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Speakers against front wall - can this be settled?

Speakers within 1m of front wall

  • I tried this and had imaging issues, WITH front wall acoustic treatment

    Votes: 3 7.0%
  • I tried this and had imaging issues, without front wall acoustic treatment

    Votes: 9 20.9%
  • I tried this and had midrange tone issues, WITH front wall acoustic treatment

    Votes: 0 0.0%
  • I tried this and had midrange tone issues, without front wall acoustic treatment

    Votes: 2 4.7%
  • I tried this and had other issues (other than too much bass)

    Votes: 2 4.7%
  • I can't wait to try this

    Votes: 2 4.7%
  • It's great!

    Votes: 25 58.1%

  • Total voters
    43

Frgirard

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Kef falls very low or kef does not want to offend his customers who throw the speakers at random in a room.

There are not subject: the speaker must be against the front wall and of course all is measurable.
 

KMO

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Yeah, that's quite something. That's the Reference series manual, right? I guess they reckon Reference owners have that sort of room.

For the plebs, R series says "0.5m (20") MIN" to side and "225mm (9") MIN" to back.

LS50 Meta is recommended to be ">1000mm" to side, ">500mm" to back.
 

markus

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Hardly. That might be right for studio monitors but for home hifi these companies are in the business of selling speakers that customers expect to sound right connected to anything from their vintage receiver to a minimalist integrated amp to modern room compensating systems.

Unless DSP is built into the speaker, manufacturers are giving their guidance based on the lowest common denominator.
Any speaker can be improved with EQ because no room is like the other. The messages doesn't seem to have reached the outskirts of audio land :)
 

bo_knows

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Yeah, that's quite something. That's the Reference series manual, right? I guess they reckon Reference owners have that sort of room.

For the plebs, R series says "0.5m (20") MIN" to side and "225mm (9") MIN" to back.

LS50 Meta is recommended to be ">1000mm" to side, ">500mm" to back.
And this is what we get from Revel:

1641239247572.png
 

dshreter

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Any speaker can be improved with EQ because no room is like the other. The messages doesn't seem to have reached the outskirts of audio land :)
That point I completely agree with. My dispute was that speaker manufacturers expect their speakers to be used with EQ, when I believe in most cases they’re not
 

Thomas_A

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My DIY speakers have the mid-woofer about 30 cm from a wall with a damping panel behind. So first cancelation should occur around 285 Hz or so. Below measurement with 35 ms window about 1-1,5 meter from the monitors (excl subwoofer). Not sure how to window such a measurement to reveal SBIR.

speaker response.png

And another one with about 13 ms window:

speaker respnse 13 ms.png
 
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73hadd

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And this is what we get from Revel:

View attachment 176482


The third bullet of that section of the document is:

"Move the loudspeakers closer to the corners or walls of the
listening room to increase bass response."

And then goes on to recommend absorbing first reflection points, among other things. I only mention it because it does not say "keep them away from the walls at all costs."
 

FrantzM

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Hi
It is my opinion, that there are placement of speakers, that provides in a given room in a given configuration, that is with furnishing, eventual treatment, etc best approximation of an audio event. All this verbiage to call it, a "soundstage" or perhaps "imaging", concepts familiar to most audiophiles, but that remains nonetheless difficult to properly measure or even define...
My personal, anecdotic experience and I am sure, that of many, is that placing most speakers at the front walls and close to other boundaries doesn't seem to provide that sense of soundstage , and let's be blunt of "realism"... Some speakers may be designed for that , most aren't. On top of that, placing speakers at or close to boaundaries tend to give rise to various issues, some in the bass can be tamed by EQ/DSp, in the rest of the spectrum, it tends to become more difficult to deal witht hese by EQ/DSP...

This has lead me at this point in my audiophile journey to see subwoofers as mandatory. Main Speakers, (mains) are placed for best soundstage and imaging (that is : at a certain distance of boundaries) and subwoofers, plural :), cover the bottom, placed at the boundaries (corners, walls...) . SBIR can then be dealt with EQ/DSP, in concert with the subwoofers. Strategies can vary. Some would cross the mains at 80 Hz, limiting the amount of bass (and most often of THD ) the mains would produce as well as allowing them some of headroom. Others run their mains full range, which allows a potentially smoother Low frequency response by multiplying the number of LF radiators ( 2 mains + the subs) but at the expense of increase of THD in the bass... Something we are not too sensitive to, by the way. This is becoming my preferred strategy when the mains are capable.

My conclusion: No. Unless the speakers are designed for it, say the Dutch and Dutch 8C. Else.. repeating: No.

Peace.
 

Webninja

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This is a good topic, as I’ve been moving my front speakers around and measuring. I was at about 2 ft side and back, which seems to not be optimal from what I just learned.

How accurate is the room simulator in REW?

Much easier to move speakers around virtually
 

Berlin

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When placing loudspeakers close to the front wall I usually use also broadband absorbers in between to improve the imaging.
Don't the absorbers have to be very thick to absorb low frequencies significantly?
 

markus

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By placing a speaker close the the front wall you're changing the temporal and spatial reflection pattern within the room. That reflection pattern can reduce or add spaciousness to the presentation which people like. The problem is that you add the same amount of playback room spaciousness to each and every recording.
My approach is different: remove the playback room acoustics from the presentation as much as possible and add spaciousness using additional speakers, aka multichannel. That way either the recording or the listener can control the presentation in a predictable way.
 
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markus

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Don't the absorbers have to be very thick to absorb low frequencies significantly?
Porous absorbers need to be placed where air velocity is high so if you're close to the source (or the listener) it's easier to "catch" energy. I'm not aware that much research has been done in that area but think it could result in highly effective solutions which aren't necessarily obtrusive. Or maybe the opposite is the case and some kind of absorptive "bun" around the speaker would be desirable?
 
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73hadd

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But that’s not due to improved acoustics, just the mind playing tricks. If there are valid reasons speakers should be pulled out from the wall I would be interested to learn more though.

Yes, this is the question I would like answered, if there are valid (measureable) reasons speakers should be away from the front wall. A greater side wall distance is easier for me to understand, because it can reduce short delay reflections of forward firing sound. (blurring image.)

For the experience of affected midrange when close to the front wall, I would like to know what is to blame, and what the mitigations might be.

I appreciate all of the contributions so far and here are my conclusions:

1. Nearest to front wall <1M:
Pro:
a. Reduce SBIR.
b. Uses less room space.

Con:
a. Too much bass (unless speakers were specifically designed to rely on boundary.)
b. Possible issue with "bass timing or imaging" due to a short delay between direct and reflected sound.
-Saying this with certainty means we need to know if we are sensitive to timing/blurring at frequencies below 250hz
c. Possible issue with "midrange" above 250hz. Needs more definition/measurement/evidence, as above 250hz we expect forward firing sound to not be affected by front wall reflection?
Mitigation:
-
EQ or crossover settings to reduce bass
-4" Absorbers on the front wall can provide NRC 1.0 somewhere between 250-315hz, which would help with some midrange reflections.
-No solution for bass timing issues?

2. Placing speakers in the "AVOID zone 1M-2.2M"
Pro:
"Improved imaging." Needs more definition/measurement/evidence.

Con:
a. Deep SBIR notches between 40-80hz
b. Uses more room space

Mitigation:
-Subwoofers.
-Really thick absorbers on front wall.
-Deep SBIR notches cannot be fixed with EQ, as Genelec says increasing output also increases cancellation.


3. Placing speakers 2.2M+ away from front wall
Pro:

Eliminate SBIR for all but 30hz notch?
Con:
Room space.

I should point out that Genelec does mention 2.2M+ as an option, it's not that they only recommend close to the front wall.




Back to the Midrange clarity conversation:
When placed close the the front wall, if the issue with midrange clarity is short delay reflections from the front wall adding to the direct sound:
-What frequency range is most critical? Low midrange 250-500hz? Assuming that we are not getting rearward sound above a certain frequency.
-What increase in ms delay is required to "improve clarity." It seems 1-30ms can be perceived as one event? This might be harder to define (but worth doing.)
-What physical distance is required to achieve the desired ms delay? (1ms=1.1ft, 3ms=1m)
-We would need to know answers to the two above, in order to prove whether or not the "about 1M improves clarity" is doing what we think it is doing, and use the distance more accurately to address specific issues.
-(I am leaning toward this midrange issue again being more about too much bass or SBIR than reflections)





Thanks to @thewas for bringing my attention to this concept in another thread!
 

thewas

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Don't the absorbers have to be very thick to absorb low frequencies significantly?
The low frequencies are not really relevant to imaging. Also by placing the loudspeakers close to the front wall you move the corresponding SBIR higher in frequency where wider baffle loudpeakers start already some beaming and usual absorbers also start being active.
 
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73hadd

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This is a good topic, as I’ve been moving my front speakers around and measuring. I was at about 2 ft side and back, which seems to not be optimal from what I just learned.

How accurate is the room simulator in REW?

Much easier to move speakers around virtually

I can respond to one of your comments about "2ft side and back," as I have heard from multiple places that you will want those two distances to vary from one another, to avoid duplicate wave/reflection from side wall and back(behind speakers) wall.
 
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Hipper

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Positioning of full range speakers (that is, not using subwoofers) and, equally importantly, positioning your ears (listening chair), is a compromise between controlling bass and dealing with wall reflections and imaging. Getting smooth, even bass has to be the priority as once this is controlled the mids and highs are revealed more clearly.

There can be no hard and fast rules with speakers generally as they have differences in the way they produce sound. There can also be no hard a fast rules with rooms as they and their contents are different. Therefore if you want to do the job properly you have to find out for yourself where your speakers and ears should go in your room for the best compromise. You could use guidance like that from Genelec as a starting point but then find the best solution for your situation.

So the answer to the general question 'speakers against the front walls - can this be settled' is 'no'!
 
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