Speaker and internal wall layout options - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 5 Old 02-26-2020, 07:39 AM - Thread Starter
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Speaker and internal wall layout options

Is there any benefit in doing any of these as per attached ?


Currently running Layout 1 but there is a lot of echo. The room is basically untreated and sounds good apart from the ringing echo. I know I can treat the room to get rid of this but I thought non-parallel walls will do the same and then Layout 2 will allow me to use the framed angled wall as a LLT sub enclosure (having trouble fitting subs in at the front) or fill with insulation for absorption, and Layout 3 will eliminate first reflections (although not sure I want that since my existing first reflections are giving me an excellent soundstage).


Thoughts ?
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post #2 of 5 Old 02-26-2020, 08:57 AM
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Why foil backed fluffy? How do you fill a frame?
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post #3 of 5 Old 02-26-2020, 04:27 PM - Thread Starter
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Quote:
Originally Posted by BIGmouthinDC View Post
Why foil backed fluffy? How do you fill a frame?

I read somewhere that the foil backing makes it more effective as an absorption panel. Something to do with the high frequencies get reflected back through the fluffy but the lower ones go through and don't get reflected until they hit the wall 4" further behind the foil. Its built exactly as you would an absorption panel. (with a cutout in the fluffy for the centre speaker).


I mentioned this because obviously it will affect the sound from the L&R speakers differently to either the existing brick sidewall or the potential angled drywalls.


So do you think the angled side walls will of any benefit (they will serve a secondary purpose of eliminating outside light as well) or best just to stick to the usual absorption panels to get rid of the ringing ?
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post #4 of 5 Old 02-26-2020, 08:50 PM
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Quote:
Originally Posted by niterida View Post
I read somewhere that the foil backing makes it more effective as an absorption panel. Something to do with the high frequencies get reflected back through the fluffy but the lower ones go through and don't get reflected until they hit the wall 4" further behind the foil. Its built exactly as you would an absorption panel. (with a cutout in the fluffy for the centre speaker).
I won't say that anyone is right or wrong, but consider this from a physics perspective:
Power density = transmitted power / 4pi times range squared

If you are mounting a panel 4" off of the wall, without the foil backing, the high frequency energy not fully absorbed by the panel will continue to travel through the panel and to the back wall and reflected back through the panel again - exactly as you described for the lower frequencies. The high frequencies will have experienced a free space path loss for 8" (4" to the wall and 4" back to the panel) and then the loss through the panel. So how would having a foil backing, which does not permit that extra free space path loss, make it better for absorption at higher frequencies?

Quote:
Originally Posted by niterida View Post
I know I can treat the room to get rid of this but I thought non-parallel walls will do the same
You are saying you would build out non-parallel walls rather than treat existing walls? Seems like a lot of hard-to-reverse work for what might amount to a disappointment.
If your only problem is high frequency ringing, have you considered treating your ceiling or high corners?
Have you used Room EQ Wizard (REW)? You can measure your room and look at when your ringing occurs and based on that time measurement convert to distance and have a better understanding of which surfaces are causing it and therefore where you need to treat.

Last edited by tookoolkris; 02-26-2020 at 09:07 PM.
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post #5 of 5 Old 02-27-2020, 12:05 AM - Thread Starter
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Quote:
Originally Posted by tookoolkris View Post
I won't say that anyone is right or wrong, but consider this from a physics perspective:
Power density = transmitted power / 4pi times range squared

If you are mounting a panel 4" off of the wall, without the foil backing, the high frequency energy not fully absorbed by the panel will continue to travel through the panel and to the back wall and reflected back through the panel again - exactly as you described for the lower frequencies. The high frequencies will have experienced a free space path loss for 8" (4" to the wall and 4" back to the panel) and then the loss through the panel. So how would having a foil backing, which does not permit that extra free space path loss, make it better for absorption at higher frequencies?
And that means the high frequencies get absorbed too much, by reflecting them earlier the absorption rate should be closer to that of the lower frequencies. Anyway that was my understanding of it when it was explained to me - I think it was Nyall Mellor ( but don't quote me on that ) who suggested it and I believe he knows what he is talking about.



Quote:
Originally Posted by tookoolkris View Post
You are saying you would build out non-parallel walls rather than treat existing walls? Seems like a lot of hard-to-reverse work for what might amount to a disappointment.
If your only problem is high frequency ringing, have you considered treating your ceiling or high corners?
Have you used Room EQ Wizard (REW)? You can measure your room and look at when your ringing occurs and based on that time measurement convert to distance and have a better understanding of which surfaces are causing it and therefore where you need to treat.

As I said the ringing wasn't the only reason I was thinking of doing it. I was also wondering if the splay and the corner mounting would improve (or make worse) the other room responses, or if I could use the area behind as lower frequency absorption than I would get with panels, and possibly better aesthetics (speakers would be pretty much concealed).



Anyway its all a moot point. I changed my speakers and the splayed walls aren't possible any more.


Thanks for the input anyway
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