# Display case effect on reflections?



## Drudge (Sep 1, 2008)

I've put 2 acrylic box display cases,one smaller than the other for 2 of my movie statues behind me on top of an armoire.The smaller case measures 18"Hx10"Dx10"W and the larger 17"Hx14"Dx14"W.The top of the armoire is 4" inches above seated ear height and the face of it is 4' feet behind me against the rear wall.

If I position the cases so that they face like diamonds with the corners straight forward instead of square with the flat sides forward will the cases help break up the reflections that hit them or will this arrangement make the reflections more complex and problematic?


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## bpape (Sep 14, 2006)

It will help deflect reflections from maybe 400Hz or so up. Anything below that will go right around them. Also, you're reflecting everything in 1 direction or the other - not really scattering anything.

Bryan


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## Drudge (Sep 1, 2008)

So,the high frequency reflections will be directed away from the listening position and not be detrimental to the overall sound?


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## bpape (Sep 14, 2006)

Not really. The'll be directed to the side walls and then come back toward the listener - just farther out of time.

Bryan


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## Drudge (Sep 1, 2008)

Oh,so the reflections will just be delayed and come from another direction.I have curtains on the sidewalls that lead up to the first reflection panels for the left and right mains,will that bring the redirected reflections from the cases to the sidewalls to an acceptable level within the first 20ms range?

I was hoping that angling the cases would redirect or break up the the reflections so they would lessen or not adversely affect my rear wall reflection levels.


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## bpape (Sep 14, 2006)

Well, personally, I prefer to leave the rear wall more lively in the upper mids and highs so as not to kill the surround field. I prefer to hit the rear wall with treatments that will address bass anomolies and nulls off of the back wall and leave the highs alone.

Bryan


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## Drudge (Sep 1, 2008)

I was always under the impression that rear wall reflections were meant to be treated in the same way as the sidewall reflections so they would be reduced at the listening position so they wouldn't smear the sound and stay at an acceptable level within the first 15ms.

I figured since the display cases would act like a glass window behind me with them orientated with the flat sides out(which by the way I do have and is covered by a black out curtain) and that it would cause reflection issues.I thought maybe with them facing the other way it would help keep that to a minimum.


Would it just be better to leave them with the flat sides out as you say that you prefer the rear to be a little livelier in the high end?


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## bpape (Sep 14, 2006)

What is your distance from your ears to the surface behind you? You may already be 15ms away from them. Figure the path both ways. General rule of thumb is 1' per 1ms

Bryan


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## Drudge (Sep 1, 2008)

Well,it's 4' to the front of the armoire,so about 8ms.


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## bpape (Sep 14, 2006)

You can try it but as I said, it's not going to do much of anything for dialog down.

Bryan


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## Drudge (Sep 1, 2008)

As long as the cases don't negatively affect the sound then that's all I'm really concerned about.I know they are not going to add any real benefit.


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