Controlled vs wide dispersion in a normal living room environment..

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Placing sofas and speakers in front of a large concave surface like the bay window would be asking for trouble, there is a high risc of focusing all reflection within that concave area to one spot. -Similar to a parabolic antenna, the opposite of a simple polycylindrical diffuser.
 
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What I noticed from the drawings and descriptions shown above is that many of you are dealing with highly constrained conditions that will seriously limit the end result.
Yes. I've largely removed the room from the equation by listening nearfield, I don't think there is any going back for me, and having the speakers and listening position near walls appears to produce largely insurmountable problems.
 
What I noticed from the drawings and descriptions shown above is that many of you are dealing with highly constrained conditions that will seriously limit the end result.

Earl, long time listener first time caller. The dilemma faced by many people listening in small rooms is that the tighter directivity is conventionally accomplished with larger speakers - bigger direct radiators, which are directive through one mechanism, and large waveguides, which are directive due to another.

For fun, I have been designing a dodecahedral omnidirectional speaker using small full-range units. Using 12 units makes up for the low output of these drivers somewhat, and although an omnidirectional high frequency source has some benefits, limiting early reflections is not one of them. The units I am using are 2" BMRs with outstanding wide dispersion into the top octave.

My question is this - do you think there is any merit to narrowing directivity by using sound absorption materials close to the sound source?

To illustrate my suggestion, imagine a 5" sphere with an array of 12 tiny drivers on it (what I am working on.) This source can achieve acceptable sound from 300hz on up. If this array was placed in a 1' diameter cylinder with one open end, lined with acoustic absorbing materials (which are highly effective at these frequencies) do you think the sound could be aimed at the listener? Sort of like an inverse shotgun microphone.

Thanks for your contributions to the hobby over the years, and especially for linking the Griesinger paper on speaker imaging.
 
My question is this - do you think there is any merit to narrowing directivity by using sound absorption materials close to the sound source?

To illustrate my suggestion, imagine a 5" sphere with an array of 12 tiny drivers on it (what I am working on.) This source can achieve acceptable sound from 300hz on up. If this array was placed in a 1' diameter cylinder with one open end, lined with acoustic absorbing materials (which are highly effective at these frequencies) do you think the sound could be aimed at the listener? Sort of like an inverse shotgun microphone.

Thanks for your contributions to the hobby over the years, and especially for linking the Griesinger paper on speaker imaging.

The way that you describe it, I don;t think that it would work, but certainly one could use the shotgun mic approach in reverse to create a high directivity beam over a limited bandwidth. But it would still be big - at least in one dimension.
 
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Yes. I've largely removed the room from the equation by listening nearfield, I don't think there is any going back for me, and having the speakers and listening position near walls appears to produce largely insurmountable problems.

:cool: :)

yes, it is the best way to get accurate reproduction.

A more narrow dispersion speaker can help effectively extend the near field distance .... but, yes, near-field removes the room significantly.


THx-RNMarsh
 
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I used to listen near field before I knew anything about speakers. I think most people will gravitate toward a flat response at listening position regardless of speaker or room. Probably for most people removing the room will sound better. So bigger baffles and more directional speakers. But in a large enough room theres something to be gained from late reflections.

Directional sound is more intense, so as the speaker becomes more directional it should probably have less overall energy. A lot speakers have a baffle step right around cone break up and the combination can sound shouty. So the speaker and room need to work together to a flat overall power response.
 
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