How far should speakers be placed away from walls to eliminate smearing from early reflections?

caesar

Active Member
May 31, 2010
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#1
What is the ideal distance for speakers to be placed away from walls to eliminate the smearing effect of early reflections?

In a perfect scenario, is the middle of the room the best place?

Thank you
 
#2
It is completely room dependent. See, for example, Steve Williams room where his big Wilsons are very close to the sidewalls what most would argue is a no-no, but properly treated room problem solved!
 

DaveC

[Industry Expert]
Nov 16, 2014
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#3
It depends on the dispersion pattern of the speaker, size of room and personal preference. My preference would be a somewhat nearfield setup with the speakers a good distance from any of the walls and a controlled, even and smooth dispersion pattern.
 

DaveC

[Industry Expert]
Nov 16, 2014
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#4
It is completely room dependent. See, for example, Steve Williams room where his big Wilsons are very close to the sidewalls what most would argue is a no-no, but properly treated room problem solved!

I'd go with problem somewhat mitigated... ;)
 

steve williams

Site Founder,Co- Owner, Adminisrator
#5
I'd go with problem somewhat mitigated... ;)
Solved is really a better word in my room. There are no side reflections. Having said that I agree that in a perfect world with a large room these issues are easily controlled.
 

caesar

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May 31, 2010
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#6
It is completely room dependent. See, for example, Steve Williams room where his big Wilsons are very close to the sidewalls what most would argue is a no-no, but properly treated room problem solved!
Obviously I haven't heard his setup, but doesn't killing that stuff off make the room sound dead?
 

steve williams

Site Founder,Co- Owner, Adminisrator
#7
Obviously I haven't heard his setup, but doesn't killing that stuff off make the room sound dead?
Not at all

My RT 60 measures perfect
 

steve williams

Site Founder,Co- Owner, Adminisrator
#8
Caesar

Before you start making assertions about a dead room I suggest you listen and then comment.

The same acoustician who did my room did Bobs. Two different designs with two excellent results
 

caesar

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May 31, 2010
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#9
Caesar

Before you start making assertions about a dead room I suggest you listen and then comment.

The same acoustician who did my room did Bobs. Two different designs with two excellent results
Steve, I am not making any assertion. As I mentioned above, I have not heard every single implementation. But so many guys recommend absorption- which in my experience kills the fun.
 

DaveC

[Industry Expert]
Nov 16, 2014
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#11
Solved is really a better word in my room. There are no side reflections. Having said that I agree that in a perfect world with a large room these issues are easily controlled.
That's good, it does depend on personal preference. Personally, I'm happy without reflections off the side walls and also choose speakers with narrower dispersion so it's not an issue either.... others might see that as a huge compromise. Of course Harman's research says sidewall reflections are desirable and give you a sense of spaciousness. IMO it's a result of 1. Acclimation 2. A test system without sufficient resolution to reproduce most of the spatial cues in the recordings. But since Amir isn't here I thought it would be good to point that out. ;)
 

caesar

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May 31, 2010
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#12
It depends on the dispersion pattern of the speaker, size of room and personal preference. My preference would be a somewhat nearfield setup with the speakers a good distance from any of the walls and a controlled, even and smooth dispersion pattern.
Hi DaveC,

Don't you still get that smearing from reflections even if you choose to sit near-field? What do you recommend to get a smooth dispersion pattern?
 

DaveC

[Industry Expert]
Nov 16, 2014
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#13
Obviously I haven't heard his setup, but doesn't killing that stuff off make the room sound dead?
Not for me. Others will disagree.

I think sidewall reflections are often preferred due to acclimation (that's what we're used to) and the fact many systems can't reproduce many spatial cues in the recording so room reflections become the substituted spatial cues. But it makes it sound like all the music is being played in your room rather than hearing the acoustics of the various venues the recordings were made at.
 
May 30, 2010
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#14
Anyways, is there an ideal distance away from the walls for one not having to deal with this problem?
No. Stereo needs some proper reflection in walls and there are so many variables in speakers, rooms, walls (!) and preferences that it is not possible to have a one figure recipe.
 

caesar

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May 31, 2010
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#15
Solved is really a better word in my room. There are no side reflections. Having said that I agree that in a perfect world with a large room these issues are easily controlled.
Steve, can you please share how your problem was solved, or is something proprietary?

One way people solve this problem is using SMT wing products...in effect they become the "new wall"...yet even they need to be a certain distance from the speaker...
 

DaveC

[Industry Expert]
Nov 16, 2014
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#16
Hi DaveC,

Don't you still get that smearing from reflections even if you choose to sit near-field? What do you recommend to get a smooth dispersion pattern?
Nearfield gets you more direct sound vs reflected sound and also increases the time delay between direct and reflected sound, both are good things!

Dispersion pattern is dependent on the speaker only, a polar plot of the speaker will tell you most things about how the speaker will sound that we can measure. While overall dispersion width or angle is subject to personal preference a smoothly falling off-axis response is universally good.
 

JackD201

[WBF Founding Member]
Apr 21, 2010
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#17
Look up the Haas effect. There is a window where early reflections are BAD because in this short time range the brain mixes the direct and reflected sound. Outside of that the brain can distinguish direct from reflected and this is what is subject to preference. That said there are basically three ways to deal with the problem. Absorb, Diffuse or redirect with reflection. You just need to know the distance of travel of the direct sound and the distance of travel of the reflection to determine if that filtering your hearing is caused by your placement or not. You want their arrival times to be outside of the problematic time window. With speed of sound as constant simply compute if the distance from driver to wall to listening position will arrive later than the direct sound by at least around 100ms for music programme. That should put you out of the worst scenario as far as the first lateral reflections go. Of course now you have to deal with reverberation.
 

caesar

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May 31, 2010
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#18
Look up the Haas effect. There is a window where early reflections are BAD because in this short time range the brain mixes the direct and reflected sound. Outside of that the brain can distinguish direct from reflected and this is what is subject to preference. That said there are basically three ways to deal with the problem. Absorb, Diffuse or redirect with reflection. You just need to know the distance of travel of the direct sound and the distance of travel of the reflection to determine if that filtering your hearing is caused by your placement or not. You want their arrival times to be outside of the problematic time window. With speed of sound as constant simply compute if the distance from driver to wall to listening position will arrive later than the direct sound by at least around 100ms for music programme. That should put you out of the worst scenario as far as the first lateral reflections go. Of course now you have to deal with reverberation.
Thank you, Jack! I will read up on that.

Out of the 3 approaches you mention - Absorb, Diffuse, or Redirect with reflection, do you happen to know if the SMT wing products are in the Redirect camp?
 

caesar

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May 31, 2010
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#19
No. Stereo needs some proper reflection in walls and there are so many variables in speakers, rooms, walls (!) and preferences that it is not possible to have a one figure recipe.
Hi Microstrip,

Thanks. Can you please elaborate a bit on "some proper reflection" vs. smearing from too much reflection?
 

DaveC

[Industry Expert]
Nov 16, 2014
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#20
Look up the Haas effect. There is a window where early reflections are BAD because in this short time range the brain mixes the direct and reflected sound. Outside of that the brain can distinguish direct from reflected and this is what is subject to preference. That said there are basically three ways to deal with the problem. Absorb, Diffuse or redirect with reflection. You just need to know the distance of travel of the direct sound and the distance of travel of the reflection to determine if that filtering your hearing is caused by your placement or not. You want their arrival times to be outside of the problematic time window. With speed of sound as constant simply compute if the distance from driver to wall to listening position will arrive later than the direct sound by at least around 100ms for music programme. That should put you out of the worst scenario as far as the first lateral reflections go. Of course now you have to deal with reverberation.


For small rooms 100 ms isn't practical as that takes about 33 meters. General rule of thumb is ~4 meters so speakers should ideally be 2 meters or more from sources of reflections.