Talk:Octophonic sound
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Image
[edit]Two typical octophonic arrangements
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8 speakers spaced on a circle by 45°, with first speaker 0°.
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8 speakers spaced on a circle by 45°, with first speaker 22.5°.
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8 speakers spaced on the vertices of a cube.
Is this [with the circle] image worth putting in the article? Hyacinth (talk) 20:17, 21 January 2012 (UTC)
How about this one [with squares]? Hyacinth (talk) 20:45, 21 January 2012 (UTC)
And this one, rotated 22.5 degrees? Hyacinth (talk) 20:56, 21 January 2012 (UTC)
And finally the cube. Hyacinth (talk) 22:03, 21 January 2012 (UTC)
- Hi, Hyacinth. I've been trying myself to find suitable illustrations. For the three circular arrangements, although I would suppose the top of each diagram represents "front" and the bottom "back", I'm a little uncertain whether "0°" means dead ahead or dead astern. If the latter, then the third image corresponds exactly to Stockhausen's customary system for circular eight-channel sound, with station I at back half-left (22.5°) and proceeding clockwise (II = left half-back, III = left half-forward, IV = front-half-left, etc.). He did sometimes also use the positioning of the other two circle diagrams, in which case station I = centre-back, II = left-rear corner, III = left, etc. While there are 8,732 hits for "cube" on Wikimedia Commons, very few are suitable. Your suggested diagram does not have the vertices labelled. Perhaps this one, with a caption like the one I have concocted, would do:
It is a bit clumsy, having the letters in anti-clockwise order, contrary to the speaker-station numbers, and the labeled edges and diagonals are surplus to requirement. It might be better to draw a new one, where the numerals could be placed so that such a long caption might be unnecessary. On the other hand, these follow Stockhausen's usage, and while other composers may number the corners in a different order, the numeration is purely a convention, with no importance for the principle of sound distribution in a cube.—Jerome Kohl (talk) 22:39, 21 January 2012 (UTC)
- I don't get why front (ahead) or back (astern) matters, especially since the images are symmetrical and front and back are opposite. Where is the front: File:4 0 channels (quadrophonic)(quadrophonie) label.svg? I also don't see the need for labeling the speakers (electronic systems may label the tires of cars with specific computer codes but we don't need to know them to drive, and they don't seem necessary in an article about car tires or four wheel drive), but it sounds like that arises from information in a source regarding Stockhausen you have available. Hyacinth (talk) 23:37, 21 January 2012 (UTC)
- The cube you present also seems to show information relevant to the nature of cubes but not to octophony: lines d1 & d2. Hyacinth (talk) 23:50, 21 January 2012 (UTC)
- Yes, that's what I meant about "the numeration is purely a convention, with no importance for the principle of sound distribution in a cube". Although this might be relevant to an article on Octophonie or the Mittwochs-Abschied, it would only be confusing to the reader here. I also agree that the diagram from Wikimedia Commons contains irrelevant markings that would be a distraction here. I had made the suggestion before you posted your suggested cube diagram (there was an edit conflict, in fact), and I now agree it is better. Thank you.—Jerome Kohl (talk) 00:36, 22 January 2012 (UTC)
(quadrophonie)_label.svg){kind=link}
On the idea that two interlocking squares may be misleading, I present two more graphics. Hyacinth (talk) 02:28, 22 January 2012 (UTC)
- I agree that the interlocking squares may mislead the reader into supposing those squares are somehow independent of one another (e.g., one on the floor, one at the ceiling). On the one hand, at least one diagram that I have seen for eight-in-a circle speakers have done just this, presumably either in order to clarify lines of coverage, or to help with the set-up process (it is easier to "eyeball" two squares than an octagon). On balance, I would say that the octagon versions are better for the purpose of this article.—Jerome Kohl (talk) 04:02, 22 January 2012 (UTC)
Location of the listeners
[edit]It would ideal if the article could cover the location, ideal and actual, of the listeners within the octophonic space (for example, the center of a circle of speakers and all around within that circle vs. outside of that circle). For example, the images could be marked with a dot to indicate the ideal spot for listening, though then they would no longer parallel File:4 0 channels (quadrophonic)(quadrophonie) label.svg. Hyacinth (talk) 07:19, 14 February 2012 (UTC)
- Yes, easy enough with the circular arrangement, but a little trickier for the cubical one. However, instead of a dot it might be better to use a stylized head with ears (as is often done in acoustics texts, as well as music articles).—Jerome Kohl (talk) 18:09, 14 February 2012 (UTC)
- It may be noticed that unlike stereo or quadraphonic spacing, listeners may not be placed in the center, but may often vertically be on the bottom of the listening space.{{Citation needed|date=January 2012}}<!--Perfectly true, but a source is needed all the same.-->
The above text, which dealt with listener location, was removed as uncited. Hyacinth (talk) 22:50, 6 July 2012 (UTC)
- Indeed it was, and with a peculiar edit summary mentioning "sweet spots", which doesn't seem the point of the description at all. The editorial comment about needing a source despite it being a perfectly true statement, BTW, is mine. The truth is plain to anyone who has experienced Stockhausen's octophonic setup, but that constitutes Original Research.—Jerome Kohl (talk) 23:01, 6 July 2012 (UTC)
- the description makes a claim ("It may be noticed that unlike stereo or quadraphonic spacing...") regarding listening position. This infers that an idealised "sweet spot" listening location (required for successful stereo and quadrophonic imaging) is absent when using 8 channel reproduction. This is a general statement that needs to be clarified with support. It is also not the rule, there are many contrary examples. It's also the case that composers tend to sit at the centre of an 8 (or more) channel array when producing such a work, and will more often sit at a mixing desk during performance that is located centrally. Generally it is preferable to sit as close as possible to this location. In the case of ambisonic, VBAP etc. reproduction this is less the case, and with wavefield synthesis, not at all. But citations are needed for any of this information to be added. Semitransgenic talk. 01:32, 7 July 2012 (UTC)
- While I'm not going to dispute the fact that this needs a reference, I must say I still do not see where the implication of a "sweet spot" is coming from. Generally speaking, when listening to a stereo setup, the listener positions himself roughly between the two speakers; when listening to a quadraphonic setup, he places himself inside the square defined by those speakers (and not, for example, outside of the square). If this is a definition of "sweet spot", then fine. But I am astonished to learn that in a cubical octophonic setup that composers normally sit at an elevation as high above the floor as below the ceiling. My experience of this kind of setup is strictly limited to Stockhausen's practice, however. He set up one square at floor level and put the listeners inside that square in seats placed on a flat surface, where available. The remaining four speakers were set in a parallel square as high above the listeners heads as practicable, to complete the corners of the cubical space. In Osaka in 1970, the listeners were placed on a sound-permeable platform somewhat below the "equator" of the spherical space, so there, I suppose, a completely central position was being aimed for (though the sound system used many more than eight speakers). Still, a source is needed to tell us that any of this is "normal", and frankly I doubt that one can be found.—Jerome Kohl (talk) 02:49, 7 July 2012 (UTC)
- "astonished to learn that in a cubical octophonic setup that composers normally sit at an elevation as high above the floor as below the ceiling" - I think there is a misunderstanding here, this was not suggested, 8 speakers placed at audience level is by far the standard configuration for 8 channel presentations. Stockhausen's definition is the exception, but in terms of the cube configuration, i can only note that at a concert of Octophony I once attended, he sat at a console that was positioned amongst the audience, at the most central listening position - the location we generally call the "sweet spot." Semitransgenic talk. 19:16, 7 July 2012 (UTC)
- Indeed there has been a misunderstanding. The sentence in question was removed from the end of the discussion of the cubical setup, to which it obviously referred. Stockhausen indeed always insisted that his console be placed in the centre of the audience space, but not four to six meters above their heads (which would correspond to the "sweet spot" for vertical listening, if in fact our ears were arranged that way)! This was what the deleted, unreferenced sentence described. In fact, when Stockhausen was projecting quadraphonic sound (as in Kontakte) or eight-channel sound (which is what he called the circular arrangement, in opposition to the cubical "octophonic sound"), as in Sirius or Cosmic Pulses, the speakers were also mounted on stands or "flown", as high as the hall allowed, and not at the audience's ear level. In my experience, this is also the normal practice of others, though I have occasionally witnessed the ear-level arrangement.—Jerome Kohl (talk) 23:46, 7 July 2012 (UTC)
- sorry, again, to clarify : ) I didn't mean ear level placement, that would make no sense, the outer audience rows would block the sound, generally the speakers are on stands, or as you say, flown, but the so called "acoustic axis" would ideally be directed toward the audiences heads, unless a sense of the sound coming from above is the intention. Also, a cube configuration is often used for ambisonic presentations, to allow for the Z (height) channel, and Stockhausen has on occasion used it in this context. Semitransgenic talk. 22:26, 14 July 2012 (UTC)
- Why is there any doubt that, in a cubical loudspeaker array, "a sense of the sound coming from above is the intention"? In a quadraphonic setup, there may be a question of whether a "front" direction is intended, or on the contrary the listener's orientation is arbitrary (channel 1 = front left, or back left, or back right, or front right). Similarly, in an eight-channel surround setup in a single plane, track 1 may arbitrarily be established at left-front, or any other of the eight stations. (Stockhausen used left-rear as his starting point). In a cubical arrangement, there is still this uncertainty, but unless we are in a zero-gravity environment, surely there must either be a square "on the ground", or a square tilted at 45 degrees, putting one corner of the cube at the apex, and another at the nadir. This might be a novel arrangement, but I cannot imagine it being put into practice except in a spherical auditorium like the one in the German pavilion in Osaka in 1970. Even in that apex-zenith cubical arrangement, I cannot see how "a sense of the sound coming from above" cannot be part of the intention.—Jerome Kohl (talk) 06:08, 15 July 2012 (UTC)
- "Why is there any doubt that, in a cubical loudspeaker array, "a sense of the sound coming from above is the intention"?" there isn't, it usually is the intention, but speakers can be placed vertically and then positioned in such a manner that the sound is not necessarily perceived to be exclusively "coming from above." But, in the context of a cube based ambisonic presentation the idea is not simply that sound appears to be "coming from above" but that a 3-D sound "scene" is created, wherein sound appears to emanate from various locations in space as they might do in a "real" environment. Semitransgenic talk. 11:27, 15 July 2012 (UTC)
- Oh, now I see what you are saying. I was assuming you meant "some of the sound is intended to be coming from above", whereas in fact you were doubting that all (or most) of the sound is meant to be perceived in that direction. No, of course not. As I said, a sense of sound coming from above the listeners is only "part of the intention".—Jerome Kohl (talk) 18:08, 15 July 2012 (UTC)
- "Why is there any doubt that, in a cubical loudspeaker array, "a sense of the sound coming from above is the intention"?" there isn't, it usually is the intention, but speakers can be placed vertically and then positioned in such a manner that the sound is not necessarily perceived to be exclusively "coming from above." But, in the context of a cube based ambisonic presentation the idea is not simply that sound appears to be "coming from above" but that a 3-D sound "scene" is created, wherein sound appears to emanate from various locations in space as they might do in a "real" environment. Semitransgenic talk. 11:27, 15 July 2012 (UTC)
- Why is there any doubt that, in a cubical loudspeaker array, "a sense of the sound coming from above is the intention"? In a quadraphonic setup, there may be a question of whether a "front" direction is intended, or on the contrary the listener's orientation is arbitrary (channel 1 = front left, or back left, or back right, or front right). Similarly, in an eight-channel surround setup in a single plane, track 1 may arbitrarily be established at left-front, or any other of the eight stations. (Stockhausen used left-rear as his starting point). In a cubical arrangement, there is still this uncertainty, but unless we are in a zero-gravity environment, surely there must either be a square "on the ground", or a square tilted at 45 degrees, putting one corner of the cube at the apex, and another at the nadir. This might be a novel arrangement, but I cannot imagine it being put into practice except in a spherical auditorium like the one in the German pavilion in Osaka in 1970. Even in that apex-zenith cubical arrangement, I cannot see how "a sense of the sound coming from above" cannot be part of the intention.—Jerome Kohl (talk) 06:08, 15 July 2012 (UTC)
- sorry, again, to clarify : ) I didn't mean ear level placement, that would make no sense, the outer audience rows would block the sound, generally the speakers are on stands, or as you say, flown, but the so called "acoustic axis" would ideally be directed toward the audiences heads, unless a sense of the sound coming from above is the intention. Also, a cube configuration is often used for ambisonic presentations, to allow for the Z (height) channel, and Stockhausen has on occasion used it in this context. Semitransgenic talk. 22:26, 14 July 2012 (UTC)
- Indeed there has been a misunderstanding. The sentence in question was removed from the end of the discussion of the cubical setup, to which it obviously referred. Stockhausen indeed always insisted that his console be placed in the centre of the audience space, but not four to six meters above their heads (which would correspond to the "sweet spot" for vertical listening, if in fact our ears were arranged that way)! This was what the deleted, unreferenced sentence described. In fact, when Stockhausen was projecting quadraphonic sound (as in Kontakte) or eight-channel sound (which is what he called the circular arrangement, in opposition to the cubical "octophonic sound"), as in Sirius or Cosmic Pulses, the speakers were also mounted on stands or "flown", as high as the hall allowed, and not at the audience's ear level. In my experience, this is also the normal practice of others, though I have occasionally witnessed the ear-level arrangement.—Jerome Kohl (talk) 23:46, 7 July 2012 (UTC)
- "astonished to learn that in a cubical octophonic setup that composers normally sit at an elevation as high above the floor as below the ceiling" - I think there is a misunderstanding here, this was not suggested, 8 speakers placed at audience level is by far the standard configuration for 8 channel presentations. Stockhausen's definition is the exception, but in terms of the cube configuration, i can only note that at a concert of Octophony I once attended, he sat at a console that was positioned amongst the audience, at the most central listening position - the location we generally call the "sweet spot." Semitransgenic talk. 19:16, 7 July 2012 (UTC)
- While I'm not going to dispute the fact that this needs a reference, I must say I still do not see where the implication of a "sweet spot" is coming from. Generally speaking, when listening to a stereo setup, the listener positions himself roughly between the two speakers; when listening to a quadraphonic setup, he places himself inside the square defined by those speakers (and not, for example, outside of the square). If this is a definition of "sweet spot", then fine. But I am astonished to learn that in a cubical octophonic setup that composers normally sit at an elevation as high above the floor as below the ceiling. My experience of this kind of setup is strictly limited to Stockhausen's practice, however. He set up one square at floor level and put the listeners inside that square in seats placed on a flat surface, where available. The remaining four speakers were set in a parallel square as high above the listeners heads as practicable, to complete the corners of the cubical space. In Osaka in 1970, the listeners were placed on a sound-permeable platform somewhat below the "equator" of the spherical space, so there, I suppose, a completely central position was being aimed for (though the sound system used many more than eight speakers). Still, a source is needed to tell us that any of this is "normal", and frankly I doubt that one can be found.—Jerome Kohl (talk) 02:49, 7 July 2012 (UTC)
- the description makes a claim ("It may be noticed that unlike stereo or quadraphonic spacing...") regarding listening position. This infers that an idealised "sweet spot" listening location (required for successful stereo and quadrophonic imaging) is absent when using 8 channel reproduction. This is a general statement that needs to be clarified with support. It is also not the rule, there are many contrary examples. It's also the case that composers tend to sit at the centre of an 8 (or more) channel array when producing such a work, and will more often sit at a mixing desk during performance that is located centrally. Generally it is preferable to sit as close as possible to this location. In the case of ambisonic, VBAP etc. reproduction this is less the case, and with wavefield synthesis, not at all. But citations are needed for any of this information to be added. Semitransgenic talk. 01:32, 7 July 2012 (UTC)