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#1
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Stereo Raw
STEREO RAW
This article is to answer a few misconceptions about what stereo is and then to offer some analogies to correct those misconceptions. "Stereo" is a generic term that means stereophonic, a field-type system of auditory perspective using more than one channel from microphones to playback speakers. It can be the legacy two channel system for commercial recordings or any number of extra channels for surround sound or center channel or even full peripheral, including above and below. It is reproduced by loudspeakers in a room, placed in positions which are geometrically similar to those of the instruments. Stereo is differentiated from monophonic, a single channel on loudspeaker in a room, binaural, a head-related system using a dummy head for recording and either headphones or a circuit for the speakers that can isolate the channels to the respective ears with crosstalk removal. "Monaural" would be a single channel sent to one ear on headphone, "diotic" being a single channel sent to two headphones equally. In general the suffix "phonic" means on loudspeakers and "aural" means on headphones with the exception that "binaural" can be reproduced on speakers as mentioned above, in which case the term is simply loudspeaker binaural, because the signals are still isolated to each ear at the head of the listener. The first main point is that there are a few misconceptions about what stereo is, rooted in some confusion between the head-related system of binaural and the field-type system stereophonic. Some distinguished writers still believe that stereo is a "two ears, two speakers" head-related system intended to pipe the two recorded signals to the two ears, creating an illusion of a panorama of sounds as heard by the microphones. They believe that the recorded signals contain all of the spatial information necessary to decode the original sound field by means of the binaural localization mechanisms of human hearing by phase, amplitude, timing of the cues in the recording. Some believe that the system is based on the two ears and their separation and pickup patterns, their pinnae effects, Interaural Cross Correlation (IACC), and response curves, or transfer functions. Some have stated outright that they believe that the "problem" with stereo is interaural crosstalk. I hope to show that the system (stereophonic) has nothing whatsoever to do with the human hearing mechanism, the number of ears on our heads, their separation, pinnae, or response curves. We all know how stereo lateralization works, with a summing localization between the two channels, the intensity or timing differences between channels making it possible to perceive an auditory event anywhere along a line between the speakers. With coincident miking techniques where there is no timing difference between channels the summing localization is based only on amplitude differences between channels. With some separation between pickup microphones there are both intensity and timing differences. Multi-miking techniques with spot mikes picking up various parts of the sound field and pan-potted into the mix by means of intensity can also be incorporated, either as the sole method of recording or as spot mikes for certain important instruments or the human voice for soloists or small groups. So where does this alleged confusion between binaural and stereophonic come from? It could be from the innocent presumption that the use of two speakers for playback has something to do with our having two ears, which in turn may have arisen from the Blumlein patent and method of recording with two coincident mikes. But meanwhile, at around the same time in the Bell Labs, researchers were experimenting with multiple channels and placing speakers on the repro stage similar to the positioning of the instruments and microphones used for pickup. One of their ideal but impractical methods of reproduction was called the "curtain of sound" in which a line of many microphones might record the performance and a similar line of speakers would reproduce it on another stage, or playback space. They defined binaural as a head-related system and stereophonic as a field-type system, in which the idea is to place many speakers on a sound stage and reconstruct the sound fields that existed in the original. Binaural, on the other hand, was always and only a two channel head-related system based on the human hearing mechanism and recorded with a dummy head, the idea being that the headphones would introduce to the ears the identical signals that the dummy head heard at the recording site. William Snow remarked that the binaural system brought the listener to the original performance location, whereas the stereophonic system brought the performers into our own listening rooms. Bell Labs ended up with their recommendation for a three channel system, but practical limitations caused it to be limited to the two channel system that we know today. So what is the major difference between a head-related and a field-type system? There are two fundamentally different ways to reproduce a sensory experience. You can reproduce the sensory input directly, such as with binaural, or you can reproduce the object itself, the sound fields produced by the orchestra and let the subject's own sensory apparatus pick it up in the normal way, just as it does with live sound. The sensory input system depends heavily on attempting to pick up the sounds in the same way that our own ears do, such as with the use of a dummy head shaped like our heads and with number of ears and ear spacing and pinnae as much like ours as feasible. But the stereophonic system has nothing whatsoever to do with the number of ears on our heads, the spacing between them, their pinnae effects, or their frequency response (transfer functions), and the whole recording and reproduction process can be accomplished without any knowledge or consideration of those factors - NONE. Compare it to the difference between sculpture and 3D photography. If we want to reproduce the image of an elephant, we could do it one of two ways. We could either take a 3D photograph in color and introduce both halves of the image into our eyes, or we could hire a sculptor to make a very real 3 dimensional model of an elephant, even to the point of being life sized and placed in a background such that we could walk all around it and each of us perceive it with our native vision mechanism, the whole process accomplished with NO knowledge of the human vision mechanism. In fact, all beings who can see in three dimensions etc, such as the animals or visitors from another planet, all would behold the same model in the same way as they did live, even with no knowledge of how they see, hear, or anything else, if we did the reproduction as a model of the real thing rather than a direct sensory input. I hope to show that the system of stereophonic sound depends ONLY on our knowledge and study of sound fields in rooms, and not upon knowledge of the human hearing mechanism, except for the very fortunate psychoacoustic fact of the summing localization being able to permit the simplification of the number of channels to fewer than the number of instruments being reproduced. The raw, base example for purposes of illustration would be a team of researchers wishing to begin exploring systems of auditory perspective to explore the field-type system. They go into the recording studio with a battery of microphones and multi-channel recorder. They close-mike each instrument but also including a small amount of the reverberance from the studio as would be heard near the instrument. Some instruments such as the piano or drum set might call for more than one mike to capture the extent of the drum kit or the width of the piano. On playback, we select a good sounding playback space and place the speakers, possibly selected for a radiation pattern similar to their instruments, in positions in the room that are geometrically similar to the original. We now have a "they are here" system if no reverberance was recorded, or modified a touch by the original hall sound if some was recorded. Notice also that if some was recorded, and if we use a llittle of the natural reflecting surfaces around the speakers in the same way that the original hall's walls did it, the reflected sound from instruments on the right side would reflect from the right wall of the playback room etc, but the instruments themselves would remain anchored where they belong by means of the precedence effect. In total, this "model" of the original sound would be 3 dimensional, having depth and width and appropriate ambience behind and around, and you could literally walk all around the model and hear it from various angles from anywhere in the room. This is the raw model for the stereophonic system. I would first point out that the whole process was accomplished with NO knowledge or reference to the human hearing mechanism and would be the same to all listeners, each one hearing the model with his or her own hearing system. It was recorded and reproduced with knowledge ONLY of sound fields in rooms, reconstructing them in the new space as a model of the original. I would then point out that this ideal system could be simplified down to fewerand fewer channels for a more practical system without losing too much, if we could only remember what it is that we are doing with the system and not lose sight of the fact that it is a field-type system, a literal reconstruction, or model, of the original, not a binaural system. We first reduce the number of channels to as few as two, thanks to the summing localization being able to place all of the instruments anywhere along a line between the two speakers. We can then pull the speakers out from the walls and place them with some geometrical similarity to the original left and right positions of the orchestra. Finally, we can customize the radiation patterns of the speakers to a lower direct to reflected ratio because of our closeness to the speakers, relative to our original distance from the orchestra. If we now treat the walls so that we might get some of the reflected sound from the recording bouncing from the left, center, and right walls of the listening room, we stand a chance of having the various recordings make our playback rooms take on most of the important characteristics of the original acoustics. Finally, so what? The answer is that this is a radical change in thinking about how the process works, from a two ears/ two speakers process achieved with the direct sound output from two speakers to a 3 dimensional model of a typical original sound field, a reconstruction of all aspects of the original within the listening room rather than a direct sensory input from the speakers to your ears. The paradigm to be sought is now sound fields in rooms rather than the "accuracy" of getting the signals intact from the speakers to your ears. The new model requires paying attention to the radiation patterns, room positioning, and acoustical qualities of the whole playback system. In-wall speakers, nearfield speakers, dead rooms, highly focused sound from the speakers, all must be re-examined in light of the new theory. The total acoustical situation that we are hearing when our ears are free to hear it without any attempt to isolate the channels at the ears or from the room can be described visually as the image model of the fields in the room, whether it be the original concert hall or the playback room. What we are hearing is the total acoustical situation, direct, early reflected, and late reflected reverberant sound. All of these must be reproduced, which is to say reconstructed in front of us, or else it will sound different from the original. The preferred solution would be surround sound, but in any case the sound patterns within the room must be honored and the goal changed to realism rather than accuracy. We are not "doing" accuracy with stereophonic recording, unless you want to hear the piano from underneath the lid, the singer from a foot in front of her tonsils, or the perspective from 9 feet above the head of the conductor. Rather, we are seeking realism as will be displayed in the final result by the placement of the microphones and speakers to display the sounds from a distance from us in the listening room, with signal processing or extra channels all around us, and NOT from the perspectives of any particular microphones. Gary Eickmeier |
#2
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Stereo Raw
Gary Eickmeier wrote:
This article is to answer a few misconceptions about what stereo is and then to offer some analogies to correct those misconceptions. Not. Done. You the deafest mo'fo' ever thought to design speakers. -- shut up and play your guitar * HankAlrich.Com HankandShaidriMusic.Com YouTube.Com/WalkinayMusic |
#3
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Stereo Raw
"Gary Eickmeier" skrev i en meddelelse
... STEREO RAW See my post(s) in this newsgroup November 13. Gary Eickmeier Kind regards Peter Larsen |
#4
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Stereo Raw
On 15/11/2014 04:57, Gary Eickmeier wrote:
STEREO RAW Summary :- I know more than anyone else about sound reproduction, and all you experts know nothing. Again. -- Tciao for Now! John. |
#5
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Stereo Raw
Garry,
for one thing, it all works, as it does, due hearing mechanism and the way the perception works. You do not have to know anything about it, but still. Without any attempt to isolate.... and so on ...., our ears and our brain still are .... isolating .... and so on ... It's all same BS talk from you, all over again, never showing anything. Why don't you go play with your grandchildren instead, or with a cat, buy a dog, walk it, ... whatever. Just lay off this stereophonic thing. |
#6
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Stereo Raw
I usually feel people can blab on as they like, and if i don't like it, i don't have to read it.... But this is sucking all the air out of the room in this news group...
I think the thing to do is to start another more worthwhile discussion.... But unfortunatley,i don't have a more interesting topic at hand right now. Maybe someone else does. Mark |
#7
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Stereo Raw
Luxey wrote:
Garry, for one thing, it all works, as it does, due hearing mechanism and the way = the perception works. You do not have to know anything about it, but still.= Without any attempt to isolate.... and so on ...., our ears and our brain = still are .... isolating .... and so on ...=20 I think the problem is that he doesn't believe that it actually DOES work, presumably because he has never actually heard it work. I know when I first heard it work I was staggered. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#8
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Stereo Raw
Scott Dorsey wrote:
Luxey wrote: Garry, for one thing, it all works, as it does, due hearing mechanism and the way = the perception works. You do not have to know anything about it, but still.= Without any attempt to isolate.... and so on ...., our ears and our brain = still are .... isolating .... and so on ...=20 I think the problem is that he doesn't believe that it actually DOES work, presumably because he has never actually heard it work. I know when I first heard it work I was staggered. --scott Maybe he staggers. -- shut up and play your guitar * HankAlrich.Com HankandShaidriMusic.Com YouTube.Com/WalkinayMusic |
#9
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Stereo Raw
"Scott Dorsey" wrote in message ... Luxey wrote: Garry, for one thing, it all works, as it does, due hearing mechanism and the way = the perception works. You do not have to know anything about it, but still.= Without any attempt to isolate.... and so on ...., our ears and our brain = still are .... isolating .... and so on ...=20 I think the problem is that he doesn't believe that it actually DOES work, presumably because he has never actually heard it work. I know when I first heard it work I was staggered. --scott Scott - I posted a very careful explanation of what I am saying, with examples of the various approaches and an ideal system and the simplifications that have been applied to such a system. Previously I have posted a partial history of my listening experience to systems designed and installed by their owners, such as Mark Davis, Jim Winey and Peter Walker. That's the best I can do. I am surprised that no one here can talk on the subject, or isn't interested. Gary |
#10
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Stereo Raw
On 11/17/2014 9:19 PM, Gary Eickmeier wrote:
That's the best I can do. I am surprised that no one here can talk on the subject, or isn't interested. I think nobody is interested. We're satisfied with the approaches that we know for achieving a "stereo experience." -- For a good time, visit http://mikeriversaudio.wordpress.com |
#11
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Stereo Raw
"Gary Eickmeier" wrote in message
... That's the best I can do. I am surprised that no one here can talk on the subject, or isn't interested. Pointing out your glaring inaccuracies and invalid assumptions is actually talking on the subject, even if you're unable to hear it due to your ears being occluded by the lining of your colon. |
#12
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Stereo Raw
"Gary Eickmeier" wrote in message ...
I am surprised that no one here can talk on the subject, or isn't interested. I'm a person who's more interested in understanding than knowing. Nothing you've written has ever "clicked". Nothing has provoked the "Aha!" reaction, where you see how things fit together, and how they relate to other things we know to be true (or accept as being true). Until you can provide these, you will continue to lead a one-man parade. |
#13
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Stereo Raw
Gary Eickmeier wrote:
"Scott Dorsey" wrote in message ... Luxey wrote: Garry, for one thing, it all works, as it does, due hearing mechanism and the way = the perception works. You do not have to know anything about it, but still.= Without any attempt to isolate.... and so on ...., our ears and our brain = still are .... isolating .... and so on ...=20 I think the problem is that he doesn't believe that it actually DOES work, presumably because he has never actually heard it work. I know when I first heard it work I was staggered. --scott Scott - I posted a very careful explanation of what I am saying, with examples of the various approaches and an ideal system and the simplifications that have been applied to such a system. Previously I have posted a partial history of my listening experience to systems designed and installed by their owners, such as Mark Davis, Jim Winey and Peter Walker. That's the best I can do. I am surprised that no one here can talk on the subject, or isn't interested. Gary We're too busy talking to windmills. -- shut up and play your guitar * HankAlrich.Com HankandShaidriMusic.Com YouTube.Com/WalkinayMusic |
#14
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Stereo Raw
William Sommerwerck wrote:
"Gary Eickmeier" wrote in message ... I am surprised that no one here can talk on the subject, or isn't interested. I'm a person who's more interested in understanding than knowing. Nothing you've written has ever "clicked". Nothing has provoked the "Aha!" reaction, where you see how things fit together, and how they relate to other things we know to be true (or accept as being true). I think this is a consequence of Gary's observations running counter to those of the rest of the world. The "theory" exists to explain something that nobody else sees. For all I know, it might be a good theory were the observations valid. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#15
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Stereo Raw
"William Sommerwerck" wrote in message ... "Gary Eickmeier" wrote in message ... I am surprised that no one here can talk on the subject, or isn't interested. I'm a person who's more interested in understanding than knowing. Nothing you've written has ever "clicked". Nothing has provoked the "Aha!" reaction, where you see how things fit together, and how they relate to other things we know to be true (or accept as being true). Until you can provide these, you will continue to lead a one-man parade. This is a fascinating divide. I know that you are a curious and well read person William. You have agreed that what most here think about stereo being able to communicate sounds from outside the speaker separation is not true, or else we wouldn't need Ambisonics. I am getting the impression that these folks wouldn't touch surround sound with an insulated pole. Have you read any of Mark Davis's articles on what makes speakers sound the way they do? Have you heard the differences among all of the speaker types such as direct, omni, dipole? This is not rocket science, there are easily observable reasons that the various speakers sound the way they do. The "Big Three" of radiation pattern, positioning, and acoustical qualities of the room combine to create the imaging that we hear. Is that wacko nutso to you? To anyone here? Linkwitz asked those questions of the AES. I am answering them. Does anyone know about all this? In answering those questions, about which of the Big Three characteristics of speakers are better than others, I put together some cheap prototype speakers for the blind testing and I won the first round to the surprise of everyone there. I have now had some much better versions of the speakers made and installed in my system, and they work and work well. I still need a center channel built and that is underway. Maybe I could run another series of blind tests to get some more objective evidence for a future paper. I think a lot more work could be done on this if I can just get the ideas out there. I am here to learn recording and I was just trying to communicate something very important that I have discovered about playback because of my statement that "it ain't a recording until it gets played back." If I send a recording to you, or you to me, what each of us hears will not be the same from the same recording. I am very concerned that there is no standard for playback, or that what people seem to be settling on is not the best it can be (see the Beolab 5 controversy in previous posts). Maybe there is no settling this except a listening test for preference. I should be getting the center channel speaker in a couple of months and then I believe I could win against all comers. Does anyone get down to Florida on vacation? I am in central Florida, Lakeland. Ralph Glasgal is another iconoclast like me who has designed and built his own ideas on how sound playback should be done. I would love to make it up there sometime and have him down here. Just doesn't seem to happen as time goes by. Gary |
#16
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Stereo Raw
Reading about the sound of speakers€¦
Dancing about architecture makes more sense, because you get the exercise. -- shut up and play your guitar * HankAlrich.Com HankandShaidriMusic.Com YouTube.Com/WalkinayMusic |
#17
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Stereo Raw
Gary,
what you're trying to acheive is impossible, because it is wrong in premisse, which is: magicaly, being able to percieve soundfield as a such (?), without isolating details. It is somewhat possible not to go into detail if listening is absolutely casual, if the signal is on the edge of undistracting background noise, but even then, at some point, mind will be atrcted by detail and that's it. Also, it is somewhat possible if listening under altered state of mind, but in that case even mono work quite well, let alone stereo, quadro, ... All above temporarily putting aside the fact that by effortlsly and unintentionally isolating different kind of info while listening to a recording with just a slightest interest, closing your eyes and letting your self hear it, one can actually experience the sense of "being there", in the space as recorded. However, I think it is the kind of idea, where if somebody with real resources and real knowledge would seriously work on it, I believe a plethora of, more less, usefull patents could pop out as by-products, but never it will work as you imagine it would. I promise never to discuss this again. |
#18
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Stereo Raw
"Luxey" wrote in message ... Gary, what you're trying to acheive is impossible, because it is wrong in premisse, which is: magicaly, being able to percieve soundfield as a such (?), without isolating details. It is somewhat possible not to go into detail if listening is absolutely casual, if the signal is on the edge of undistracting background noise, but even then, at some point, mind will be atrcted by detail and that's it. Also, it is somewhat possible if listening under altered state of mind, but in that case even mono work quite well, let alone stereo, quadro, ... All above temporarily putting aside the fact that by effortlsly and unintentionally isolating different kind of info while listening to a recording with just a slightest interest, closing your eyes and letting your self hear it, one can actually experience the sense of "being there", in the space as recorded. However, I think it is the kind of idea, where if somebody with real resources and real knowledge would seriously work on it, I believe a plethora of, more less, usefull patents could pop out as by-products, but never it will work as you imagine it would. I promise never to discuss this again. Well thanks Lux, but it is a pleasure to get a serious post from you, so don't stop. This phenomenon seems to be unique to stereo music reproduction, that we think we can somehow make it sound absolutely real. We don't presume that movies will fool us into thinking we are there, even 3D ones. It is an obvious reproduction through a rectangle up there. The depth and color qualities are enjoyable, but no one expects to be fooled into thinking he is right there. As for music, you are right - we can hear a piece on the car radio that certainly doesn't fool anyone into sounding like reality, but is very enjoyable and can transport us in our imagination to the mood and spirit of the lyrics etc etc. So what's up with all this realism quest anyway? I guess it is just some Holy Grail, a fantasy quest because stereo is so much better, more realistic sounding than mono, that maybe we can go all the way and be transported to the concert hall. Might also be some ad copy or articles in the subjective audio press that gets us going. I think that there are many facets of the sounds that we are recording, and that some of them can be identical to the real thing, such as loudness and frequency response. So we keep trying to go all the way with the rest of them, the main one being the spatial one. We find that oooh, yes, we can do some things there too, such as surround sound, LEDE, larger rooms So I press on and have found a few situations where the playback does indeed sound like the real thing. It is always due to capturing the sounds One of them was a magic show where the music sounded so real I thought it was a live orchestra. Turned out to be a stack of Bose 802 professiojnal speakers spreakers and |
#19
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Stereo Raw
"Gary Eickmeier" wrote in message ... "Luxey" wrote in message ... Gary, what you're trying to acheive is impossible, because it is wrong in premisse, which is: magicaly, being able to percieve soundfield as a such (?), without isolating details. It is somewhat possible not to go into detail if listening is absolutely casual, if the signal is on the edge of undistracting background noise, but even then, at some point, mind will be atrcted by detail and that's it. Also, it is somewhat possible if listening under altered state of mind, but in that case even mono work quite well, let alone stereo, quadro, ... All above temporarily putting aside the fact that by effortlsly and unintentionally isolating different kind of info while listening to a recording with just a slightest interest, closing your eyes and letting your self hear it, one can actually experience the sense of "being there", in the space as recorded. However, I think it is the kind of idea, where if somebody with real resources and real knowledge would seriously work on it, I believe a plethora of, more less, usefull patents could pop out as by-products, but never it will work as you imagine it would. I promise never to discuss this again. Well thanks Lux, but it is a pleasure to get a serious post from you, so don't stop. This phenomenon seems to be unique to stereo music reproduction, that we think we can somehow make it sound absolutely real. We don't presume that movies will fool us into thinking we are there, even 3D ones. It is an obvious reproduction through a rectangle up there. The depth and color qualities are enjoyable, but no one expects to be fooled into thinking he is right there. As for music, you are right - we can hear a piece on the car radio that certainly doesn't fool anyone into sounding like reality, but is very enjoyable and can transport us in our imagination to the mood and spirit of the lyrics etc etc. So what's up with all this realism quest anyway? I guess it is just some Holy Grail, a fantasy quest because stereo is so much better, more realistic sounding than mono, that maybe we can go all the way and be transported to the concert hall. Might also be some ad copy or articles in the subjective audio press that gets us going. I think that there are many facets of the sounds that we are recording, and that some of them can be identical to the real thing, such as loudness and frequency response. So we keep trying to go all the way with the rest of them, the main one being the spatial one. We find that oooh, yes, we can do some things there too, such as surround sound, LEDE, larger rooms So I press on and have found a few situations where the playback does indeed sound like the real thing. It is always due to capturing the sounds One of them was a magic show where the music sounded so real I thought it was a live orchestra. Turned out to be a stack of Bose 802 professiojnal speakers spreakers and the very large auditorium making it sound real. Another was in a hi fi store lobby I heard some band rockin out! It was just a pair of 901s hanging from chains in the next room, rockin and sockin. So I press on and have found that it is always an acoustical matter so that is my direction and there are a lot of questions remaining to be answered. Gary |
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