What is "Sound Stage?"

[Phelonious Ponk]

Tim, Tim, Tim. You are saying perceived position is ONLY contingent on arrival time. I'm telling you that it is also contingent on frequency profile. Micro is spot on that even with one mic and one speaker distance trigger cues can exist. These differences in frequency are things we hear in real life. High frequencies trail off faster than low frequencies as distance increases. That is a fact. The ratio of direct and indirect sound changes over distance. Another fact. We experience this daily and will associate the frequency profiles as near or far. Again one mic, one speaker, conditioned respone, perception of distance.

You're missing the point. I'm not saying position is only contingent on arrival time and I agree with most of what you said above. What prevents these elements from becoming "height information" is the lack of anything in the recording or playback systems, to differentiate them. Is it distant? Sure, got that. Is it off-axis? A lot less likely that there's anything there given the way most microphones work, but I'll give you the point for the sake of argument.

Now you have the signal captured. The recording has picked up a tone from a cello that is X% reflected sound, at X volume, with X FR alterations relative to the close, direct sound. It sounds as if it is "X distant."

X distant where is the question. Up? Down? Out? Back? Left? Right? With one mic, one channel, one speaker there is nothing to differentiate up from down. You have lateral information because you have lateral channels. In the vertical plane your system is mono. So if, in the vertical plane, you hear the standing singer's voice a couple of feet above the seated player's cello, it is because that's where you expect it to be (not that there's anything wrong with that), not because of anything in the recording or the playback system.

Another possibility is that you're sitting too close to a tall driver array that is failing to cohere before it reaches your ears. Of course then, if the cellist plays a high enough note, it will suddenly jump up and join the singer. It's a bit alarming that some audiophiles consider this a quality of better speakers.

And one more time, before I'm misinterpreted again: None of this has anything to do with a "sense" of height, or with speakers projecting a sound stage taller (and wider) than their boxes. All of that happens. Even in my modest system. What it has to do with is the ability of stereo to create a differentiated and even partially accurate vertical image, similar to the horizontal image it creates with its two lateral channels. Stereo does not do this. It cannot do this. You can only place these vertical elements in that plane with your mind.

Tim

 

[bblue]

You're missing the point. I'm not saying position is only contingent on arrival time and I agree with most of what you said above. What prevents these elements from becoming "height information" is the lack of anything in the recording or playback systems, to differentiate them. Is it distant? Sure, got that. Is it off-axis? A lot less likely that there's anything there given the way most microphones work, but I'll give you the point for the sake of argument.

Now you have the signal captured. The recording has picked up a tone from a cello that is X% reflected sound, at X volume, with X FR alterations relative to the close, direct sound. It sounds as if it is "X distant."

X distant where is the question. Up? Down? Out? Back? Left? Right? With one mic, one channel, one speaker there is nothing to differentiate up from down. You have lateral information because you have lateral channels. In the vertical plane your system is mono. So if, in the vertical plane, you hear the standing singer's voice a couple of feet above the seated player's cello, it is because that's where you expect it to be (not that there's anything wrong with that), not because of anything in the recording or the playback system.

Another possibility is that you're sitting too close to a tall driver array that is failing to cohere before it reaches your ears. Of course then, if the cellist plays a high enough note, it will suddenly jump up and join the singer. It's a bit alarming that some audiophiles consider this a quality of better speakers.

And one more time, before I'm misinterpreted again: None of this has anything to do with a "sense" of height, or with speakers projecting a sound stage taller (and wider) than their boxes. All of that happens. Even in my modest system. What it has to do with is the ability of stereo to create a differentiated and even partially accurate vertical image, similar to the horizontal image it creates with its two lateral channels. Stereo does not do this. It cannot do this. You can only place these vertical elements in that plane with your mind.

Tim

Nicely put, Tim.

For the rest, with the exception of just a few: What a bunch of knuckleheads.

--Bill

 

[FrantzM]

if one microphone can provide a sense of height, then one microphone with one speaker ought to provide a sense of lateral placement too? Right? So, why do we need two-ch stereo? To repeat bblue question?

 

[bblue]

Bill,

(I will keep it very short and simple, to increase signal-to-noise ratio and try to avoid the unfriendly graphical proliferation of straw puppets ).

Sorry, but it seems we speak different languages. In real world if the source moves away from the mono microphone you will notice it from the recording – so position is involved, and I can say that there is some position information. It will sound different that if you just fade it down. It is in this sense I often read people referring to learning – you have to experience it once with the real, of being though to notice it. BTW, IMHO, directional and positional is not the same thing, although I often see it used indifferently in this thread. Is this the confusion?

I don't think so. Both directional and positional imply the preservation of a position or the ability to notice what direction the sound came from. A Mic cannot do that. But of course, it can hear distance by virtue of frequency response changes as distance increases, and reverberations from walls, floor and ceiling, which also increase with distance. But heard by a mic, these reverberations from all directions are lump summed to no direction. So the amount of reverberation actually heard is actually higher -- or exaggerated as the sum of all directions.

Do you consider that stereo depth is non existent? That the different intensities do not also play a role in stereo?

Stereo width and depth are very real, but they are both based on the time/distance relationship between two mics placed laterally. The position of the mics and the matching position of the speakers (also placed laterally) are what recreates the left to right width and depth. But remember that everything the mic 'hears' is as if it came from only one direction since all sound regardless of direction from each microphone is heard as if from one direction, flat, monophonic. It's only when you can project with two speakers the time and amplitude differences that exist between the two microphones that you create the sound stage illusion, width, depth and all.

Now, to the microphone if a source of a sound in between the mics is equal but say 10' away, it will be centered and with distance observed in the sound stage. But if the sound in between the mics is 10' away but vertical, it will have slightly different reverberation characteristics, but will still appear in the same position (centered) in the sound stage projected by the speakers.

So, you can notice left/right movement between two mics that are placed laterally, but since all directionality is summed by the microphone you cannot hear any other direction, only subtle changes in reverberation (since the mics are now summing reverberation information a little differently) still as heard as a left/right source between the mics.

--Bill

 

[Phelonious Ponk]

if one microphone can provide a sense of height, then one microphone with one speaker ought to provide a sense of lateral placement too? Right? So, why do we need two-ch stereo? To repeat bblue question?

Exactly. If what some people here are saying is true - they're hearing a realistic vertical image with sound sources properly placed in the vertical field - all we need is mono.

Tim

 

[treitz3]

Bob,

I love Sean's Forum name: Science in the Service of Art. Yeah your propensity for extemporaneous poetry can be a bit scary sometimes LOL, but I do appreciate that you always factor in the human element. The obsession with metrics is as big a problem as the obsession with absolute relativism (how's that for an oxymoron! ). For many the explanation has become more important than that being explained!

Guy 1: Oh you can't have image height because there is no height speaker.

Guy 2: But do you hear height?

Guy 1: No because it is technically impossible, I don't hear it but I perceive it.

Tell me this isn't one ludicrous conversation!

Good morning, Jack. I don't think it's a ludicrous conversation at all. Pages and pages back, I honestly thought I had caught Bill with his britches down when he listened to the Chesky CD that clearly offered the perception of height, even though it had been stated that a stereo recording, along with the stereo playback system, could not produce height. Height was exactly what I heard and it is exactly what he heard.

Yes, we both heard a perceived height and it was undeniable. Part of what has been said in this extremely long thread is that in a typical stereo recording and a stereo playback system is that height information is not recorded or played back. Phase manipulation, frequency boosting, panning and a slew of other "parlor tricks" can achieve the illusion of height. Then, certain speakers can add other aspects of perceived height by the angle or placement of particular drivers that may place a perceived kick drum at or near the floor along with a guitarist at a perceived middle height, with the cymbal being placed at a perceived higher height. This can be due to driver placement with some speakers, tweeters on top, mids in the middle and bass on the bottom. Then there are the room reflections and interactions that can further offer the illusion of height.

All of these factors and more combine to offer the illusion of height and are completely separate from the recording and playback system capturing and being able to actually playback the height information from the original venue.

 

[Steve williams]

Just waking up and finding this thread to be like the Duracell bunny. It just keeps on going.

To me Tom's summary from above might be a good place to stop unless you guys feel that there is merit in discussing the same things

 

[Phelonious Ponk]

I think the case bore repetition, in different ways, from different voices. And I think all of that served the discussion well. But at this point, I believe all who understand the case being made have probably embraced the realities while continuing to enjoy the illusions. I'm good with it being done, if every one else is.

Tim

 

[mep]

NOt thjat I see a problem with some recordings giving the illusion of more height than others and I have experienced that myself as has everyone but that only can occur with two channels and being open to the power of the illusion.

In summary, it takes a stereo pair, and a recording with some tricks if you will, to give more of an illusion of height than a recording without those tricks. But always an aillusion and alwaysf from a pair of speakers. That chesky test dics, take away one channel and the height trick disappears. BUt certainly, a speaker itself, is incapable of creating height information.

I wanted to quote the above two things from Tom because I agree with both things he said. I listened to a bunch of different music last night and each recording sets its own height. It is not a function of the speakers that creates the illusion, they just have to get out of the way. If it was solely caused by the speakers, each recording would have the exact same height and they clearly don’t.

The bottom line is that whatever manipulations occur when the music is mixed and mastered down to two channels, height information is encoded during the process. Your speakers don’t grow two feet taller for one recording and then shrink down two feet for another. The differences in height among recordings can vary widely.

This thread has basically been the Bill and Tim show where they reinforce each other and lecture everyone with their combined vast body of recording knowledge and how our stereo systems work. The problem is, everything that I have quoted from Bill below is dead wrong. The information that tricks us into hearing height in our soundstage is encoded in the recording.

Roger, there is no information recorded in two channel that can cause a phase coherent speaker system to produce the effect of height. If you have added speakers of unknown uniformity and directionality, or are utilizing room acoustics to create an image of height, fine. But it's not originating from the source, because it can't.--Bill

So if you're hearing height during playback:

1. Your ears could be (mis)interpreting the out of phase signal as height,
2. Your speakers are misaligned or positioned incorrectly,
3. It's a room artifact based on where/how you and the speakers are situated.
--Bill

And they don't produce height based on information in the recording either. To my point, they would be far less inclined to do so because there are no (or minimal) crossovers. Just room interaction and listener interpretation.

--Bill

And that is why this thread has been so confusing and contradictory. It’s there. It’s not there. You can hear it, but it doesn’t really exist. It’s your speakers being funky. It’s your room. It can’t be the speakers, it’s in the recording. It’s all phase manipulation. Blah, blah, and blah.

The real truth is that by whatever means it was encoded, each recording sets its own “height” and it varies from one recording to another how much height you have. So stick that in your non-vertical pipe and smoke it.

 

[RogerD]

And the size of the sound stage height is probably more dependent on the preamplifier that you are using.

 

[andromedaaudio]

Yep ,and what about the type of serial tweetercaps one is using in the LS filter , put some mkt s in and one is just left with some blur in the middle

And the size of the sound stage height is probably more dependent on the preamplifier that you are using.

 

[microstrip]

I don't think so. Both directional and positional imply the preservation of a position or the ability to notice what direction the sound came from. A Mic cannot do that. But of course, it can hear distance by virtue of frequency response changes as distance increases, and reverberations from walls, floor and ceiling, which also increase with distance. But heard by a mic, these reverberations from all directions are lump summed to no direction. So the amount of reverberation actually heard is actually higher -- or exaggerated as the sum of all directions. --Bill

Bill,

Your answer still mixes directional and positional. The point being debated is positional. You can perceive changes in position independently of having a clear idea of the direction. Once you have a cue that the position changes the listener processing capability will also help to fill the unknowns. And it is here that the perceptual people studies enter. What can we perceive from these little changes in reverberation and frequency response?

BTW, I can see why the sound recording industry was never interested in these effects – they are too much equipment and listener dependent. But some recordings seem to have clues enough to trigger a systematic acceptable height illusion under some conditions.

Can I suggest that those who claim that height is only a tweeter height effect can easily invert the position of their speakers, or simply turn the speaker 90 degrees keeping the tweeter at the same height and find that the drum set does not turn down? Or just listen to a properly set up Quad ESL63 – a point source speaker.

Although we are not robots, people should read what researchers studying localization of sound sources in robotics can do with a single cheap microphone and processing. Some of their software tries to emulate the way humans localize sound sources - and they study and refer to the psychoacoustics papers.

Curious that the WBF spellchecker always marks the word psychoacoustics as an error. A signal of the forum official trend?

 

[microstrip]

Just waking up and finding this thread to be like the Duracell bunny. It just keeps on going.

Steve,
It is a characteristic of these times - we run this thread on rechargeable batteries. Some people seem to have two sets of batteries!

 

[andromedaaudio]

Microstrip , i think i read on the net youre selling the maxx 3 s , whats next??

 

[JackD201]

You're missing the point. I'm not saying position is only contingent on arrival time and I agree with most of what you said above. What prevents these elements from becoming "height information" is the lack of anything in the recording or playback systems, to differentiate them. Is it distant? Sure, got that. Is it off-axis? A lot less likely that there's anything there given the way most microphones work, but I'll give you the point for the sake of argument.

Now you have the signal captured. The recording has picked up a tone from a cello that is X% reflected sound, at X volume, with X FR alterations relative to the close, direct sound. It sounds as if it is "X distant."

X distant where is the question. Up? Down? Out? Back? Left? Right? With one mic, one channel, one speaker there is nothing to differentiate up from down. You have lateral information because you have lateral channels. In the vertical plane your system is mono. So if, in the vertical plane, you hear the standing singer's voice a couple of feet above the seated player's cello, it is because that's where you expect it to be (not that there's anything wrong with that), not because of anything in the recording or the playback system.

Another possibility is that you're sitting too close to a tall driver array that is failing to cohere before it reaches your ears. Of course then, if the cellist plays a high enough note, it will suddenly jump up and join the singer. It's a bit alarming that some audiophiles consider this a quality of better speakers.

And one more time, before I'm misinterpreted again: None of this has anything to do with a "sense" of height, or with speakers projecting a sound stage taller (and wider) than their boxes. All of that happens. Even in my modest system. What it has to do with is the ability of stereo to create a differentiated and even partially accurate vertical image, similar to the horizontal image it creates with its two lateral channels. Stereo does not do this. It cannot do this. You can only place these vertical elements in that plane with your mind.

Tim

Tim, even if we confine the said images to within the tops of the cabinets and within the outer walls of the cabinets, images within these have a vertical dimension. There's a size to an image. We don't even have to discuss this. Propagation properties of a pair of loudspeakers and their acoustic setting being constant, the signal is the only differentiator for the sense of height and the occasional sense of vertical motion as well. All I ever said was "sense of height" anyway with vertical motion thrown in. Half of this has been conceded.

I'm outta here.

 

[microstrip]

Microstrip , i think i read on the net youre selling the maxx 3 s , whats next??

Top secret until the maxx3 leave.
But today, to show I take this thread seriously I am re-listening to ESL63.

 

[andromedaaudio]

 

[mep]

One byproduct of the internet is that we now have “instant geniuses.” And by that I mean we have people who have no real fundamental knowledge of a subject who turn to a search engine and read a few articles and they instantly become an “expert” on a topic they knew nothing about.

 

[microstrip]

One byproduct of the internet is that we now have “instant geniuses.” And by that I mean we have people who have no real fundamental knowledge of a subject who turn to a search engine and read a few articles and they instantly become an “expert” on a topic they knew nothing about.

It is why I prefer to read the paper versions and take notes in the library - this way I am screened by a force field from these irate postings!

Anyway, it is a small price for the huge benefit of having large amounts of knowledge accessible at a keystroke.

The main drawbacks is that many people ignore tens of years of research just because it is not in the internet, and most of them do not know how to carry proper research in the internet. Dropping the time consuming useless and unreliable information without discarding the good one needs some knowledge and technique. Just google is not enough.

 

[fas42]

BTW, I can see why the sound recording industry was never interested in these effects – they are too much equipment and listener dependent. But some recordings seem to have clues enough to trigger a systematic acceptable height illusion under some conditions.

This is the heart of the matter, and why the people with audio industry connections are beating a certain drum. Unless something in audio works on a cheap, mid-fi setup then as far as the industry is concerned it's useless, and to be disregarded. Hence the emphasis on equipment features which doesn't subtlely improve elements of sound, but rams it down your throat. Why add a touch of salt when you can empty the whole container on the chips: there, that's salty!

Qualities of playback which are a function of the intrinsic, and subtle, high quality of equipment are of no interest whatsoever to manufacturers of mass market gear. That's why the audiophile world is full of wackiness: the people in it know there is sopmething that can be achieved, but they haven't the knowledge, experience or sophisticated test equipment to research it properly. All of the latter belong to companies whose only interest is high profit, and relative mediocrity. The mantra is, follow the money ...

Frank