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I worship at the altar of imaging

hvbias

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I am reluctant to admit this, but I will; praise be, hare hare, amen to imaging :eek: One of those most audiophile-iest of things that sucks me in. So I'm not completely playing the 'phool, it does lend to my overall enjoyment as a music listener with my favorite genres, for instance being able to pin point the violin soloing while the rest of the orchestra plays quietly can be quite powerful on the right piece.

I often read about "minimum baffle diffraction" and that may or may not be helpful as a starting point for someone designing speakers but it does not tell us much measurement wise or how we can advance our knowledge further. Linkwitz has some good reading here and here.

I thought maybe I could correlate something with off axis response. Then I went back to thinking about the speakers that imaged particularly well and well... their off axis response is all over the place.

What contributes to imaging? How do we measure it?
 

fas42

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What contributes to imaging? How do we measure it?
IME, low distortion. System with ordinary speakers, in average condition - no worthwhile "imaging"; same system, tuned to the nines - "phantom" images dominate, speakers disappear. The speakers haven't changed in their characteristics, but they're being fed with a much, much cleaner signal, low level detail is there in spades with little accompanying system generated mush - and our brains have no trouble "seeing" the images that the microphones saw. This is ASA in action ...

How to measure it? Subjectively, dead easy, you either have excellent imaging or you don't; objectively, more sophisticated forms of distortion measuring, of the output from the speaker drivers, than are currently used.
 

NorthSky

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By judicious speaker positioning, by having two speakers with very tight tolerance in frequency response, by proper balance level, and by the right triangle (speakers and listeners). And, good music recordings.

Brief, with quality designed loudspeakers properly positioned. ...Good on and off axis response.

That's only a thought, mine thought.
_______

http://audiophilereview.com/reference-speakers/on-imaging-and-loudspeakers.html
http://www.gcaudio.com/resources/howtos/speakerplacement.html
 

Keith_W

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The IACC - Interaural Cross Correlation Coefficient, the Haas effect, and the step response.

The Haas effect states that sounds arriving at the ear within the first 10ms is perceived as coming from the primary. Anything later is perceived as a reflection.

The step response determines if the sounds arriving at the ear across the frequency range are arriving at the same time or not, i.e. whether it is time coherent. If it doesn't, it is perceived as smeared.

The IACC is a measure of the correlation of sounds arriving at both ears. This encompasses a whole grab bag of things which may contribute - your speaker positioning, your speaker's off axis response, your room, presence of room treatment, room size, phase rotation, and so on.
 

Cosmik

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I think imaging is just a natural by-product of solid, repeatable matching between the two speakers, and this means maintaining the match even when the speakers are required to reproduce widely differing signals. (I was listening to a track by the Small Faces where the peculiar 1960s panning placed vocals in the middle and all the bass at the right hand side. For certain types of speaker, intermodulation effects would affect a centrally-panned vocal on one side more than the other, thereby destroying the imaging of the vocal).

Low distortion (as stated by fas42) is therefore essential, as is solid time domain response. Off-axis response is not a major factor in this, nor is cabinet diffraction. It is my guess that diffraction and reflections in the room are very much secondary factors because we hear the direct sound primarily and filter out any delay-based effects - and diffraction is a delay-based effect. Absolute time domain performance of the speakers is a refinement that removes colouration of transients and must be beneficial in setting the ears 'at ease', but, again, is a secondary effect with respect to imaging. With DSP speakers, I have never found speaker positioning to be overly critical in maintaining the imaging effect - the brain seems to compensate for a simple, fixed delay.

I don't see why imaging should be regarded as mysterious in any way, as it is a by-product of decent, basic performance. It is trivial and automatic for three-way speakers with precisely-matched active crossovers to achieve it. The most accurately-matched crossovers are achieved with DSP.

Maybe the myth of imaging being a magical property has grown up around earlier technologies where the matching between speakers is upset by intermodulation distortion, poor damping, and poorly-matched crossovers whose effectiveness varies with volume. The usual suite of speaker measurements ignore these effects completely, so a mythology grows up around speakers that supposedly measure brilliantly and yet image poorly, or speakers (as stated in the OP) that measure poorly but image well.

Imaging should surely be the central aim of stereo (should the recording be created that way), but in the topsy turvy, archaic world of audio technology it is regarded by many as a mysterious property, if not a myth!
 
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Phelonious Ponk

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Good active monitors in a near-field configuration. Imaging doesn't get any better.

Tim
 

TBone

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... it does lend to my overall enjoyment as a music listener with my favorite genres, for instance being able to pin point the violin soloing while the rest of the orchestra plays quietly can be quite powerful on the right piece.

Past obvious room & speaker dependencies towards throwing an image, a systems ability to remain transparent, especially during the most complex passages, is often source driven (at least in my system).
 

Fitzcaraldo215

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I think "imaging" is quite complex, and there is also the question of how it is defined. I suspect most would agree that it is about more than just left, center, right and points in between. Most systems of any quality can deliver that with ease, like my car stereo. Also, most audio system performance measurements are done in mono or one channel at a time, whereas imaging is about our binaural hearing and the processing performed in our hearing neurological system.

But, what about apparent stage depth, front to back "layering", the apparent relative size of instruments plus their apparent 3D-ness in the soundstage? Those may be crazy and mythical audiophile nuances, perhaps. But, I believe I hear them frequently on better recordings, though not always to a satisfying degree on some. Being a classical music guy primarily, there are quite a few recordings that deliver this compared to others. I do not hear those nuances for the most part in studio recordings in pop or jazz genres with their one or more mike per performer mix downs from the relatively dead studio reverberant environment. That and other miking, mixing and mastering differences between genres I think explain this fairly well.

I think the recording itself has one hell of a lot to do with it. Yes, playback system, room and setup differences can also play a major role. I think everybody knows how speaker toe-in, for example, can affect imaging, though not much in the left, center, right sense - a wider or narrower, more intimate soundstage, etc., perhaps.

From my experience over many decades to now, the very best imagining by far is delivered by discretely recorded hi rez multichannel. The discretely recorded center channel anchors, defines and provides depth and body to the center of the soundstage in a way that two front speakers alone cannot.

Couple that with the surround channels, and you have something that has superior imaging, depth, dimensionality, etc. to any stereo I have ever heard at any price. The surrounds bring the reflected energy in the hall to you in a way stereo cannot, i.e., from 360 degrees via phantom imaging between the speakers. The sound from surround channels also interacts with front and center channels to "pull" the image forward part way out into the room, creating a better sense of soundstage depth and dimensionality.

At best, Mch creates an immersive "you are there" rather than a "they are here" kind of image, the latter of which stereo seems oriented to. But, for classical music, at least, "they are here" is an implausible image - a symphony orchestra in my listening room? In addition, stereo just cannot adequately capture the tonal warmth or the sense of space and the perception of performers with it that complex, omnidirectional hall reflections and reverberations provide live.

It is, I am sure, even more complex than that. But, in a nutshell, the imaging superiority of Mch was a huge revelation for me. It is much closer to what I hear at a live concert by quite a bit. That has totally captivated me for nearly a decade now. I listen to little in stereo and I do not find much worthwhile advantage in simulated, artificial Mch.
 

Sal1950

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I am reluctant to admit this, but I will; praise be, hare hare, amen to imaging :eek: One of those most audiophile-iest of things that sucks me in. So I'm not completely playing the 'phool, it does lend to my overall enjoyment as a music listener with my favorite genres, for instance being able to pin point the violin soloing while the rest of the orchestra plays quietly can be quite powerful on the right piece.
Imaging should surely be the central aim of stereo (should the recording be created that way), but in the topsy turvy, archaic world of audio technology it is regarded by many as a mysterious property, if not a myth!

Don't see enjoying good imaging as any part of audiophoolery. ;) It's only when some believer starts discussing how his new power cable increased the depth or the USB cable sharpened the focus that the cheese slips off the cracker. LOL
After all the whole reason for stereo is to create the image and the illusion of performers being in the listening room.
But how many people would be best served with spending the equal cost of stereo on a great mono system? I know of almost zero non stereo or HT enthusiast that have there speaker set up to produce any type of image or sit in a "sweet spot" to enjoy same? Maybe home theater has done more for a attention to speaker positioning than anything over the last 75 years. But then a good soundbar is all you really need, right? :eek:
 

NorthSky

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"In the end whether your image begins in front or behind the front plane of your speakers is FAR less important than whether your system images coherently in a three-dimensional manner, with everything in its correct place within a fully-fleshed-out three-dimensional soundstage"
 
OP
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hvbias

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Lots of good stuff, didn't expect this much traction in a day. If I didn't quote you below, I'm not ignoring you just trying to take in everything.

But, what about apparent stage depth, front to back "layering", the apparent relative size of instruments plus their apparent 3D-ness in the soundstage? Those may be crazy and mythical audiophile nuances, perhaps. But, I believe I hear them frequently on better recordings, though not always to a satisfying degree on some. Being a classical music guy primarily, there are quite a few recordings that deliver this compared to others. I do not hear those nuances for the most part in studio recordings in pop or jazz genres with their one or more mike per performer mix downs from the relatively dead studio reverberant environment. That and other miking, mixing and mastering differences between genres I think explain this fairly well.

Yes, that is stuff that should have been in my original post. I also agree with multichannel, but that is out of the question for me for anything other than home theater since the vast majority of my favorite albums and jazz/classical performances are all 2-channel (numerous jazz albums are mono only).

When I first started listening to jazz I was only interested in very well recorded music. Later on I saw past that and started listening to pre WW2 jazz which is purely mono only and often the recording quality was poor. It led me to discover some of the greatest music ever recorded. That led me down the path of delta blues. All mono only as well and some of the most powerful music I've heard.

Don't see enjoying good imaging as any part of audiophoolery. ;)

I was having a bit of fun as well hence the religious stuff, since you do often hear about audiophiles going on and on about imaging.

The IACC is a measure of the correlation of sounds arriving at both ears. This encompasses a whole grab bag of things which may contribute - your speaker positioning, your speaker's off axis response, your room, presence of room treatment, room size, phase rotation, and so on.

All great points, no doubt it is down to a multitude of factors.

Good active monitors in a near-field configuration. Imaging doesn't get any better.

Tim

While I agree that will give you sharp imaging, there are some things that I need to go along with it and perhaps I should have added this in my first post, I want exceptional imaging and excellent width and depth, not just a forward projecting razor defined sound. So in addition to excellent monitors this means plenty of space from the front and side walls. As well as linear and smooth bass response that extends deep. Additionally IME a bit more distance from the speakers than just pure near field will also help. This sort of makes the once simple premises more complex.

"In the end whether your image begins in front or behind the front plane of your speakers is FAR less important than whether your system images coherently in a three-dimensional manner, with everything in its correct place within a fully-fleshed-out three-dimensional soundstage"

Images in a 3D manner to me means it does matter whether the image begins in front or behind the speakers. I mentioned it earlier in this post in my experience having the speakers pulled far away from the front wall helps in creating that illusion, even with box speakers that are supposed to be "less sensitive" to front wall placement. Deal with the bass roll/lack of reinforcement in other ways.

Cosmik that is a well written post, let me digest this further and formulate a response.
 
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fas42

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But, what about apparent stage depth, front to back "layering", the apparent relative size of instruments plus their apparent 3D-ness in the soundstage? Those may be crazy and mythical audiophile nuances, perhaps. But, I believe I hear them frequently on better recordings, though not always to a satisfying degree on some. Being a classical music guy primarily, there are quite a few recordings that deliver this compared to others. I do not hear those nuances for the most part in studio recordings in pop or jazz genres with their one or more mike per performer mix downs from the relatively dead studio reverberant environment. That and other miking, mixing and mastering differences between genres I think explain this fairly well.
Not crazy, nor mythical. This is always encoded in the recording, but it takes a well sorted system to deliver the information cleanly enough so that the ear/brain can unravel it all. Pop recordings can often be the most rewarding, because the complexity of the acoustic spaces engineered in the mix are quite mind boggling at times - when the system is firing, there are clearly a whole array of individual spaces there, where each sound element is doing its thing, and each of those spaces can be "looked at", in turn.

What is quite remarkable is that very old mono recordings have tremendous front to back layering, because that was how they organised the volume balance of the musicians, by the physical distancing. On some swing orchestra recordings you can hear how the poor drummer was shoved right at the back of the space, so that he didn't dominate ... ;).
 
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hvbias

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What is quite remarkable is that very old mono recordings have tremendous front to back layering, because that was how they organised the volume balance of the musicians, by the physical distancing. On some swing orchestra recordings you can hear how the poor drummer was shoved right at the back of the space, so that he didn't dominate ... ;).

Yes those single mic swing era recordings with the microphone at the front of the stage certainly can pick up some room sound. A drummer who would be towards the back of the stage isn't going to have his kit picked up as loudly as the horns that were toward the front.

However it also comes down to frequency response, those mics or even the medium of a 78 wouldn't have the bass/treble fidelity we're used to today. Hence why many classical recordings of those days would have a thin midrange dominant sound.
 

fas42

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However it also comes down to frequency response, those mics or even the medium of a 78 wouldn't have the bass/treble fidelity we're used to today. Hence why many classical recordings of those days would have a thin midrange dominant sound.
Of course the fidelity is limited - which makes it remarkable that the human mind manages to compensate for these deficiencies. I have plenty of recordings which initially sounded very sorry for themselves, but at some point of improvement a system provided enough aural cues for my hearing to "fill in the gaps" - subjectively, they conveyed a full, rich listening experience; as in, I was no longer aware of the recording quality, and was solely relating to the music making, that happened at that moment.
 

NorthSky

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Phelonious Ponk

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While I agree that (near field monitors) will give you sharp imaging, there are some things that I need to go along with it and perhaps I should have added this in my first post, I want exceptional imaging and excellent width and depth, not just a forward projecting razor defined sound. So in addition to excellent monitors this means plenty of space from the front and side walls. As well as linear and smooth bass response that extends deep. Additionally IME a bit more distance from the speakers than just pure near field will also help. This sort of makes the once simple premises more complex.

Near field isn't limited that way. It's all relative; if your ears are only 3 or 4 feet from the speakers, a recording with width and depth will still reproduce that width and depth, and it can seem huge and enveloping in context. The difference is that you'll get more direct sound, less reflected sound. So you're getting more of the recording's cues for sound stage, less room. It's also easier to get more space from the front and side walls. I've set up near field configurations in the middle of rooms, allowing greater distance from bordering walls than with conventional set-ups in the same room. Again, more direct signal, less reflected. More recording, less room. Extended bass is easily addressed with sub(s). It does have its drawbacks, though - 1) It's the ultimate "sweet spot" listening mode; you'll be listening alone. 2) It throws the ratio very heavily to the recording's sound, away from the room, and you may like the room's ambience. 3) It doesn't work for very large speakers because you can very easily be too close to give the drivers room to cohere, and very tall speakers will put the highs above your head, a very odd effect. But "just a forward projecting, razor sharp sound" will not diminish any width and depth that is encoded into the recording itself.

I got much better sound stage when I was set up in the near field. I just don't listen that way anymore. I'm in a small apartment in which the living room is open to the kitchen and I like to keep the music running while I cook, clean and putter around the house. I like that, but everything else is a sonic compromise in this space.

Tim
 

Phelonious Ponk

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"Images in a 3D manner to me means it does matter whether the image begins in front or behind the speakers."

There is no real front to back depth in stereo and nothing begins behind the speakers. Nothing begins behind the speakers in surround either, for that matter. The sense of depth in stereo is a result of the recording and the mix, and the engineers' skill at creating an illusion of depth through the use of things like mic placement, the relative volumes of the instruments and the use of time-based effects.

Tim
 

FrantzM

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"Images in a 3D manner to me means it does matter whether the image begins in front or behind the speakers."

There is no real front to back depth in stereo and nothing begins behind the speakers. Nothing begins behind the speakers in surround either, for that matter. The sense of depth in stereo is a result of the recording and the mix, and the engineers' skill at creating an illusion of depth through the use of things like mic placement, the relative volumes of the instruments and the use of time-based effects.

Tim
Hi

I don't have a fixed position on imaging (Puns intended:)). At concert in large halls. I just hear a big blob of sounds with some left and right and a hall sound.... I don't hear "layered depth" and all the things we audiophiles like so much to talk about... This in concert halls. In small venues however, I have come to experience a vividness and a positioning that my ears, not my eyes do tell me... There is depth and sometimes there can be very exact positioning of players/instruments.
This said.. There is a difference between what we hear and what the speakers produce. It is somewhat true that monopole speakers radiate most of their energy to the front but sometimes with some speakers the sound does seem to come from even further back the plane of speakers. We're not talking about dipole speakers which IME perform this trick routinely. I wouldn't be so bold as to say that there isn't some sense of depth in stereo by which I believe you meant two (2) channels. In some instances regardless of how it was achieved depth can be reliably perceived, IME, in a 2-ch setting.
 
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