The perfect speaker is room dependent - wide vs. narrow directivity and more

[tmuikku]

Now, I'd like to raise a question, not sure if its appropriate for this particular thread but here it is as its related to the topic

Assume you've got perfect horizontal directivity, what ever that is, but imaging and spaciousness are 3D stuff at best aren't they? What about height and depth? If image is attached to the speakers (height and or depth wise) can we do something about it with directivity and positioning? What is the situation with your speaker setup, nice and wide image due to optimized lateral reflections, but not very tall? or is it full "front wall painting" or even a 3d show?

 

[tmuikku]

Sub-optimal lateral reflection path lengths can still be beneficial. Ten milliseconds delay relative to the direct sound is the target Earl Geddes mentions, and my understanding is that Earl's source for the psychoacoustics behind that figure is researcher David Griesinger: "Transients are not corrupted by reflections if the room is large enough - and 10ms of reflections free time is enough." (This is the "short version" of the thinking behind that 10 milliseconds target.)

The cross-firing configuration you mentioned earlier will delay the first significant lateral reflections by about ten milliseconds (relative to the direct sound) in a 12-foot-wide room.

Yes this is very logical, making the best out of a situation. Quick check on a specular reflection calculation shows ~12ms for 5m wide room with ~3m stereo triangle listening setup and this or 12 foot would be in range of typical living rooms I've been in.

I like to think directions, where to shoot good and worse stuff from a loudspeaker. Inevitably we are going to have some good and less good sound emitted to some directions from any given loudspeaker and to make best of such system try point the good stuff to important directions and worse stuff for less important. By Important I mean what hearing system eventually perceives the sound in our room. Direct sound plus the six first early reflections are the most important directions being loudest and arriving first. If one optimizes direct sound and the two lateral side wall reflections with positioning and perhaps utilizing directivity, what about the rest four? Are they fine as is as long as DI is smooth? or how to further optimize the system, is there any point? Any of them first reflections could either help, be neutral or be detrimental for perceived sound quality. Which ones are not helpfull and can be just attenuated as much as possible, at least the detrimental ones if any? How much attenuation? These kind of questions have been in my head recently.

 

[Duke]

Now, I'd like to raise a question, not sure if its appropriate for this particular thread but here it is as its related to the topic

Assume you've got perfect horizontal directivity, what ever that is, but imaging and spaciousness are 3D stuff at best aren't they? What about height and depth? If image is attached to the speakers (height and or depth wise) can we do something about it with directivity and positioning? What is the situation with your speaker setup, nice and wide image due to optimized lateral reflections, but not very tall? or is it full "front wall painting" or even a 3d show?

Assuming we're talking about two channel -

Imo spaciousness is best conveyed by the reverberation tails on the recording, rather than by the inherently inadequate reflection path lengths of our playback rooms, and those reverberation tails should ideally be delivered from all around. I consider the in-room reflections to be the "carriers" for the reverberation tails on the recording, and try to preserve their spectral content accordingly.

Whether two channels in the horizontal plane can convey height information is controversial. There are those who claim to sometimes hear height information, and there are those who point out that there is no logical mechanism for speakers to convey it. I'm not normally aware of hearing height information with two-channel playback, but I have heard it, though I do not have an explanation for how it was conveyed.

If one optimizes direct sound and the two lateral side wall reflections with positioning and perhaps utilizing directivity, what about the rest four? Are they fine as is as long as DI is smooth? or how to further optimize the system, is there any point? Any of them first reflections could either help, be neutral or be detrimental for perceived sound quality. Which ones are not helpfull and can be just attenuated as much as possible, at least the detrimental ones if any? How much attenuation?

Consider all of the following to be amateur-level advice. If you are serious about room acoustics, hire a professional in the field. An acoustician is to room treatment for your room as a crossover engineer is to loudspeaker design for a given combination of drivers.

The floor and ceiling reflections are relatively benign from an imaging standpoint because they arrive at the two ears simultaneously. They have comb-filter effects in the frequency response domain, which are not inaudible but which are perceptually not nearly as detrimental as they look on paper. For a seated listener the floor and ceiling bounce dips and peaks occur at different frequencies because the path lengths to the ear are significantly different, so in practice they tend to fill in one another. Earl Geddes breaks up the ceiling bounce with large wooden slats running side-to-side across his ceiling, and he intercepts the floor bounce with a strategically placed coffee table. I like both of those approaches better than absorption.

For the wall behind the speakers, I'd go with diffusion or broadband absorption, if the speakers are monopoles. If the speakers are bipoles or dipoles or something similar, I'd try to reflect the rear-firing energy in a direction that does not result in a strong bounce straight towards the listening area, with diffusion as a second choice.

For the wall behind the listener's head, I suggest deliberately re-directing the reflections either up or to the sides, such that they don't bounce straight back to the listener's ears. Again diffusion would be my second choice, and broadband absorption as a last resort.

But again if you're serious, hire a real professional. I routinely recommend Jeff Hedback, an award-winning acoustician who is still affordable, and who I have worked with on several projects.

Here is the problem with using absorption that is not broadband: It selectively removes the shorter wavelengths from the reflections, altering the spectral balance. The ear/brain system identifies reflections as such by their spectral content. When the higher harmonics have been reduced in level so much that the ear can no longer correctly identify a reflection as a repetition of a previous direct sound, that reflection ceases to be "signal" and becomes "noise". So poorly-done absorptive treatment can actually reduce the effective in-room signal-to-noise ratio, with the result being a degradation of clarity and timbre and the introduction or increase of listening fatigue.

 

[Tangband]

Now, I'd like to raise a question, not sure if its appropriate for this particular thread but here it is as its related to the topic

Assume you've got perfect horizontal directivity, what ever that is, but imaging and spaciousness are 3D stuff at best aren't they? What about height and depth? If image is attached to the speakers (height and or depth wise) can we do something about it with directivity and positioning? What is the situation with your speaker setup, nice and wide image due to optimized lateral reflections, but not very tall? or is it full "front wall painting" or even a 3d show?

Here is my thoughts.
Most of the depths we hear from a recording and two channel playback is only an illusion . When Im recording chamber musicians, I often have them positioned 4 meters from a big stonewall . This brings a nice acoustic reverberant sound on the recording , but the debth is often an illusion in the listening room . The microphones are often placed near the instruments . When I only use 2 microphones I have to adjust the placements of the microphones for the best illusion , and this means that while the best listeningplace in the concert hall is at row 5, - 8 meters from the musicians , the best recording position for the two microphones is much less distance, often less than 2 meters if there is 3 musicians playing .
When I record a grand piano in a big stone church I set up the two omni microphones about 1 meter from the center of the open lid piano , spaced 53 cm apart.
This often gives a nice reverberant sound on the recording , sounding like you sit 5 meters from the grand piano .

So, in my opinion there is no such thing as a natural depth in the 2 channel recording , even if the recording is done with only two microphones in a purist way . The stereo system is a very flawed system.

In my opinion , the illusion of depth at home comes from how your speakers are set up, how the walls behind your speakers interplay with the direct sound from the speakers , the size of the room , the walls , and the listening position .
Paul McGowan explains this in an entertaining way . And in this particular video, I believe he is right .

 

[Thomas_A]

Here is my thoughts.
Most of the depths we hear from a recording and two channel playback is only an illusion . When Im recording chamber musicians, I often have them positioned 4 meters from a big stonewall . This brings a nice acoustic reverberant sound on the recording , but the debth is often an illusion in the listening room . The microphones are often placed near the instruments . When I only use 2 microphones I have to adjust the placements of the microphones for the best illusion , and this means that while the best listeningplace in the concert hall is at row 5, - 8 meters from the musicians , the best recording position for the two microphones is much less distance, often less than 2 meters if there is 3 musicians playing .
When I record a grand piano in a big stone church I set up the two omni microphones about 1 meter from the center of the open lid piano , spaced 53 cm appart.
This often gives a nice reverberant sound on the recording , sounding like you sit 5 meters from the grand piano .

So, in my opinion there is no such thing as a natural depth in the 2 channel recording , even if the recording is done with only two microphones in a purist way . The stereo system is a very flawed system.

In my opinion , the illusion of depth at home comes from how your speakers are set up, how the walls behind your speakers interplay with the direct sound from the speakers , the size of the room , the walls , and the listening position .
Paul McGowan explains this in an entertaining way . And in this particular video, I believe he is right .

Reproduction is always an illusion of that the musicians are standing in a room behind an invisible front wall, or that you are at the concert hall or venue with the musicians. In case one you will hear the reflections from the recording room (your case the "stone wall") as well as the reflections of your room (side walls, floor, roof etc). I believe that all those reflections contribute to a sense of space. Your recording distance of 2 meters means that the musicians are 2 meter behind your own "invisible" wall; adding 3 meter to your listening position means 5 meter total. You should ideally get the illusion that the musicians are standing a bit behind your wall and not lined up at the wall (as the speakers). There should be no SBIR reflections of speakers and that said wall (meaning damping or in-wall speakers).

Now adding speakers (I have now two top front speakers and two surrounds placed high with down-firing woofers and roof-firing tweeters (angled)), the illusion increases at least for good live recordings using Atmos decoding. The top front speakers add to a more complete opening of the front wall placing the musicians and instruments in front of you, while the surrunds add ambience and more enveloping sound. It gets more life-like and more as you are there. But it is still an illusion.

 

[test1223]

Regarding the heavy toe in I calculated the room width which is needed to get a delay of the reflection from the opposite wall (assuming an stereo triangle)

Listening distance [m]	Room width (toe in 20ms delay) [m]	Room width (heavy toe in 22.5ms delay) [m]	Room width (heavy toe in 25ms delay) [m]
1	6.14	7.00	7.87
2	5.35	6.23	7.09
3	4.58	5.41	6.28
4	-	4.57	5.45

As you can see you get values which actually a lot of living or listening rooms provide. It is also interesting that due to the subtraction of the listening distance (l r speaker distance) in the formula you need a smaller room with higher listening distance.

Good headphone sound is certainly not what I want to hear from speakers.

Yes I can relate to that. I mentioned headphones because of the ability to hear details or exactness which you can only get with speakers if they provide a higher amount of direct sound. This ability is a very important characteristic which also helps to hear the room of the recording and not only to hear all details better.
From what you wrote you are enjoying the sense of being enveloped by the sound? Have you auditioned a good omnidirectional speaker?

Radiation pattern of the speaker does not change the slope of the decay, but more controlled and narrow pattern will give a better initial early decay drop, and reduces the relative level of the reflected sound energy compared to the early direct sound.

Yes, this is typically the case but not necessarily always true. If you design a listening room you can form the RT60 /RT30 curve to some extent.

With more narrow speakers you have to be much more aware of the direction and treatment of the wall where the main beam of the speaker is directed. One trick is to steer the beam in the upper back corners formed by the back wall, ceiling and side wall in an untreated room. With this you get more diffuse reflections which otherwise is harder to achieve with such a speaker.

One could check out actual living /listening room reflection paths / times with some raytracing tools or reflection calculators like this one https://amcoustics.com/tools/amray and try figure out how to make best of it.

Nice tool. Ray tracing is useful for checking first reflections, but beyond that you have to be aware that it is more like a really rough estimate since the diffusion of sound waves plays a very important role in room acoustics and the simulation of that with ray tracing programs is poor if it is included at all.

Whether two channels in the horizontal plane can convey height information is controversial. There are those who claim to sometimes hear height information, and there are those who point out that there is no logical mechanism for speakers to convey it. I'm not normally aware of hearing height information with two-channel playback, but I have heard it, though I do not have an explanation for how it was conveyed.

You definitely can influence the horizontal size of the image with the type of speaker. With a multi way speaker where there is more space between the drivers which produce the sound of 300Hz to 20kHz you get a greater but less precise horizontal image. With a coaxial you get a smaller but more precise horizontal image. You might get both with a good line array but I haven't heard many such builds. From a theoretical stand point it makes a lot of sense since you got a cylindrical wave.

You typically can't place a sound source in a higher or lower spot with stereo speakers.

 

[Byrdsmaniac]

Regarding the heavy toe in I calculated the room width which is needed to get a delay of the reflection from the opposite wall (assuming an stereo triangle)

Listening distance [m]	Room width (toe in 20ms delay) [m]	Room width (heavy toe in 22.5ms delay) [m]	Room width (heavy toe in 25ms delay) [m]
1	6.14	7.00	7.87
2	5.35	6.23	7.09
3	4.58	5.41	6.28
4	-	4.57	5.45

As you can see you get values which actually a lot of living or listening rooms provide. It is also interesting that due to the subtraction of the listening distance (l r speaker distance) in the formula you need a smaller room with higher listening distance.


Yes I can relate to that. I mentioned headphones because of the ability to hear details or exactness which you can only get with speakers if they provide a higher amount of direct sound. This ability is a very important characteristic which also helps to hear the room of the recording and not only to hear all details better.
From what you wrote you are enjoying the sense of being enveloped by the sound? Have you auditioned a good omnidirectional speaker?


Yes, this is typically the case but not necessarily always true. If you design a listening room you can form the RT60 /RT30 curve to some extent.

With more narrow speakers you have to be much more aware of the direction and treatment of the wall where the main beam of the speaker is directed. One trick is to steer the beam in the upper back corners formed by the back wall, ceiling and side wall in an untreated room. With this you get more diffuse reflections which otherwise is harder to achieve with such a speaker.


Nice tool. Ray tracing is useful for checking first reflections, but beyond that you have to be aware that it is more like a really rough estimate since the diffusion of sound waves plays a very important role in room acoustics and the simulation of that with ray tracing programs is poor if it is included at all.


You definitely can influence the horizontal size of the image with the type of speaker. With a multi way speaker where there is more space between the drivers which produce the sound of 300Hz to 20kHz you get a greater but less precise horizontal image. With a coaxial you get a smaller but more precise horizontal image. You might get both with a good line array but I haven't heard many such builds. From a theoretical stand point it makes a lot of sense since you got a cylindrical wave.

You typically can't place a sound source in a higher or lower spot with stereo speakers.

I have only heard a few Omnis, and dipoles. Most were disqualified by having obvious colorations or what I felt was an unrealistically diffuse sound field. In any case, I feel my living room likely has too much glass to sound good with omni-directional speakers.
Also, I'm perfectly satisfied with the Monitor Audio Silver 8i in that location and have been since 1999. I tried the Sierra 2EX in that room, but I found the 8i superior for large scale music there. It would likely be different in a smaller room. I find the tall and narrow 8i needs a bit more distance for thesound to be properly integrated from all four drivers.
I like the balance of detail and envelopment I get. As I said, my goal is to give a reasonable semblance of concert hall sound. As far as I'm concerned I'm close enough. I'll spend my money on other things now.

 

[Kvalsvoll]

Yes, this is typically the case but not necessarily always true. If you design a listening room you can form the RT60 /RT30 curve to some extent.

And that means changing the room, not the speakers. Yes, the rate of decay, and shape of the decay slope can indeed be changed by changing room acoustics. Then you will observe that this decay slope is the same, with different speakers.

Usually, the slope will be linear. Some rooms are different. Like my Room2, which has more late energy, combined with quite good early decay attenuation.

 

[CherylJosie]

Here is my thoughts.
Most of the depths we hear from a recording and two channel playback is only an illusion . When Im recording chamber musicians, I often have them positioned 4 meters from a big stonewall . This brings a nice acoustic reverberant sound on the recording , but the debth is often an illusion in the listening room . The microphones are often placed near the instruments . When I only use 2 microphones I have to adjust the placements of the microphones for the best illusion , and this means that while the best listeningplace in the concert hall is at row 5, - 8 meters from the musicians , the best recording position for the two microphones is much less distance, often less than 2 meters if there is 3 musicians playing .
When I record a grand piano in a big stone church I set up the two omni microphones about 1 meter from the center of the open lid piano , spaced 53 cm apart.
This often gives a nice reverberant sound on the recording , sounding like you sit 5 meters from the grand piano .

So, in my opinion there is no such thing as a natural depth in the 2 channel recording , even if the recording is done with only two microphones in a purist way . The stereo system is a very flawed system.

In my opinion , the illusion of depth at home comes from how your speakers are set up, how the walls behind your speakers interplay with the direct sound from the speakers , the size of the room , the walls , and the listening position .
Paul McGowan explains this in an entertaining way . And in this particular video, I believe he is right .

This is an interesting take on it.

I've been recording weekend warrior bar bands and free concerts in the park as a hobby, using a variety of techniques.

For a while I tried using a 10 channel mid-side microphone array using 6 multi-polar microphones (Behringer B2 Pro, got them for $500 total from Musician's Friend refurbed) plus a Zoom R24 recorder with 6 channels of phantom power.

I configured one mike as omnidirectional mid and put the other 5 mikes as figure 8 sides in close proximity, with a variety of hardware all screwed together to hold them steady.

The advantage of this arrangement is that I could mix the recording down to 7 channels and write a surround sound file that played back in 9 channel DTS expansion on my home theater. This more or less faithfully reproduced what I heard at the original performance, except of course contaminated with my playback room acoustics. That was helpful because with my hearing loss and especially the distortion of my damaged ears I was having difficulty hearing what I was mixing and I needed a quieter reference playback to be able to objectively evaluate my own mix so I could learn how to compensate for my hearing issues at high SPL when attempting to interpret my live mix in real time.

The disadvantage of this arrangement is that such a monstrous microphone array doesn't fit in front of the band. It looks like some godforsaken aerial antenna from the 1970s hanging off a mike stand that threatens to tip over with a crash if some dancer bumps it, and it obstructs the view. I had to put it by the mixer out in the audience and that is so far away that the direct sound is greatly contaminated by the room acoustics.

Also, it's difficult to fit 6 large diaphragm condensers in close proximity to each other. The ability of that mid mike to discriminate and capture two channels from each side mike was limited by the physical constraint. Either the side mikes were shadowing each other with their ginormous bodies, or they were physically interfering with each other especially in their bulky shock mounts, or they were so far from the mid mike that they weren't doing a very good job of multiplexing the sound and the result was similar to a tweaked Blumlein rather than an XY or mid-side with coincident placement. Front-rear separation was minimal and nearly nonexistent in the treble where smaller misalignments in positioning create huge variation in phase.

It was a nice experiment though. Had a lot of fun with it.

There are some surround sound microphones with four capsules in a single tetrahedron with mikes at the four vertices and DSP to extract a surround sound channel configuration per the user's desire. I think this would have produced better results, but it is an expensive way to go. Field recording engineers who market environmental sounds like trains, traffic, birdsong, babbling brooks etc. use such microphones.

The issue with recording from the perspective of the audience is that the room acoustics of the venue contaminate the recording with a lot of ambient reflections and that is highly evident when playing it back. This is also the case even for outdoor performances where ground reflections, nearby buildings, and treble attenuation from the air are all factors. Plus if the speaker systems at the venue aren't up to snuff or tuned improperly the resulting capture reproduces all those flaws and that's not so great from the perspective of fidelity. The resulting sound when playing back in a home theater is that the sound isn't natural, but for headphones it can sound okay, sort of.

Putting the microphones very close to the sound source minimizes that contamination and allows the stereo or surround speaker system in the playback venue to better emulate the sound coming from the stage in the recording venue, but then the perspective being reproduced is from the performers rather than from the audience.

Adding in some mikes in the audience to the mikes on stage only works during the applause, and then it's still not great, so it's only turned up between songs and turned down during songs.

To best reproduce a 'you are there' recording from the perspective of the audience, it would be best to play back on headphones, or to have stereo or surround speakers right at the listener MLP during playback. That's not a home theater however. It's also not what this guy suggested when he said to turn the walls into speakers.

To pull this off successfully, it's more like putting the speakers into a set of open-back surround-sound headphones that encircle the ears with the captured wavefront of the original recording from the subjective position of a listener in the audience. Then the contamination of room reflections and room ambiance is minimized by maximizing the direct sound reaching the listener, and this should present the best approximation of 'being there' from my 10 channel mid-side mix.

Maybe some day I'll try it with a set of bookshelf speakers in a tight array around my head...could work in just about any listening room so that solves a lot of problems!

But it won't be a good playback system for traditional recordings because it will be lacking the critical ambient contribution of my listening room acoustics that we usually depend upon to approximately model the acoustics of the original venue. Also, with the speakers that close, there won't be much tactile from the deep bass and the room/sofa won't shake. It will lose a lot in translation from not having that physical listening room contributing to the illusion of 'being there'.

 

[test1223]

And that means changing the room, not the speakers. Yes, the rate of decay, and shape of the decay slope can indeed be changed by changing room acoustics. Then you will observe that this decay slope is the same, with different speakers.

Usually, the slope will be linear. Some rooms are different. Like my Room2, which has more late energy, combined with quite good early decay attenuation.

I guess my first explanation was to short. I was trying to emphasize that you can build or optimize a room for a specific speaker and placement. In such rooms the usual behavior often doesn't fit any more. A wider di speaker and narrow di speaker most likely don't shift the RT60 or RT30 curve in such a room but you get two different curves.

 

[tmuikku]

With more narrow speakers you have to be much more aware of the direction and treatment of the wall where the main beam of the speaker is directed. One trick is to steer the beam in the upper back corners formed by the back wall, ceiling and side wall in an untreated room. With this you get more diffuse reflections which otherwise is harder to achieve with such a speaker.

Nice, gotta try this!

Nice tool. Ray tracing is useful for checking first reflections, but beyond that you have to be aware that it is more like a really rough estimate since the diffusion of sound waves plays a very important role in room acoustics and the simulation of that with ray tracing programs is poor if it is included at all.

Yeah, its cool to visualize the first order reflections though, second and third order as well. Many of these would land on the reverberation of the room but bunch happen before. I think its a good way to get insight how the stuff plays out, good food for imagination. Like floor reflection is about always the shortest and how the reflections spread out in time and what not.

You definitely can influence the horizontal size of the image with the type of speaker. With a multi way speaker where there is more space between the drivers which produce the sound of 300Hz to 20kHz you get a greater but less precise horizontal image. With a coaxial you get a smaller but more precise horizontal image. You might get both with a good line array but I haven't heard many such builds. From a theoretical stand point it makes a lot of sense since you got a cylindrical wave.

This seems to be true, tried it with modular multiway speaker, elevating ways with spacers but I can't say what effect it has to image as its just single speaker mono setup but the spectrum definitely spreads out and gets height by spreading the c-c distances. Simply by elevating the whole thing up the whole audio perception moves up. Experimenting more with this after getting stereo pair made some day.

Whats your preference and opinion on the height stuff? point source like coaxial or spread out? Do you elevate speakers above ear level? I suppose most speakers are designed to be listened at certain height and many things change if such speaker is elevated, but if speaker was designed to be higher providing taller image, or at least make the music appear higher up, would it be better? Whats the opinion on this? I'm after musical scene and this height thing is very interesting. Havent had many hours yet to explore with it, and only in mono so looking for tips. This the height thing I asked earlier about, part of 3D image with width and depth although the stereo content doesn't actually have height info in it, like already noted, only the apparent total height changes.

 

[test1223]

Whats your preference and opinion on the height stuff? point source like coaxial or spread out? Do you elevate speakers above ear level? I suppose most speakers are designed to be listened at certain height and many things change if such speaker is elevated, but if speaker was designed to be higher providing taller image, or at least make the music appear higher up, would it be better? Whats the opinion on this? I'm after musical scene and this height thing is very interesting. Havent had many hours yet to explore with it, and only in mono so looking for tips. This the height thing I asked earlier about, part of 3D image with width and depth although the stereo content doesn't actually have height info in it, like already noted, only the apparent total height changes.

We humans aren't very good in hearing the size in vertical direction. The image should also get bigger vertically like it is horizontally with more space between the drivers. I guess the shape of the wave front also plays an important role. You have to get into multi channel panning stuff, I haven't that much knowledge in that field. Placing identical speakers above the stereo speakers might to the trick to increase the vertical size of the image, but you might mess up other areas with this.

I personally didn't like stereo speakers which are places a lot higher than ear level. With stereo you get the center image a bit elevated compared to the height of the driver any way. I don't think you have much benefits by placing the speakers higher other than avoid potential reflections or such stuff.

The depths of the image can be influenced by the reflections of back wall. Dipole speakers or speakers with back firing drivers provide this if they are places more than about 1.5m away from the back wall.

 

[Tangband]

We humans aren't very good in hearing the size in vertical direction. The image should also get bigger vertically like it is horizontally with more space between the drivers. I guess the shape of the wave front also plays an important role. You have to get into multi channel panning stuff, I haven't that much knowledge in that field. Placing identical speakers above the stereo speakers might to the trick to increase the vertical size of the image, but you might mess up other areas with this.

I personally didn't like stereo speakers which are places a lot higher than ear level. With stereo you get the center image a bit elevated compared to the height of the driver any way. I don't think you have much benefits by placing the speakers higher other than avoid potential reflections or such stuff.

The depths of the image can be influenced by the reflections of back wall. Dipole speakers or speakers with back firing drivers provide this if they are places more than about 1.5m away from the back wall.

I have experienced the same thing with three different standmount speakers of slightly different sizes - they all sounded best on a loudspeakerstand that was about 60 cm high . I have three different stands to compare with , 50 cm, 60 and 70 cm.

I think its not just having the tweeter at ear level, its also the thing that you come away a little more from the floor bounce reflex if you have a 60 cm stand compared to a 50 cm. 70 cm on the contrary, started to sound slightly unatural , for unknown reasons.

I have no science behind this experience, only my subjective perceived music enjoyment.

 

[tmuikku]

... With stereo you get the center image a bit elevated compared to the height of the driver any way. I don't think you have much benefits by placing the speakers higher other than avoid potential reflections or such stuff. ...

I need to build another speaker to listen this in stereo, been in single speaker mono for long time. I believe you on this but as always need to experiment first hand as forums don't convey sound only descriptions of it Yesterday I read a lot of forums and found some post that mentioned something along that when hearing system receives conflicting cues for localization it tends to make it perceive higher up as thats the position ears don't provide much cues for, or something along the lines. Couldn't find it again and don't know studies that write about this. It would make sense though that phantom center in stereo system would appear somehow elevated as its made by the brain from cues from two different sources in a room and potentially contains some conflicting cues. Anyway, just speculating.

With elevated system reflections are certainly affected, also the system balance changes when listening outside design axis and especially the vertical axis. Besides angles changing towards vertical first reflections also the lateral first reflections would have slightly different angle and perhaps meaningful change in spectrum, many things change and it might be hard to hear any benefits of elevated speaker position if there are new distractions introduced as well. Well, if there is any benefits.

 

[Thomas_A]

I need to build another speaker to listen this in stereo, been in single speaker mono for long time. I believe you on this but as always need to experiment first hand as forums don't convey sound only descriptions of it Yesterday I read a lot of forums and found some post that mentioned something along that when hearing system receives conflicting cues for localization it tends to make it perceive higher up as thats the position ears don't provide much cues for, or something along the lines. Couldn't find it again and don't know studies that write about this. It would make sense though that phantom center in stereo system would appear somehow elevated as its made by the brain from cues from two different sources in a room and potentially contains some conflicting cues. Anyway, just speculating.

With elevated system reflections are certainly affected, also the system balance changes when listening outside design axis and especially the vertical axis. Besides angles changing towards vertical first reflections also the lateral first reflections would have slightly different angle and perhaps meaningful change in spectrum, many things change and it might be hard to hear any benefits of elevated speaker position if there are new distractions introduced as well. Well, if there is any benefits.

The elevated phantom center in stereo is known psychoacoustically. Eg

News - University of Huddersfield

The University of Huddersfield Repository is an electronic archive of the University's research output.

eprints.hud.ac.uk

 

[tmuikku]

I have experienced the same thing with three different standmount speakers of slightly different sizes - they all sounded best on a loudspeakerstand that was about 60 cm high . I have three different stands to compare with , 50 cm, 60 and 70 cm.

I think its not just having the tweeter at ear level, its also the thing that you come away a little more from the floor bounce reflex if you have a 60 cm stand compared to a 50 cm. 70 cm on the contrary, started to sound slightly unatural , for unknown reasons.

I have no science behind this experience, only my subjective perceived music enjoyment.

How far away do you listen to? the closer the listening distance the more the elevation changes response at listening spot, angles to ear and toward first specular reflections change more. With 3m listening distance elevating speaker 10cm makes only ~2 degree difference and this shouldn't matter much unless very beaming speaker. If listening distance is only 1 meter then this would be roughly 6 degree change. Perhaps ear is very sensitive to issues or features of your speaker response, in room? Have you listened this in single speaker mono? Perhaps the stereo image suffers more than what simple change in angle and thinking change in response suggests. Interesting. I'm not sure how valuable it is to evaluate stuff with mono speaker if "qualities" don't translate for stereo.

Thomas_A, thanks, will read!
edit. nice, too late night to suck the info into imagination but shows how awesome hearing system is and how stereo systems really can't be optimized on all aspect. Perhaps I should stay in mono

 

[Tangband]

How far away do you listen to? the closer the listening distance the more the elevation changes response at listening spot, angles to ear and toward first specular reflections change more. With 3m listening distance elevating speaker 10cm makes only ~2 degree difference and this shouldn't matter much unless very beaming speaker. If listening distance is only 1 meter then this would be roughly 6 degree change. Perhaps ear is very sensitive to issues or features of your speaker response, in room? Have you listened this in single speaker mono? Perhaps the stereo image suffers more than what simple change in angle and thinking change in response suggests. Interesting. I'm not sure how valuable it is to evaluate stuff with mono speaker if "qualities" don't translate for stereo.

Thomas_A, thanks, will read!
edit. nice, too late night to suck the info into imagination but shows how awesome hearing system is and how stereo systems really can't be optimized on all aspect. Perhaps I should stay in mono

If you read about the precedence effect, there is different things happening below 2 ms, between 2 ms-5 ms , and above 5 ms delayed reflected sounds.

My experimenting with this, gives me the conclusion that about 2 ms ( 68 cm ) delayed sound or more, is a crucial point were localization of sounds starts to happen in the brain.

Reflections less than 2 ms delay gonna make the sound very unclear . This happens If you put a speaker on the wall and have no damping material around the speaker. Or If you put a standmount speaker directly on the floor.

2 ms in the precedence effect is about 68 cm delayed soundtravel - this is about the distance to the floor you get for the driveunits on a speaker If the loudspeaker is put on a 60 cm ( 63 cm with feets ) stand. The tweeter in this case gonna be more than 90-95 cm above the floor. So my theory is that it is good to avoid the nearest floor or wall bounce delay of the sound coming within 0-2 ms, at least for midrange and treble frequencies.

If you put the standmount speaker on 40 cm or 50 cm stand you get below 2 ms delayed sound - my experience with floor/wall reflections reaching the microphones in recording sessions is that reflections from 0-2 ms mic-floor or mic - wall should absolutely be avoided . The recorded sound will be very unclear.
The same seems to be happening in the reverse case - the playback situation.

 

[thewas]

2 ms in the precedence effect is about 68 cm delayed soundtravel - this is about the distance to the floor you get for the driveunits on a speaker If the loudspeaker is put on a 60 cm ( 63 cm with feets ) stand. The tweeter in this case gonna be more than 70 cm above the floor. So my theory is that it is good to avoid the nearest floor bounce delay of the sound coming within 0-2 ms, at least for midrange and treble frequencies.

If you put the standmount speaker on 40 cm or 50 cm stand you get below 2 ms delayed sound

Your calculation is incorrect as the floor bounce path is not going purely vertically, so for assumed 70cm tweeter and ears height and 2 meters listening distance the floor reflection is only 1.28 ms delayed, see also https://mehlau.net/audio/floorbounce/

 

[Tangband]

Your calculation is incorrect as the floor bounce path is not going purely vertically, so for assumed 70cm tweeter and ears height and 2 meters listening distance the floor reflection is only 1,28 ms delayed, see also https://mehlau.net/audio/floorbounce/

Thanks for the correction. I have corrected my print, the tweeter will be 90-95 cm above floor level . ( I just measured my Genelec 8340 on my 63 cm stand, and the tweeter is 90 cm above floor level + the depth of waveguide . )

For me there is something in the sound that tells me that reflections below 2 ms delayed sound is bad for sound quality, at least for mid and high frequencies.

 

[Tangband]

Thanks thewas for the calculator .
In this example where the tweeter is 90 cm above the floor ( such as in my case with 8340 on the 63 cm high stand ) , one can see that the reflected sound is about 2.03 ms delayed.
If I compare my 8340 on my 50 cm high stand, the sound is becoming somewhat less clear, even If I angle the speaker so the direct sound reaching my ears are the same .