# Diffusion or absorption?



## F1 fan (Jul 6, 2006)

For dedicated 2 ch. set up which might be preferable for the side wall first reflection points ?The speakers are symetrically placed and about 27" from the side walls.The speakers are monopoles but with wide dispersion and smooth off axis response.


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## GranteedEV (Aug 8, 2010)

Diffusion panels at the first and second reflection points.

Broadband Absorption is necessary if the off axis response of the speakers is poor IE B&W 802d. If your off axis response is smooth then reflections are desired according to Toole's research among others.

It's all about balance at the end of the day though. You need to measure your in-room CSD to really get a feel for what is necessary and at which frequencies.

You do want bass traps but preferably ones that don't attenuate much above 400hz or so


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## bpape (Sep 14, 2006)

Either can work depending on overall room acoustics and your preference.


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## F1 fan (Jul 6, 2006)

Thanks Gents.If I choose the diffusion route would one that's effective only in the upper midrange /lower treble be worthwhile?example.(click calculate.)
http://www.mh-audio.nl/diffusor2.asp#calcul
sOr should I look to a larger one that spans the upper bass and midband?


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## bpape (Sep 14, 2006)

Most QRD's are going to be that way. Remember that you'll also (if done right) go down to 1/2 of the low end with 'scattering' It's not true, smooth diffusion down that low but it does scatter.


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## Johnlee2002 (Jun 14, 2011)

Hi,

My take is that if the room is small, please use absorption to damp all 1st reflection points (spk rear wall, ceiling, side walls and also the listening rear walls).

Diffusion, in my opinion and experience, is useful when u have space in your room so that the diffusion panel can help create a more spatial image of the music in the listening room.


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