and determine the arrival times and intensity of the relative signals and specular reflections with an ETC measurement (in addition to measuring the real room modes with a cumulative spectral decay) and then proceeding to surgically apply absorption to tune the Initial Signal Delay Gap and diffusion to optimize the later arriving semi-reverberant diffuse field as appropriate.
 

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Discussion Starter #7
Hi Mas. Thanks for your reply. I agree with your assessment and have decided to replace the in ceiling speakers with some good inwalls or floor standing speakers as part of my HT upgrade later in the year. I will also forgo adding more absorption at this time until I make the speaker change and do more analysis to fine tune the environment.

Cheers
Dwight
 

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... have decided to replace the in ceiling speakers with some good inwalls or floor standing speakers as part of my HT upgrade later in the year. ...
Good!!! :T

But, just go ahead and get Bookshelf or Floorstanders instaed of In-walls ... just my opinion :hide:

Keep your eyes open for any good deal ... there some floating around (i mean, compared to original prices) :bigsmile:
 

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I would agree that doing anything other than in-ceilings is a good idea. Getting freestanding speakers can definitely offer a lot of options to help tune things. You may well find that the tunnel effect could partially have been poor off axis speaker response. The proof will come once the speakers have been changed.

Bryan
 
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