Speakers against front wall - can this be settled?

[markus]

Out of curiosity, can you point me to research on the influence of the distance to front-wall on perception of depth and width (dimensionality of sound-stage)? I am trying to find it but not yet found papers i understand. Over the years i have been playing with loudspeaker positioning, my observations are that close to the front-wall has a detrimental effect on dimensionality. Also when having some significant furniture (cupboard) in between. This invariably improved when using distances of more than a meter or so. (in living rooms i mean)

There is no such research based on controlled (!) listening tests I'm aware of, just a myriad of audiophoolish "facts" ("It's true because I heard it!") filling up tens of thousands (millions?) of posts on social media.

Sight is a powerful bias that can and will override what is heard, e.g. ventriloquism effect. Most of what people hear is rather what they see.

What generally can be said is that (lateral) reflections have an impact on perceived image size (ASW) and width of sound stage. Later reflections (>80ms) create envelopment (LEV aka "You are there"). The latter being the prime argument for multichannel.

 

[JanRSmit]

There is no such research based on controlled (!) listening tests I'm aware of, just a myriad of audiophoolish "facts" ("It's true because I heard it!") filling up tens of thousands (millions?) of posts on social media.

Sight is a powerful bias that can and will override what is heard, e.g. ventriloquism effect. Most of what people hear is rather what they see.

What generally can be said is that (lateral) reflections have an impact on perceived image size (ASW) and width of sound stage. Later reflections (>80ms) create envelopment (LEV aka "You are there"). The latter being the prime argument for multichannel.

What i mean with dimensionality is the width and depth and the positioning of sounds in that 'space' from the loudspeaker plane to (sometimes far) behind that plane. What to my ears occurs is that f.i. when putting speakers on each side of a big furniture the sound the depth collapses to the loudspeaker plane and the positioning in the width gets disturbed. So , in my view, it looks like the spatial cues in the music get distorted.

Regarding multi-channel i have yet to hear such a situation that is convincing to me. Envelopment is an interesting aspect, at this moment for me it is mostly more "it is there" w.r.t. the sound reproduced than "i am there" , this depends on the recording. The apparent source width (ASW) can occasionally extend to beyond the physical width so to say.

W.r.t. the myriad of "facts" you refer to i agree (for me just background noise ;-)), as well that one listens to what one sees (that switch takes place somewhere in the first year after birth, so i was told by ENT specialists). Must say however that i normally listen with eyes closed, even in concerts or when watching talk-shows on TV. Also when i started ( mid-seventies) with stereo i became quite focused on soundstage (width, depth, positioning of voices/instruments). It is how my brain is wired i think, as with my vision it is the same, as my optician also observed.

 

[youngho]

There is no such research based on controlled (!) listening tests I'm aware of, just a myriad of audiophoolish "facts" ("It's true because I heard it!") filling up tens of thousands (millions?) of posts on social media.

I believe that this is a difficult topic to explore in a truly controlled fashion. Moving a speaker closer to the front wall changes its frequency balance, tending to increasingly tilt up below 500-1000 Hz with proximity, as well as changing the comb filter with the first null increasing in frequency with proximity, so multiple variables come into play. If one does this in a room with stereo loudspeakers, then the listening position should be similarly moved closer to the front wall in order to maintain the subtended angle with respect to the loudspeakers, but then this may change the effects of room modes as the listening position changes with respect to nodes and antinodes. One could perhaps do this in an anechoic chamber by placing a rigid barrier behind the loudspeaker, though that doesn't change the balance and comb filter issues. I posted before a report (https://augene.blogspot.com/2020/10/listening-in-anechoic-chamber.html) where the speakers were placed closer to the absorptive boundaries themselves, which could potentially address the balance and comb filter issues to some extent (as anechoic chambers are only rated down to a relative cut-off frequency), though no frequency response curves were provided.

However, sophisticated auralization setups like those referenced here (https://audiomediainternational.com/bo-taps-genelec-for-new-virtual-reality-lab/) could allow for rapid comparison of different setups (for example, signals recorded in an anechoic chamber with a rigid boundary or else with loudspeaker proximity to an absorptive boundary). The Archimedes project did not investigate effects of front wall reflections, and I can't tell if it properly addressed the differences in frequency response with respect to the varying frequency spectrum of the reflections relative to direction from the on-axis.

What i mean with dimensionality is the width and depth and the positioning of sounds in that 'space' from the loudspeaker plane to (sometimes far) behind that plane. What to my ears occurs is that f.i. when putting speakers on each side of a big furniture the sound the depth collapses to the loudspeaker plane and the positioning in the width gets disturbed. So , in my view, it looks like the spatial cues in the music get distorted.

Putting speakers next to furniture introduces the possibility of diffraction effects. In this post (https://www.audiosciencereview.com/...can-this-be-settled.29550/page-5#post-1057682), I referenced several sources who probably wouldn't be considered by most to fall under the "audiophool" category, namely Sigfried Linkwitz, Floyd Toole, and Geoff Martin. However, you would likely consider my post to be just more background noise.

 

[markus]

What i mean with dimensionality is the width and depth and the positioning of sounds in that 'space' from the loudspeaker plane to (sometimes far) behind that plane. What to my ears occurs is that f.i. when putting speakers on each side of a big furniture the sound the depth collapses to the loudspeaker plane and the positioning in the width gets disturbed. So , in my view, it looks like the spatial cues in the music get distorted.

The reflection from the front wall is a spectrally distorted version of the direct sound. At least with common cone/dome loudspeakers that are omni at the low end and get more directional at higher frequencies. One would think that eliminating that reflection (by moving the speaker at/in the front wall) would improve any perception of depth.

 

[JanRSmit]

Putting speakers next to furniture introduces the possibility of diffraction effects. In this post (https://www.audiosciencereview.com/...can-this-be-settled.29550/page-5#post-1057682), I referenced several sources who probably wouldn't be considered by most to fall under the "audiophool" category, namely Sigfried Linkwitz, Floyd Toole, and Geoff Martin. However, you would likely consider my post to be just more background noise.

I would not consider you or Floyd Toole or Siegfried Linkwitz or Geoff Martin a "audiophool", on the contrary. Same goes for Markus. I use the book Sound Reproduction as a source and as a direction into the massive amount of research results available. Your post actually triggered me to look into Floyd Toole's book regarding this, only to find out that this particular area is not really covered, if i am not mistaken. Be it that the paragraph's about his personal home set-up's are implicitly indeed covering the front-wall challenge. Your post also linked to a anecdotal publication of Geoff Martin about achieving distance and depth and what his punchline states correlates with my experiments recently done in my living room, where i made a make shift reduction in directivity. Also i purchased a set of Genelec 8010 speakers and those appear also to be less infulenced by the front wall distance. Need to do more testing though.

 

[Frgirard]

Measurements are the judge of peace.

 

[youngho]

Putting speakers next to furniture introduces the possibility of diffraction effects.

I had mentioned diffraction in another post in an unsupported context, but I did find a few quotes to support effects on spatial perception:
https://www.linkwitzlab.com/diffraction.htm: "Diffraction effects are always spatially localized"
https://www.diyaudio.com/community/threads/baffle-diffraction.317122/page-12#post-5568136: "Diffraction is mostly an imaging problem," also mentioned by Earl Geddes elsewhere in the discussion

I wonder if there's a possibility that boundary proximity itself may also cause diffraction, in an opposite manner to how the speaker baffle edge results in a change in pressure as waves sound expand from half space (2 pi) to full space (4 pi), then the opposite change in pressure from full space to half space again.

Also i purchased a set of Genelec 8010 speakers and those appear also to be less infulenced by the front wall distance.

These have a bass tilt control that can help compensate for boundary proximity

 

[Frgirard]

I had mentioned diffraction in another post in an unsupported context, but I did find a few quotes to support effects on spatial perception:
https://www.linkwitzlab.com/diffraction.htm: "Diffraction effects are always spatially localized"
https://www.diyaudio.com/community/threads/baffle-diffraction.317122/page-12#post-5568136: "Diffraction is mostly an imaging problem," also mentioned by Earl Geddes elsewhere in the discussion

I wonder if there's a possibility that boundary proximity itself may also cause diffraction, in an opposite manner to how the speaker baffle edge results in a change in pressure as waves sound expand from half space (2 pi) to full space (4 pi), then the opposite change in pressure from full space to half space again.

These have a bass tilt control that can help compensate for boundary proximity

Definition of diffraction? The same as in optics

My brain is programmed to "speakers against the front wall is the better location".
If the depth is embedded in the recording, the depth is.
The max depth is obtained with the total darkness.

 

[krabapple]

Mine seems to be programmed to 'speakers a few feet out from the front wall makes me happier'.

stupid brain!

it does prefer dim lights when listening

 

[youngho]

Definition of diffraction? The same as in optics

Yeah, I didn't think it through properly, but I had wondered if the boundary proximity might affect the perception of diffraction resulting from the speaker enclosure itself in some way compared with freestanding.

 

[Deleted member 46664]

Apologies if this has been summarized already on ASR but I could not find it.
Based on this image from Genelec, shouldn't all full-range speakers be near to the front wall?
I have heard the advice that for best stereo image the speakers should be away from the front wall.
Is this "away from the front wall" advice because:
Or, perhaps "away from the front wall" is total nonsense?

The backs of my speakers are currently 6 inches from the front wall of my listening area...
They sound great.

The hump at 50hz is a room mode ... I use only a smidge of EQ to knock it down.

But in another room or area the same positions might sound like crap. The problem is that rooms are like snowflakes, every one is different

When doing setups I have a set of starting points ... the "golden triangle" but once I start measuring and adjusting, almost nothing ever stays in it's starting positions. My only rule is that whatever I do to the left speaker I also do to the right... to keep that triangle going. You want your speakers equal distances and equal angles from your main listing position (sweet spot). Even small moves of 1/4 inch can matter in some cases.

So... my suggestion is to fuss with it, until you like it ... then just relax and enjoy.

 

[mightycicadalord]

My experience has been so far, placing near front wall evens out low end, but midrange is wrecked and imaging takes a hit.

Now they are 3ft from the wall and low end region sucks but imaging is great. Can't win lol.

 

[Deleted member 46664]

My experience has been so far, placing near front wall evens out low end, but midrange is wrecked and imaging takes a hit.

Now they are 3ft from the wall and low end region sucks but imaging is great. Can't win lol.

1 1/2 feet?

 

[mightycicadalord]

1 1/2 feet?

probably tried it and didn't like it for some reason, honestly can one even get the 80-200hz range to look like right? Doesn't matter where I put things I always get nulls in there. Tis frustrating.

 

[Thomas_A]

probably tried it and didn't like it for some reason, honestly can one even get the 80-200hz range to look like right? Doesn't matter where I put things I always get nulls in there. Tis frustrating.

You can get nulls irrespectively of the distance between wall to speaker, depending on room dimensions and seating position. A speaker sitting close to its wall, or in-wall, just solves one issue.

 

[Cote Dazur]

So much focus on where to place speakers when where you seat in relation to the room size and what is behind you and how far are you from what is behind you is much more important. Also more mportant than how far speakers should be to the wall is having nothing in the triangle you form with your speaker.
In my main room my main speaker are design to play against the wall, so that is easy, I seat about 38% into the room.
Speaker away from side wall with diffuser on the wall.
On good recording soundstage is very impressive, on bad recording it is nothing special.

 

[Deleted member 46664]

probably tried it and didn't like it for some reason, honestly can one even get the 80-200hz range to look like right? Doesn't matter where I put things I always get nulls in there. Tis frustrating.

I bet it is ... but then frustration is the most common outcome from perfectionism, so it's kind of expected.

 

[mightycicadalord]

I bet it is ... but then frustration is the most common outcome from perfectionism, so it's kind of expected.

I don't even want perfect I want 80 to 200 to not just disappear. Plenty of others doing it with cheaper and smaller rooms so I guess. I just have bad luck with my room.

 

[Tom C]

I have to believe that a solid ring of subs surrounding a room would eliminate any practical null.
Are you treating the graph? Or an actual perceived deficiency in the sound?

 

[Deleted member 46664]

I don't even want perfect I want 80 to 200 to not just disappear. Plenty of others doing it with cheaper and smaller rooms so I guess. I just have bad luck with my room.

Without doing sweeps in your room I have no way to know what the cause is ... Best I can suggest is to try moving things in relatively small increments and see if you can fine tune the situation with positioning or even rearranging the furniture.

There is one quick check, just to be sure, are your speakers hooked up out of phase, by any chance?