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ttocs

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Final? Really? I've said that before. But I keep . . . doing things, that drains my wallet, and I enjoy it each time it happens.

I'll let the experts jump in for the acoustic panels. Lots of help here at MLO.
 
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spkrdctr

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Well, a quick easy way to help without doing a professional room analysis is to put commercial sound absorbers on the two side walls. That would be a quick start. But if you are doing it yourself, then you have years of tweaking and fiddling to get to what you think is the best sound. Enjoy the process!
 

JonFo

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My usual advice, especially for an HT setup like yours is to start with absorbing the rear wave of the L/R speaker. Your center (a Focus C18, right?) is already a monopole, so no worries there.

The product I recommend for this application is the RealTraps MiniTrap HF. The HF part is important in this application, as we want high-frequency absorption. I have six of them on my front wall alone. But you can start with just two hung on the front wall, offset 3" from the wall and directly in the line-of-fire from the panel. That means if the speaker is toed-in a bit, the trap will hang slight offset towards the sidewall vs directly behind the speaker.

Next step would be adding another minitrap HF on the sidewall, at the bounce-point of the wear wave. Typically, this winds up being right next to the speaker.

Please post a pic head-on of the front, where both side-walls are visible. If not, one of the left speaker and it's relation to the side wall.

What are the room dimensions?
How far is the main seating from the rear wall?
 

kach22i

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Your front speakers look a bit close to the side walls, making full range (bass traps) absorbers of first reflection points tricky.

Maybe you can slip something like curved diffusers from Acoustic Geometry in there?

My advice is opposite of Jonfo's, do the front wall behind the speakers last, and only if you have to.

Also treating the ceiling first reflection points and back wall behind your head come before front wall considerations - in my opinion.

There is a Martin Logan factory video about treating first reflections points, you should watch it before buying anything.
 

JonFo

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treating the ceiling first reflection points
George, mind explaining how a 4' line-array has any dispersion that hits the ceiling?

One of the benefits of LA topology is controlled vertical dispersion.

I do have an absorber right above each Monolith, but that's to deal with lower-frequencies and the floor bounce from the dynamic woofer.
 

kach22i

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George, mind explaining how a 4' line-array has any dispersion that hits the ceiling?

One of the benefits of LA topology is controlled vertical dispersion.

I do have an absorber right above each Monolith, but that's to deal with lower-frequencies and the floor bounce from the dynamic woofer.
Theory & Practice is kind of like Concept Vs Results in that they may not always match up.

In theory a pure line source isn't going radiate up or down, but treat the floor and ceiling of a M/L hybrid and trust your ears.

My ears hear a difference, and you might even be able to measure a difference if you had the right equipment.

Please read post #10 by Duke regarding other dispersion claims.

 

JonFo

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Please read post #10 by Duke regarding other dispersion claims.
Thanks, but that post is exclusively regarding the horizontal dispersion pattern.

In theory a pure line source isn't going radiate up or down, but treat the floor and ceiling of a M/L hybrid and trust your ears.
Been measuring (and listening) to ELSs for over 27 years, and the radiation pattern follows theory. They have next to no direct dispersion in the vertical plane outside the dimensions of the panel, which is one reason the older Gen1 panels have a slight advantage with their taller proportions.

That said, that only applies in an anechoic chamber, in real life there are objects in the room that disperse the sound in many directions. And might include the ceiling, if you have a coffee table between you and the speakers, for instance.
The other is the issue is driven by raked panels, anything other than perpendicular panels is a challenge as if they are angled back by 5 degrees, then the rear wave is ricocheting off the back wall, then the floor and up towards the ceiling.
The front wave is now going to bounce off the ceiling at some point (likely just ahead or behind the listener (depends on distance and height of the ceiling) and then off the back wall.

This mess of reflected energy is why I advocate strongly for management of the rear wave as priority #1, as it is massively destructive to a clear sound field.
Is it possibly 'nice' in the sense that to provides ambiance and 'breadth' to certain recordings, maybe. But accurate, it is not.
 
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