# Placing acoustic panels behind speakers



## Doctor X (Apr 3, 2007)

Hi guys,

I've seen guys place treatment on the rear wall, side walls and ceiling. But I've also noticed placement of panels behind the main speakers in a dedicated 2-channel listening room. 

What purpose would placing the panels behind the speakers serve? 

I have a small room and I have acoustic panels at the early reflection points on the rear wall, ceiling and (no side-walls to treat) I have a heavy rug on the floor. However my main speakers are very close to the wall so I placed acoustic panels behind them.

Now, I was recommended to do to this when I bought my acoustic treatment. So my question is, what exactly is happening if I place the treatment behind the main speakers and would it serve any real purpose? 

I can't test the difference that removing the front panels would make since they are bolted on to brackets, so I'm just asking out of curiosity.


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## bpape (Sep 14, 2006)

The panels behind/slightly inside/between the speakers are there to address what is called SBIR. That is the interaction of the direct and reflected waves (bass radiates spherically) that will arrive at you at a different point in their phase causing either peaks or dips in response. Minimizing the intensity of the reflected waves also then minimizes the response variations since they cannot combine or cancel as severely.


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