Soundstage and imaging

[valve_integrator]

We are all perfectly aware of the fact that the playback experience can be enhanced substantially by going beyond the traditional two channel setups, but it's just not practical to do so in most cases.

Not practical to do so?
I have been running such systems since at least 1977-78.
Never been an issue.

I have been making the point all along about the limitations of 2 channel stereo, - the fact this so called "soundstage" is non existent, (and as shown, the phantom centre, is gone simply when out of that narrow little "sweet spot").
You can all be in denial if you like, and hence groupthink.

You don't get this with multi-channel (stereo) reproduction- especially when the rear channels are properly spaced and the levels correct.
This thread is about imaging, not even about matrix surround or atmos or anything like that.
Prof Malham's paper is quite clear on all that, easy to download.

NB:-
I can assure you the surround recordings we made, were in such a totally different league from anything in stereo (eg. Wintereise - duo Arsenal Metz, Brahms requiem with full choir, Prince Igor - Russian opera and Skatalites live to mention just a few.).

I can assure you just multi channel stereo is a massive improvement on that horrible flat stuff, and quite easy to do.
Ask Wilkes, if you don't believe me.

 

[Ricardus]

I don’t think so. A bot would make more sense and write more fluidly.

Fair.

 

[Ricardus]

Well let's see about if you would like the same nonsense comments about what you post. eh clap clap!

You literally can't. Which is how I know you're a bogus account. You didn't even read what I wrote.

I don't have a low post count, and I am not a recent signup.

 

[MattHooper]

Everybody already knows that. I really can't understand why you think it's supposed to be such a revelation.

Again, the term "soundstage" as discussed in this thread is defined within those limitations. Nobody is under the delusion that it's able to break those bounds.

We are all perfectly aware of the fact that the playback experience can be enhanced substantially by going beyond the traditional two channel setups, but it's just not practical to do so in most cases. I don't see the so called "groupthink" anywhere.

And the response was to simply repeat the same thing again to you.

Fruitless.

The internet is a strange place.

 

[Killingbeans]

Not practical to do so?
I have been running such systems since at least 1977-78.
Never been an issue.

For you.

Most non-enthusiasts have reverted to small mono setups these days and are perfectly happy.

The vast majority of people in the hobby have chosen two channel setups as a great compromise between practicality/manageability/WAF and immersiveness.

Putting the label "groupthinker" on all those who do not seek to expand the experience via a multichannel setup, seems a lot like elitism.

 

[MattHooper]

For you.

Most non-enthusiasts have reverted to small mono setups these days and are perfectly happy.

The vast majority of people in the hobby have chosen two channel setups as a great compromise between practicality/manageability/WAF and immersiveness.

Putting the label "groupthinker" on all those who do not seek to expand the experience via a multichannel setup, seems a lot like elitism.

Indeed. A symptom of not being able to think outside one's own experience and set of interests.

"It's never been an issue for me: I found time to climb Mount Everest, I don't see why it's not practical for others..."

 

[tmuikku]

I think most of the time when people talk about "stage width" they refer to something that goes beyond the confinement of the speakers and the listening room.

I assume it has something to do with the mischmasch of direct and reflected sound energy that hits you, and how your brain decodes it into something that possibly adds to this particular part of the illusion.

Some brains are probably more suggestible than others to the effects that can artificially "expand" the experience. Don't know. Pure conjecture on my part.

Hi,
all of it depends on listening distance.

If you listen with small (enough) stereo listening triangle so that direct sound is strong enough compared to room sound the local room rougly disappears and stereo image is mostly between speakers, but al around you, envelopment. Space them bit further out, to like 45deg angle from median plane instead of the normal 30deg of equilateral triangle, and the image can be huge. But not beyond speakers. Perhaps it can, I have experience of normal living room only, not properly acoustically treated listening room.

If you listen too far away, other side of the room, no toe-in with speakers, like in many many photos of hifi setups, you have very strong sound from the local room. Here the image, actually the image is hazy blob so sound stage can be quite wide, wider than the speakers. But this really isn't as big as it can be eyes closed with close listening, its your room and not the environment imprinted in the recording

so, question is do you listen close or far?

 

[tmuikku]

I think people underestimate the influence of phase coherence in reproducing tangible spatial illusions.

This is exacerbated by complicated daw recording chains that use various non phase coherent filters / eq, with the ultimate result of an impressionistic rendition rather than a realistic one.

This may be one reason why some of the most " real " high fidelity recordings were done very simply... ( as in, one of the reasons they sound so real is the simplicity of the recording chain, which as a consequence keeps the phase coherence intact) - and those types of recordings typically used simple crossed mics or similar strategies, which capture the original signal in a simple manner, and minimise mixing which may dilute the phase clarity of the direct sound.

Look for David Griesinger papers, phase coherence is what allows hearing system to pick out important sounds from all the.noise around. It is pitch detection and localization also depend on it, gives engagement and draws involuntary attention and so on.

I think the phase coherence can be ruined in multiple ways, in the recording and mixing stages already, perhaps some with playback electronics but especially by our listening rooms. Also speakers with diffration and all kinds of secondary sounds and stuff. It is also frequency dependent, important stuff on the midrange. Anyway, I'm probably not too accurate here as I'm only enthusiast

It turns out that stereo image is great if just listen close enough distance, where room sound doesn't ruin it anymore and brain can separate the important direct sound and room sound as separate things, clarity and envelopment.

See this for example: http://www.davidgriesinger.com/Acoustics_Today/AES_preprint_2012_2.pdf

Taking it to extreme: basically it is not possible to have engagement, hear phase coherence, nor envelopment or clarity if direct to reflected sound ratio is too low and phase information is lost. For home stereo setups without acoustic treatment this means very close listening distance. Having said that, the close sound can be anoying at times and probably reveals all problems in the playback chain, while listening far enough its more mellow and easy going mush Perhaps many people like it this way because that is what they have used to, or what they listen to, practical issues and so on. I like the close sound, for some reason. It is definition of hifi to me to be within the sound of the recording, 3D experience almost.

What I'm getting at is that everyone should know about this stuff in order to be able to discuss about stereo image qualities. Everyone needs to know context which they have and like, and know if words of others are relevant or not. Everyone should find out if they can find transition between the two, a critical distance where local room more or less disappears and perception dives into the recording.

ps. I do not know if it is common to have the close sound happen but I suspect that it is. I think very good stereo sound is available in most homes with almost any decent playback system, just go and shrink your listening triangle. I hope people would try to listen for transition between the two and write if what they found, or didn't.

 

[MattHooper]

Everyone should find out if they can find transition between the two, a critical distance where local room more or less disappears and perception dives into the recording.

That's often been my goal and, in perceptual terms, it can be amazingly successful. I could just chalk it down to my personal perception, but it has been the perception of many guests listening to my system as well "It's like I'm right there, peering in to the studio hearing someone playing..."

 

[tmuikku]

It correlates what Griesinger writes, you've got engagement, attention, clarity all that, recording and your room are perceived separately by brain. Brain considers the sound on the recording important and pays attention.

To me, hearing the transition at critical distance at home was a very peculiar thing and it took some time to find out what it is all about and finally found out it correlates well with Griesinger papers and lectures. It has been such a revelation since.

Basically it has rooted my perception to written concepts and it is now possible to reason a lot of stuff against it. A lot of confusing advice and ideas seem quite clear if put into context of either side of the audible critical distance.

I've been writing about it lately, a lot, in various threads when ever there has been a suitable context. I think everyone should hear the transition in order to be confident what they hear and what others (likely) hear and so on, common ground with perception. My main motivation is to lure others discuss about this, I'm not sure how widely known, or unkown, all this is. Or how audible it is to others with their various setups. It seems super important though, if you didn't notice already from my enthusiasm

Important bit here is that the transition at critical distance seems very stark, in my setup it's literally one step. I can step inside almost 3D sound, or step out back to my room and have it 2D somewhere at speaker direction. Switching between the two is so easy and fast I can evaluate sound of my room, how room and envelopment are perveived and so on. All hifi adjectives suddenly have a context I can shove them in and kind of know what it supposed to sound like.

Griesinger work is very important I think, it tells you what hou hear and what you don't hear, either side of the critical distance. There is even maths how to measure it called LOC, which will indicate where perception changes. His work is mostly on auditoriums and concert halls, but like in the paper I linked earlier he seems to associate the same stuff also to loudspeaker concept.

Well, take my words as from any enthusiast as I probably do not know much of it, only what I hear in my setup and that it seems to be what Griesinger has found out and then reasoning with it. I really encourage everyone interested in stereo sound to study his work and listen the phenomenon them selves to determine if its something meaningful.

 

[AudioJester]

Not practical to do so?
I have been running such systems since at least 1977-78.
Never been an issue.

I have been making the point all along about the limitations of 2 channel stereo, - the fact this so called "soundstage" is non existent, (and as shown, the phantom centre, is gone simply when out of that narrow little "sweet spot").
You can all be in denial if you like, and hence groupthink.

You don't get this with multi-channel (stereo) reproduction- especially when the rear channels are properly spaced and the levels correct.
This thread is about imaging, not even about matrix surround or atmos or anything like that.
Prof Malham's paper is quite clear on all that, easy to download.

NB:-
I can assure you the surround recordings we made, were in such a totally different league from anything in stereo (eg. Wintereise - duo Arsenal Metz, Brahms requiem with full choir, Prince Igor - Russian opera and Skatalites live to mention just a few.).

I can assure you just multi channel stereo is a massive improvement on that horrible flat stuff, and quite easy to do.
Ask Wilkes, if you don't believe me.

Could you share pics/measurements of your setup? Genuinly curious as to what you are doing differently.

I feel like it was the 90's when many of us started realising that multichannel was much better for soundstage/imaging/spatial ques. But the recording industry has not kept up with quality content as multichannel setups are clearly still a small minority.

 

[tmuikku]

Ok, consider this: here on ASR there is lot of talk about speakers and even comparisons and subjective reviews.

Now, consider there are two speakers reviewed, the other one gets huge praise, while the other one gets a meh. But, what if audible critical distance for each is different, and they got opinionated from different sides of it?

Honestly, I have not read much reviews so I don't know if reviewers tell what distance they listen at, what is room acoustics and which side of critical distance they personally prefer. If they do not, then perhaps some assumptions can be made from all information available. I would assume audio and acoustics professionals probably do know about it and likely mention it, while many of us mortals do not. This serious disadvatage for the receiver.

Now, the two speakers could have had similar review if they both were evaluated same side of critical distance. But, the review might still be meaningless to you if you prefer the other side you like! I mean, any advice given or taken makes sense only if both parties know about the critical distance and communicate about it, otherwise it could be exactly wrong advice. Well, with the stereo image context.

Confusing? hell yeah, unless you and the reviewer both are aware about it and understand and communicate about it.

Have fun listening your stereo everyone!

 

[Deleted member 21219]

When you watch a sci-fi movie, you know it's not real, but you have suspension of disbelief.
Because you have suspension of disbelief, your mind generates an artificial "realism".

When you listen to a recording, you know it's not real, but you have suspension of disbelief.
Because you have suspension of disbelief, your mind generates an artificial "realism".

The hardware (the audio equipment) is important, but the software (our mind) is even more important.

That's my story and I'm stickin' to it.

Jim

 

[tmuikku]

Exactly, and when you persuade it suitably then a best possible outcome should be reached. I mean thats the end goall, right?: to have maximum enjoyment of what we grave for, what one is looking for? And I think it is either side of the perceived critical distance and everyone has to fogure it out themselves or perhaps neither side is good if two channel stereo is not your thing.

 

[tmuikku]

Ok here is how to listen for it:
Make quite small stereo listening triangle, 2m or 6ft per side, assuming european livingroom. Toe speakers in some. Try keep ears at suitable listening height, and listening axis, we want to hearing system consider direct sound important. Then play pink noise or spoken word through the system. Put same mono signal to both channels. Goal with the setup is to enable very strong phantom center happen.

Critical distance seems to me happen at some distance from speakers, where level of Direct sound compared to Room sound is high enough.

To find this audible critical distance, start walking back and forth along centerline between speakers always staying equidistant from both. This changes your distance to speakers and makes direct sound louder when you move forward, and quieter when moving backward. Sound in the room is pretty much constant anywhere, so moving closer increases the D/R ratio.

Now, when D/R ratio at some important frequency bandwidh gets high enough the audible transition seems to happen, and its quite sudden. This is the perceived critical distance. If you move further in forward direction the sound pretty much stays the same, but if you move backward you eventually transition back beyond and it's the other hazy sound now everywhere. Roughly on/off change in perception.

Listen like so: while the noise or spoken word is playing and you moving closer or further from speakers on the centerline, listen perception of the phantom image. When I am too far, beyond the critical distance, the phantom center seems diffuse all around between speakers, hazy sound in front of me. Moving closer suddenly the phantom center gets focus, localizes right between the speakers and appears quite small in size, clarity of it seems to increase. The sound is still in front of me but I can also listen what surroundings sound and its kind of calm feeling, almost a silence kind of feel to it, the hazyness seems to have disappeared and the speakers sound almost mute.

Thats the transition, distance where perception changes and brain lifts the phantom out of all the noise in the room. The sound gets your attention

If you do not hear this, try change toe-in off the speakers, verify they are balanced and so on. Pull them closer together if you must. Also further from boundaries.

It is the clear compact nice phantom center with dual mono signal which is what you are trying to perceive. Back of the room you probably are beyond the critical distance and perceive hazy sound. Now go and find transition between the two. It might be in front or back of you, or maybe you already are right at it!

Have fun! and please report somewhere if you try it and find it's something usefull! At least assure for yourself which side you like better, and with which records!

 

[Emlin]

It's all about accurately reproducing the reverb on the recording and not letting that be swamped by the reverb of your room.

 

[MattHooper]

Listen like so: while the noise or spoken word is playing and you moving closer or further from speakers on the centerline, listen perception of the phantom image. When I am too far, beyond the critical distance, the phantom center seems diffuse all around between speakers, hazy sound in front of me. Moving closer suddenly the phantom center gets focus, localizes right between the speakers and appears quite small in size, clarity of it seems to increase. The sound is still in front of me but I can also listen what surroundings sound and its kind of calm feeling, almost a silence kind of feel to it, the hazyness seems to have disappeared and the speakers sound almost mute.

Thats the transition, distance where perception changes and brain lifts the phantom out of all the noise in the room. The sound gets your attention

Interesting description. The pretty closely mirrors my experimenting with speaker/listener position. I usually get an initial speaker set up, some of it constrained by the ergonomics of my room, but then I have my listening sofa on big sliders so I can slide it back and forth easily, within about a 2 foot range or so. Reaching that distance where the sound "clicks" in to entering the space, in the way you describe, is fascinating, especially as it can be a matter of inches sometimes (for the greatest effect).

 

[goat76]

Ok here is how to listen for it. Make quite small stereo listening triangle, 2m or 6ft per side. assuming european livingroom. Then put on pink noise or spoken word, same signal to both channels for very strong phantom center.

Critical distance seems to me happening at some distance from speakers,where level of Direct sound compared to Room sound is high enough.

Start walking back and forth along centerline between speakers always staying equidistant from both. This changes your distance to speakers and makes direct sound louder when you move forward. Sound in the room is pretty much constant anywhere, so this increases the D/R ratio.

Now, when D/R ratio at some important frequency bandwidh gets high enough the audible transition seems to happen, and its quite sudden. This is the perceived critical distance. When you move more forward the sound pretty much stays the same, but if you move backward you transition beyond and its the other sound now everywhere at the perceived critical distance and beyond. Roughly on/off change in perception.

Listen like so: while the noise or spoken word is playing and you moving closer or further from speakers on the centerline, listen perception of the phantom image. When I am too far, beyond the critical distance, the phantom center seems diffuse all around between speakers, hazy sound in front of me. Moving closer suddenly the phantom center gets focus, localizes right between the speakers and appears quite small in size, clarity of it seems to increase. The sound is still in front of me but I can also listen what surroundings sound and its kind of calm feeling, almost a silence kind of feel to it, the hazyness seems to have disappeared and the speakers sound almost mute.

Thats the transition, distance where perception changes and brain lifts the phantom out of all the noise in the room. The sound gets your attention

If you do not hear this, try change toe-in off the speakers, verify they are balanced and so on. It is the clear compact nice phantom center with dual mono signal which is what you are trying to get. Back of the room you probably are beyond the critical distance. Find transition between the two.

Have fun! and please report if you try it and find its something usefull Or have anything to comment on

I think people should try your suggestion and set up their speakers with a way smaller listening triangle than what they probably are used to, it makes a significantly different when it comes to hearing the image and depth of what's actually in the recording when the ratio of the direct sound is optimized vs the reflections from the listening room.
I have come to the same conclusion as you, not by doing it exactly like your test but simply by shrinking my listening triangle to the point where I hear more "into" the recordings than listening to my own room.

Finding the right distance between the loudspeakers is also highly critical, too large a distance and you end up with a washed-out sounding phantom image. When you find an optimal distance between the two speakers, the phantom center can sound almost as solid as if a physical center speaker is used in the setup. And with that, you will know that you have "anchored" the sound from the two loudspeakers in the stereo setup and that they are reproducing a unified stereo image, and by that, pretty much everything including the finer details that paints the three-dimensionality (if the recording contains such information) will also be optimized and have better "focus".
When the "right" distance has been found for optimizing both the direct sound ratio and a distinct-sounding phantom image is found, toe-in can be used to fine-tune it even further.


When looking at pictures of people's HiFi systems, many people seem to have a somewhat large listening triangle where the ratio of the direct sound is probably pretty low vs their room reflections. It's as if they let the room size dictate how far away they sit from their speakers, almost as if it's a rule that a fairly large room is the deciding factor of how large the listening triangle ends up being, and that the listening position must be right against the wall on the opposite side of the room.

 

[MattHooper]

Finding the right distance between the loudspeakers is also highly critical, too large a distance and you end up with a washed-out sounding phantom image. When you find an optimal distance between the two speakers, the phantom center can sound almost as solid as if a physical center speaker is used in the setup. And with that, you will know that you have "anchored" the sound from the two loudspeakers in the stereo setup and that they are reproducing a unified stereo image, and by that, pretty much everything including the finer details that paints the three-dimensionality (if the recording contains such information) will also be optimized and have better "focus".
When the "right" distance has been found for optimizing both the direct sound ratio and a distinct-sounding phantom image is found, toe-in can be used to fine-tune it even further.

Even when you have your center imaging dialed in pretty well, one can notice that hard panned instruments coming from a single speaker can have a presence, solidity and even more realistic sense of timbral complexity, vs an instrument or voiced panned to the center. I presume this is due to the problems in stereo (comb filtering, crosstalk etc) .

Still, the relative solidity of a center image can be awfully impressive. I have a center channel for my home theater back behind, in between my two channel speakers, and it's routine for guests to say afterward "Oh, I thought a lot of it was coming from that speaker (center channel)."

And speaking of getting a locked in center image, I have mentioned before how I've been using a single curved diffusor behind and between my L/R stereo speakers (leaned up against, or on top of, my center channel). It produces an amazing effect of "locking in" images between the speakers. Central images, voices, instruments, drum kicks/snares take on a density and focus, a solidity, that I've never heard before. Much closer to the character of sound coming from a hard panned sound.

 

[Emlin]

Even when you have your center imaging dialed in pretty well, one can notice that hard panned instruments coming from a single speaker can have a presence, solidity and even more realistic sense of timbral complexity, vs an instrument or voiced panned to the center. I presume this is due to the problems in stereo (comb filtering, crosstalk etc) .

Still, the relative solidity of a center image can be awfully impressive. I have a center channel for my home theater back behind, in between my two channel speakers, and it's routine for guests to say afterward "Oh, I thought a lot of it was coming from that speaker (center channel)."

And speaking of getting a locked in center image, I have mentioned before how I've been using a single curved diffusor behind and between my L/R stereo speakers (leaned up against, or on top of, my center channel). It produces an amazing effect of "locking in" images between the speakers. Central images, voices, instruments, drum kicks/snares take on a density and focus, a solidity, that I've never heard before. Much closer to the character of sound coming from a hard panned sound.

Words. Just words. No information.