Re: [Sursound] Giving Precedence to Ambisonics
On 07/01/2013 06:47 AM, Robert Greene wrote: Embarrassing that after a century and more of recording. there are NO comprehensive demo discs of what really happens to controlled known acoustic sources. Really makes audio look like a silly subject. One hundred years--the scientific world in that time discovered quantum mechanics, relatively, nuclear energym lasers, the genetic code, the human genome--and audio is still uncertain which mike technique really reproduces the live sound. Embarrassing altogether. what is this rant about? every recordist who's at least half serious about her/his tools has made those very test recordings with various miking techniques, knows their properties quite intimately, and choses the most appropriate for each recording depending on acoustics, disposition of the instruments, and above all, taste. and there are hundreds of comprehensive demos of every conceivable stereo technique under the sun, with all kinds of source, and recording professionals have listened to them and honed their skills with them for decades. two-speaker stereo, in terms of spatial accuracy and precision, is more like a charcoal sketch than a photograph (much less a hologram) of the real thing. to claim otherwise is just witch-doctoring, and no amount of POA/UHJ sacred chicken blood is going to make this any more true. knowing this, most engineers prefer a technique which adds an additional layer of abstractness or interpretation or whatever, to convey an _idea_ through a _very_limited_ medium. it's a matter of personal preference, and ranting about this is about as useful as pointing out to picasso how a six-color inkjet would have fixed the disturbing blue tint of some of his paintings, and that the perspective is a little off... like you, i do prefer co-incident miking, but honestly, i don't see how the wide-spread preference for spread omnis can be construed as the end of scientific thinking. best, jörn -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 1 Jul 2013, at 08:12, Jörn Nettingsmeier netti...@stackingdwarves.net wrote: On 07/01/2013 06:47 AM, Robert Greene wrote: Embarrassing that after a century and more of recording. there are NO comprehensive demo discs of what really happens to controlled known acoustic sources. Really makes audio look like a silly subject. One hundred years--the scientific world in that time discovered quantum mechanics, relatively, nuclear energym lasers, the genetic code, the human genome--and audio is still uncertain which mike technique really reproduces the live sound. Embarrassing altogether. what is this rant about? every recordist who's at least half serious about her/his tools has made those very test recordings with various miking techniques, knows their properties quite intimately, and choses the most appropriate for each recording depending on acoustics, disposition of the instruments, and above all, taste. and there are hundreds of comprehensive demos of every conceivable stereo technique under the sun, with all kinds of source, and recording professionals have listened to them and honed their skills with them for decades. two-speaker stereo, in terms of spatial accuracy and precision, is more like a charcoal sketch than a photograph (much less a hologram) of the real thing. to claim otherwise is just witch-doctoring, and no amount of POA/UHJ sacred chicken blood is going to make this any more true. knowing this, most engineers prefer a technique which adds an additional layer of abstractness or interpretation or whatever, to convey an _idea_ through a _very_limited_ medium. it's a matter of personal preference, and ranting about this is about as useful as pointing out to picasso how a six-color inkjet would have fixed the disturbing blue tint of some of his paintings, and that the perspective is a little off... like you, i do prefer co-incident miking, but honestly, i don't see how the wide-spread preference for spread omnis can be construed as the end of scientific thinking. And (putting on my asbestos underwear) surely the obvious response to complaints that people don't care about precise localisation is that people don't necessarily care about precise localisation! There are many other factors at play, and since most recording is as much about an artistic result as it is about any particular notion of accuracy, those may be more important in a given case. An informed engineer can make a reasoned decision to do that, as Jörn says. S. PS on my way to Derby... best, jörn -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 1 Jul 2013, at 08:21, Paul Hodges pwh-surro...@cassland.org wrote: --On 30 June 2013 21:47 -0700 Robert Greene gre...@math.ucla.edu wrote: and audio is still uncertain which mike technique really reproduces the live sound. But you see, how ever many times it gets said (and it does), the discussions continue to ignore that fact that there are two independent aims in recording: reproduction of an original, and generation of something pleasant. An accurate recording of an indifferent acoustic will sound indifferent. The question is whether you prefer the realism of that, or the rose-tinting of something which obscures or glosses over the poor acoustic. And given that the performance that took place was worthy, which approach to reproduction will enable the listener to best appreciate it. And this will vary with the listeners preference (to an indeterminate extent trained by their knowledge of previous recordings and the extent of their experience of actually attending performances in real spaces. For my part, I acknowledge that there are many pleasant-sounding but inaccurate recordings which enable me to enjoy the music; but my interest in recording happens to be in realism and accuracy. Well put! And just to echo my last post, I think most modern recording starts from the position that the recording process can and often should be very unrealistic and unconcerned with accuracy. That certainly seems to be born out by most of the stuff that gets released these days. Even 'realistic' classical recordings are often very artificial on examination. Ducking for cover... S. Paul -- Paul Hodges ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
This whole discussion is to my mind a living illustration of why no progress to speak of ever occurs in audio. Nothing is made precise, no one does any experiments on what happens to sound like what was there, everyone just talks about what sounds nice to them or what sounds like what they think music sounds like, no one has any standardized arrangments for speaker playback, it is all just anecdotes. And of course the discussion almost entirely runs roughshod over the crucial point: that how far spaced apart the mikes are makes a huge difference. Way far apart like Mercury makes for three pools of light--anyone can hear this who listens on a playback set up that does not itself introduce a whole lot of slop. Closer together things change and in the limit one turns into coincident. But where are the basic tests: someone walking around on stage with a pink noise source so one can hear the tonal colorations of playback. Someone walking around with a clicker so one can hear how well the clicks are localized and so on. NOWHERE is where they are as far as being available to the public. Except for Boyk's recording from years ago which was good but not comprehensive. Call this science? It is more like religion. Each claims to he a prophet. the one who knows the truth and leads the way. But faith is all that is offered. And the arguments are silly. If the reverberant field makes the sound one big blob then a perfectly accurate recording will make it one big blob as well--if one records that far back./ No sensible person would see this as an argument for a mike technique that ADDS to the blobiness. AT MOST one could argue that stereo is not really what one wants anyway but just sort of spread out mono with vague ideas of where things are and that if one is going for that anyway one might as well used spaced omnis because they are tonally better or whatever. But all around, the thinking is just as fuzzy as spaced omni stereo. Embarrassing that after a century and more of recording. there are NO comprehensive demo discs of what really happens to controlled known acoustic sources. Really makes audio look like a silly subject. One hundred years--the scientific world in that time discovered quantum mechanics, relatively, nuclear energym lasers, the genetic code, the human genome--and audio is still uncertain which mike technique really reproduces the live sound. Embarrassing altogether. Robert ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 06/29/2013 07:40 AM, Dave Malham wrote: Still, this is all a continuation of a discussion I have been having with the beard Scotsman, Mike Williams, at AES conventions, over emails and in person for the last three decades without every coming to a real agreement - and we are still mates, much to my wife's surprise. :) the pleasure of discussing miking techniques with mr. williams :) i met mike at the last tonmeistertagung in köln, where my very unfortunate job was to tell him that we couldn't re-rig the speakers in precisely the 3d arrangement he wanted, just for his talk, so i went ahead and matrixed it onto an auro-3d setup. needless to say, he wasn't quite buying this idea (it was more a show or no show kind of decision), and i got a healthy dose of his microphone philosophy. while i wasn't convinced by everything he put forward, it was quite interesting nonetheless. the funniest aspect of that situation was that i found myself defending auro-3d (because that's what we had designed into that room) :-D i briefly mentioned that, if i had had my way, there would have been a HOA hemisphere in that room, and boy did i long for my asbestos underwear... -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 29 Jun 2013, at 07:40, Dave Malham wrote: On 28 June 2013 23:07, Goran Finnberg master...@telia.com wrote: It´s all a blob of washed out sound in the middle with very little directional effects at all. A very spacious effect that is totally missing when I hear the same forces recorded via coincident mic techniques All I can say is you've been listening to some very poor acoustics, then. I hear Goran's blob as well, even in great acoustics, although we might not agree about what's good acoustics :) It's very interesting that, as a classical recording engineer, I almost always end up with spaced mic setups. Perhaps it has to do with education, personal preference for certain aspects of sound quality (very multi-dimensional) or we might hear things differently. Some scientists are working on an article about this subject. It looks interesting: http://www.frontiersin.org/Auditory_Cognitive_Neuroscience/researchtopics/How_and_why_does_spatial-heari/1296 Here's a great comparison of different stereo mic setups. Around 03:40 the mics move from spaced to coincident. I personally can't imagine how anyone can find that an improvement but YMMV. http://www.youtube.com/watch?v=fguw5I6MxEo Still, this is all a continuation of a discussion I have been having with the beard Scotsman, Mike Williams, at AES conventions, over emails and in person for the last three decades without every coming to a real agreement - and we are still mates, much to my wife's surprise. There are plenty of things my wife and I don't agree about and we're still happily together. I think the same holds for recording techniques, as long as the violins come from the left. Kees de Visser Galaxy Classics ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 29 June 2013 13:21, Jörn Nettingsmeier netti...@stackingdwarves.netwrote: Jörn You have just proved conclusively that there are things which are truly high fidelity without having anything directly to do with recording. The sonic image generated in my imagination by what you wrote of your encounter with Mike was totally realistic, right down to the need for asbestos underwear... Dave :-) the pleasure of discussing miking techniques with mr. williams :) i met mike at the last tonmeistertagung in köln, where my very unfortunate job was to tell him that we couldn't re-rig the speakers in precisely the 3d arrangement he wanted, just for his talk, so i went ahead and matrixed it onto an auro-3d setup. needless to say, he wasn't quite buying this idea (it was more a show or no show kind of decision), and i got a healthy dose of his microphone philosophy. while i wasn't convinced by everything he put forward, it was quite interesting nonetheless. the funniest aspect of that situation was that i found myself defending auro-3d (because that's what we had designed into that room) :-D i briefly mentioned that, if i had had my way, there would have been a HOA hemisphere in that room, and boy did i long for my asbestos underwear... -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net __**_ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/**mailman/listinfo/sursoundhttps://mail.music.vt.edu/mailman/listinfo/sursound -- -- As of 1st October 2012, I have retired from the University. These are my own views and may or may not be shared by the University Dave Malham Honorary Fellow, Department of Music The University of York York YO10 5DD UK 'Ambisonics - Component Imaging for Audio' -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130629/6bfee65d/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
I use delays in the recording situation especially with the center mic and the lateral mics give 3ms early sound. there is 6 mc of time between left and right. thomaschen -Original Message- From: Fons Adriaensen f...@linuxaudio.org To: sursound sursound@music.vt.edu Sent: Thu, Jun 27, 2013 12:05 pm Subject: Re: [Sursound] Giving Precedence to Ambisonics On Thu, Jun 27, 2013 at 01:52:55PM -0400, Thomas Chen wrote: By adding time to the recording you can keep the edges still left and right however the center will move as you move. The center still moves, as by symmetry you can't use delays there. The edges will stay put even without delays as they are only reproduced by one speaker. Using delays to keep something fixed in between the center and the edges seems at least as unstable as using amplitude differences alone, unless the delays are so large that they will pull such sources to the edges anyway. So what is the point of using delays ? Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130628/c78f02b4/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
At 19:02 26/6/2013, Eric Carmichel wrote: I have a friend who's an advocate of the Decca Tree mic arrangement. Many of his recordings (a lot of choir and guitar) sound quite nice, Decca Trees sound nice on choirs because they do not have precise stereo imaging and thus one cannot hear individual members of the choir. This is, of course desirable. The same goes for large organs. I have used the setup for both, though for choirs I prefer a Blumlein pair in the middle and two flanking omnis. This for me achieves the best of both worlds. Since people who like Decca Trees usually like the phase effects that come with the setup, and an attempt to compensate for these by synthesizing the positions from a soundfield microphone without the attendant phasing effects would appear to be counterproductive. David ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
--On 29 June 2013 00:07 +0200 Goran Finnberg master...@telia.com wrote: And no one sitting listening to this washed out and unstable real life sterophonic image seems to think it is wrong at all. I find that ordinary people are as likely to like coincident recordings as spaced ones; indeed, so much so that several people in an unsophisticated (in audio terms) audience to whom I played (in a mid-sized hall) one of my coincident recordings the other day found it necessary to tell me that it was the most realistic recording they'd ever heard. Paul -- Paul Hodges ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On Sat, Jun 29, 2013 at 12:07:20AM +0200, Goran Finnberg wrote: ... while my ears are certainly NOT occupying the exact same spot instead they sit some distance apart and this gives my brain both amplitude AND timing information lost in the pure coicident recording systems. Whatever the advantages of spaced mic techniques may be - and I certainly don't want to question the value of your impressions - ** this argumentation is flawed **. Which is a real shame because every time it is repeated in discussions like this one, it keeps the real reasons, if any, why spaced mics may sound good from being investigated. It is flawed because your ears are still separated by the same distance when listening to a stereo pair of speakers, and this will cause ITD for off-center sources even if the mics were coincident or the signals were amplitude-panned. It doesn't explain why you'd need to generate the ITD twice [*], and even less what would be the advantage of ITD values that are orders of magnitude larger than those resulting from the distance between your ears (as produced by widely spaced mics). [*] The ITD for really lateral sources (off-stage, reverb) may be a bit smaller than the natural one and that may be a reason for using a small distance between the mics (ORTF style) to compensate. But that still doesn't provide a valid argument for widely spaced mics. Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 28 June 2013 23:07, Goran Finnberg master...@telia.com wrote: He made it crystal clear that in his opinon when mixing spaced microphones in a reverberant space no phase effects or comb filtering of any sort could be heard even when listening in mono. The reason is simple, the mics are sufficiently spaced in a very reverberant room so the sound picked up by each mic are so different that no comb filtering or phase effects will occur ever. Indeed, but only in a sufficiently reverberant space and with the mics sufficiently far away that the D/R ratio for all sound sources is sufficiently low. This may or may not reflect the effects from the best seat in the house As do I after having pressed that mono button thousand of times on location sessions using spaced recording techniques.. Decca Trees sound nice on choirs because they do not have precise stereo imaging and thus one cannot hear individual members of the choir. When I hear musical forces in real life in reverberant spaces there is none of the highly directional effects heard from actual sound recordings. Really? I mean Really??!!!. One of the greatest pleasures I get from going to a live concert is being able to hear and appreciate the directional elements in a way that even an Ambisonic system can't fully capture. I am very much in tune with Varese's comment about what got him started with dealing with spatial effects in his compositions; Probably because the hall (Salle Pleyel, Paris) happened to be over resonant...I became conscious of an entirely new effect produced by this familiar music [Beethoven’s Seventh]. I seemed to feel the music detaching itself and projecting itself in space. I became aware of a third dimension in the music. it gives a sense ofa journey into space. Edgar Varèse talking in 1936 about something he first explored in Intégrales (1925) It´s all a blob of washed out sound in the middle with very little directional effects at all. A very spacious effect that is totally missing when I hear the same forces recorded via coincident mic techniques and no wonder as two cardioids in coincident X/Y excludes totally any difference in arrival time between the capsules while my ears are certainly NOT occupying the exact same spot instead they sit some distance apart and this gives my brain both amplitude AND timing information lost in the pure coicident recording systems. And no one sitting listening to this washed out and unstable real life sterophonic image seems to think it is wrong at all. It is only those hellbent on analyzing the sound coming out of a wooden box where they are all listening to different things to their liking telling all others they are wrong in their opinons. In that regard recordings are unreal to me personally and I prefer the less precise positional result from spaced techniques. BTW, Decca engineers have always insisted to have the nickel diaphragms on their M50 mics claiming that the later plastic diphragms sounded diffuse and inexact to them. Using two KM56 in A/B omni 60 cm spacing recording choir in a highly reverberant church has the diction perfectly clear on my beryllium equipped mid/top of my mobile monitor speakers. Going to soft dome plastic dome speakers the diction becomes unclear and muddled. So to me at least this is partly due to the choice of speakers and mics and not so much a question of spaced versus coincident techniques. The SM2 being two KM56 in one shell shows the same effect as do the KM88 they all have 0.7 µM nickel diaphragms. -- Best regards, Goran Finnberg The Mastering Room AB Goteborg Sweden E-mail: master...@telia.com Learn from the mistakes of others, you can never live long enough to make them all yourself.- John Luther (\__/) (='.'=) ()_() Smurfen:RIP ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- -- As of 1st October 2012, I have retired from the University. These are my own views and may or may not be shared by the University Dave Malham Honorary Fellow, Department of Music The University of York York YO10 5DD UK 'Ambisonics - Component Imaging for Audio' -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130629/20091a01/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
Oops, clicked the send button too soon - here's the rest of my comments (continued from Varese quotation) On 28 June 2013 23:07, Goran Finnberg master...@telia.com wrote: It´s all a blob of washed out sound in the middle with very little directional effects at all. A very spacious effect that is totally missing when I hear the same forces recorded via coincident mic techniques and no wonder as two cardioids in coincident X/Y excludes totally any difference in arrival time between the capsules while my ears are certainly NOT occupying the exact same spot instead they sit some distance apart and this gives my brain both amplitude AND timing information lost in the pure coicident recording systems. All I can say is you've been listening to some very poor acoustics, then. In th late nineties I spent a few years really looking at the use of spatial elements in music, it became clear to me the composers of all sorts and ages had consciously or unconsciously been using them. Just sitting in a concert and listening to the way sounds moved between sections of the orchestra (ok, thats for DWMM, but the same is true of Japanese drumming groups, Javanese Gamelan and 2000 year old Chinese bell ensembles) was enough to convince me of that fact. The only (major) composer that could be said for certain not to want to do that went so far as to design and build a concert hall specifically to blur the orchestra in a single coherent blob (Wagner). Mind you, I'm pretty certain he would have objected if you couldn't tell where the singers' voices were coming from in the Bayreuth Festspielhaus! And no one sitting listening to this washed out and unstable real life sterophonic image seems to think it is wrong at all. No, I agree, 'wrong' is the wrong word - but, depending on the actual circumstances, badly designed might be appropriate or, at best, badly chosen :-) It is only those hellbent on analyzing the sound coming out of a wooden box where they are all listening to different things to their liking telling all others they are wrong in their opinons. No doubt, but it is also, and much more importantly, those of us who's preferred mode of recording is aimed at verisimilitude and my ears, at least, tell me that coincident techniques are far closer to what I hear in the concert hall, and Ambisonics better still, than spaced mics of whatever ilk - always assuming you can get the mics in the best position in the house. Still, this is all a continuation of a discussion I have been having with the beard Scotsman, Mike Williams, at AES conventions, over emails and in person for the last three decades without every coming to a real agreement - and we are still mates, much to my wife's surprise. Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- -- As of 1st October 2012, I have retired from the University. These are my own views and may or may not be shared by the University Dave Malham Honorary Fellow, Department of Music The University of York York YO10 5DD UK 'Ambisonics - Component Imaging for Audio' -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130629/16acc53f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 29 June 2013 00:35, Fons Adriaensen f...@linuxaudio.org wrote: It is flawed because your ears are still separated by the same distance when listening to a stereo pair of speakers, and this will cause ITD for off-center sources even if the mics were coincident or the signals were amplitude-panned. It doesn't explain why you'd need to generate the ITD twice [*], and even less what would be the advantage of ITD values that are orders of magnitude larger than those resulting from the distance between your ears (as produced by widely spaced mics). Absolutely. I really don't understand why the myth that coincident mics don't produce ITD's is still around. It is, I suppose, only 80 years ago that the famous patent of Alan Blumlein's was published, wherein it was shown how the combination of coincident mics and crosstalk around the head from stereo speakers created phase differences (=ITD's) between the ears but I thought the news might have gotten around by now :-) Dave -- As of 1st October 2012, I have retired from the University. These are my own views and may or may not be shared by the University Dave Malham Honorary Fellow, Department of Music The University of York York YO10 5DD UK 'Ambisonics - Component Imaging for Audio' -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130629/134871f9/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 06/26/2013 07:02 PM, Eric Carmichel wrote: Creating a virtual Decca Tree seems straightforward. To move the center channel, or a virtual mic *forward* would require little more than offline processing. I wonder whether anybody has tried the following: Slightly delay all channels except the signal (or feeds) that make up the forward-most (central) channel. If you do that, you are also recreating the comb filter effect :) Frankly, I've never been much of a Decca Tree fan for stereo. For LCR however (e.g. the frontal part of a 5.1 mix or anything with a dedicated center), it's quite useful. I've even used it for live sound amplification in theatres with a good center cluster. best, Jörn -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
On 06/27/2013 01:27 PM, JEFF SILBERMAN wrote: May I suggest Demonstration of Stereo Microphone Techniques, Performance Recordings #6 wherein 18 coincident, near-coincident and spaced omni (2 and 3 mic) stereo techniques are compared via a line of loudspeakers mounted at equal intervals and spanning 10 1/2 feet left-to-right. Each loudspeaker was 2 inches in diameter and the center to center spacing was 9 inches. An electronically generated tick was switched to each loudspeaker in turn starting at the center and moving full right, full left and full right again before ending in the center. The pros and cons of each technique are unmistakable... hi jeff, i think the test you're mentioning is not entirely fair, as much as i like coincident techniques. such a setup tests for localisation only, and with wide-band transients. it is quite clear that spaced techniques will lose, and their main advantage (better perceived spaciousness in stereo-only playback, and better LF response) is not even considered. miking is a trade-off. testing individual aspects won't tell us much about actual musical use. best, jörn -- Jörn Nettingsmeier Lortzingstr. 11, 45128 Essen, Tel. +49 177 7937487 Meister für Veranstaltungstechnik (Bühne/Studio) Tonmeister VDT http://stackingdwarves.net ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
I use an array which is an extented OCT array with M/S and a center and two hypercardoid mics pointed at +/- 90 degrees at aproximately 0.5 meter laterally. I have found that we have been ignoring the precedint effect in music reproduction. In the classic reproduction situation, i.e. 6 feet from each speaker and spaced 6 feet apart, you will find that the image will move to one side or the other if you move your head by as little as 6 inches. Any mixer will confirm this experience. By adding time to the recording you can keep the edges still left and right however the center will move as you move. ThomasChen -Original Message- From: Aaron Heller hel...@ai.sri.com To: Eric Carmichel e...@elcaudio.com; Surround Sound discussion group sursound@music.vt.edu Sent: Wed, Jun 26, 2013 11:06 am Subject: Re: [Sursound] Giving Precedence to Ambisonics Ron Streicher has written about using a Soundfield as the middle mic in a Decca tree http://www.wesdooley.com/pdf/Surround_Sound_Decca_Tree-urtext.pdf and Tom Chen has a system he calls B+ Format, which augments first-order B-format from a Soundfield mic with a forward ORTF pair. I've heard it on orchestral recordings at his studio in Stockton and it sharpens up the orchestra image nicely. Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US On Wed, Jun 26, 2013 at 10:02 AM, Eric Carmichel e...@elcaudio.com wrote: Greetings All, I have a friend who's an advocate of the Decca Tree mic arrangement. Many of his recordings (a lot of choir and guitar) sound quite nice, so I looked into aspects of the Decca Tree technique. For those who may not be familiar, the *traditional* Decca Tree arrangement is comprised of three spaced omnidirectional mics. A center microphone is spaced slightly forward. From what I've read thus far (Spatial Audio by Francis Rumsey, Focal Press; and selected articles in the AES Stereophonic Techniques Anthology), the slightly advanced time-of-arrival for the center mic stabilizes the central image due the precedence effect. However, the existence of the third (center) mic can result in exacerbated comb-filtering effects that can arise with spaced pairs. So, to avoid these filtering effects, bring on a Soundfield / Ambisonic mic...?? As I understand, Ambisonics already takes into consideration known psychoacoustical principles, and is why shelving is used to *optimize* ILDs and ITDs above and below 700 Hz, respectively. But as many readers may know, there are some nearly unpredictable ILD/ITD effects at approx. 1.7 kHz (for example, see Mills, 1972, Foundations of Modern Auditory Theory). Creating a virtual Decca Tree seems straightforward. To move the center channel, or a virtual mic *forward* would require little more than offline processing. I wonder whether anybody has tried the following: Slightly delay all channels except the signal (or feeds) that make up the forward-most (central) channel. Using an Ambisonic mic would eliminate combing effects. I realize a number of Ambisonic plug-ins have built-in crossed-cardiod, Blumlein, and spaced omni functions, but not sure I've seen any of them give *precedence* to the precedence effect or Decca Tree arrangement. Two-channel playback (both convention and binaural) is here to stay for a while, so optimizing Ambisonics for stereo is desirable to me. In fact, one of my favorite recordings from the late 80s was made with the band (The Cowboy Junkies) circled around a Calrec Soundfield mic. I've never heard whether the Trinity Session recording was released in a surround format, or if the mic's hardware decoder converted straight to stereo from the get go. That particular recording made me aware of the Soundfield mic, though surround sound wasn't an interest for me at that time. If anybody I had attempted the Decca Tree using an Ambisonic mic (even with addition of a separate and forward omni mic), I'd be interested in knowing what your experiences were. Many thanks for your time. Best, Eric C. (the C continues to remind readers that this post submitted by the *off-the-cuff* Eric) -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130626/535efc06/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130626/1de5eaf1/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130627/e00da90b/attachment.html
Re: [Sursound] Giving Precedence to Ambisonics
On Thu, Jun 27, 2013 at 01:52:55PM -0400, Thomas Chen wrote: By adding time to the recording you can keep the edges still left and right however the center will move as you move. The center still moves, as by symmetry you can't use delays there. The edges will stay put even without delays as they are only reproduced by one speaker. Using delays to keep something fixed in between the center and the edges seems at least as unstable as using amplitude differences alone, unless the delays are so large that they will pull such sources to the edges anyway. So what is the point of using delays ? Ciao, -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow) ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
Eric Carmichel wrote: ... Two-channel playback (both convention and binaural) is here to stay for a while, so optimizing Ambisonics for stereo is desirable to me. In fact, one of my favorite recordings from the late 80s was made with the band (The Cowboy Junkies) circled around a Calrec Soundfield mic. I've never heard whether the Trinity Session recording was released in a surround format, or if the mic's hardware decoder converted straight to stereo from the get go. The Trinity Session is CD UHJ encoded, so can be decoded to surround sound using an Ambisonic UHJ decoder. However, when you do this, the performers are (correctly) located in strange places. This suggests that the UHJ was not intended to be decoded. Instead, decode it using the Super Stereo mode. This keeps the performers at the front where they belong, while still surrounding the listener with the ambience of the Trinity Church. From memory, the recording engineer has said that the output from the Soundfield mic went straight into a UHJ encoder, and only two channels were recorded. If true, this means that the recording can not exist in B-Format. Regards, Martin -- Martin J Leese E-mail: martin.leese stanfordalumni.org Web: http://members.tripod.com/martin_leese/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
Ron Streicher has written about using a Soundfield as the middle mic in a Decca tree http://www.wesdooley.com/pdf/Surround_Sound_Decca_Tree-urtext.pdf and Tom Chen has a system he calls B+ Format, which augments first-order B-format from a Soundfield mic with a forward ORTF pair. I've heard it on orchestral recordings at his studio in Stockton and it sharpens up the orchestra image nicely. Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US On Wed, Jun 26, 2013 at 10:02 AM, Eric Carmichel e...@elcaudio.com wrote: Greetings All, I have a friend who's an advocate of the Decca Tree mic arrangement. Many of his recordings (a lot of choir and guitar) sound quite nice, so I looked into aspects of the Decca Tree technique. For those who may not be familiar, the *traditional* Decca Tree arrangement is comprised of three spaced omnidirectional mics. A center microphone is spaced slightly forward. From what I've read thus far (Spatial Audio by Francis Rumsey, Focal Press; and selected articles in the AES Stereophonic Techniques Anthology), the slightly advanced time-of-arrival for the center mic stabilizes the central image due the precedence effect. However, the existence of the third (center) mic can result in exacerbated comb-filtering effects that can arise with spaced pairs. So, to avoid these filtering effects, bring on a Soundfield / Ambisonic mic...?? As I understand, Ambisonics already takes into consideration known psychoacoustical principles, and is why shelving is used to *optimize* ILDs and ITDs above and below 700 Hz, respectively. But as many readers may know, there are some nearly unpredictable ILD/ITD effects at approx. 1.7 kHz (for example, see Mills, 1972, Foundations of Modern Auditory Theory). Creating a virtual Decca Tree seems straightforward. To move the center channel, or a virtual mic *forward* would require little more than offline processing. I wonder whether anybody has tried the following: Slightly delay all channels except the signal (or feeds) that make up the forward-most (central) channel. Using an Ambisonic mic would eliminate combing effects. I realize a number of Ambisonic plug-ins have built-in crossed-cardiod, Blumlein, and spaced omni functions, but not sure I've seen any of them give *precedence* to the precedence effect or Decca Tree arrangement. Two-channel playback (both convention and binaural) is here to stay for a while, so optimizing Ambisonics for stereo is desirable to me. In fact, one of my favorite recordings from the late 80s was made with the band (The Cowboy Junkies) circled around a Calrec Soundfield mic. I've never heard whether the Trinity Session recording was released in a surround format, or if the mic's hardware decoder converted straight to stereo from the get go. That particular recording made me aware of the Soundfield mic, though surround sound wasn't an interest for me at that time. If anybody I had attempted the Decca Tree using an Ambisonic mic (even with addition of a separate and forward omni mic), I'd be interested in knowing what your experiences were. Many thanks for your time. Best, Eric C. (the C continues to remind readers that this post submitted by the *off-the-cuff* Eric) -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130626/535efc06/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20130626/1de5eaf1/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Giving Precedence to Ambisonics
Hi Aaron, Many thanks for the link to Ron Streicher's article -- I passed the link along to my friend who is a big advocate of the Decca Tree. I've listened to demonstrations of the precedence effect, and they always involved a single sound source (such as a talker) coming from two loudspeakers. The signal to one loudspeaker was delayed, but slightly greater in level. The sound appears to come from the non-delayed speaker despite its lower SPL. I'm writing off the top of my head, but I believe level difference can be 6 dB or greater (up to 11 dB?) and the sound will still appear to come from the non-delayed speaker. What makes the Decca Tree interesting, then, is that when recording is mixed to two channels, there's a phantom (center) image that serves as the non-delayed source. In other words, both speakers (L+R) are same distance from listener, and level is the same, too, to create the central image. But keeping the image stable (as it's touted) is accomplished by virtue of the L+R signal being slightly pushed ahead (time-wise) of the extreme L or R signals. This delay is made possible by a slightly forward mic in the recording setup. Now I'm curious to use two speakers to demonstrate the precedence effect, but using the L + R signal as the delayed signal (or visa versa) and seeing whether the source will continue to have originated from the non-delayed speaker or phantom image. I know time differences are used in panning, but they're generally *weaker* than level differences. In comparison, the precedence effect isn't subtle, but it does wear off after the onset of a sound, and level becomes the dominant localization cue--at least that has been my experience. I haven't heard a single-source demo of the precedence effect that uses a phantom image as the delayed or non-delayed source--the sounds have always come from discrete speakers/locations. Thanks again for help and link. Best, Eric C. From: Aaron Heller hel...@ai.sri.com To: Eric Carmichel e...@elcaudio.com; Surround Sound discussion group sursound@music.vt.edu Sent: Wednesday, June 26, 2013 11:06 AM Subject: Re: [Sursound] Giving Precedence to Ambisonics Ron Streicher has written about using a Soundfield as the middle mic in a Decca tree http://www.wesdooley.com/pdf/Surround_Sound_Decca_Tree-urtext.pdf and Tom Chen has a system he calls B+ Format, which augments first-order B-format from a Soundfield mic with a forward ORTF pair. I've heard it on orchestral recordings at his studio in Stockton and it sharpens up the orchestra image nicely. Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US On Wed, Jun 26, 2013 at 10:02 AM, Eric Carmichel e...@elcaudio.com wrote: Greetings All, I have a friend who's an advocate of the Decca Tree mic arrangement. Many of his recordings (a lot of choir and guitar) sound quite nice, so I looked into aspects of the Decca Tree technique. For those who may not be familiar, the *traditional* Decca Tree arrangement is comprised of three spaced omnidirectional mics. A center microphone is spaced slightly forward. From what I've read thus far (Spatial Audio by Francis Rumsey, Focal Press; and selected articles in the AES Stereophonic Techniques Anthology), the slightly advanced time-of-arrival for the center mic stabilizes the central image due the precedence effect. However, the existence of the third (center) mic can result in exacerbated comb-filtering effects that can arise with spaced pairs. So, to avoid these filtering effects, bring on a Soundfield / Ambisonic mic...?? As I understand, Ambisonics already takes into consideration known psychoacoustical principles, and is why shelving is used to *optimize* ILDs and ITDs above and below 700 Hz, respectively. But as many readers may know, there are some nearly unpredictable ILD/ITD effects at approx. 1.7 kHz (for example, see Mills, 1972, Foundations of Modern Auditory Theory). Creating a virtual Decca Tree seems straightforward. To move the center channel, or a virtual mic *forward* would require little more than offline processing. I wonder whether anybody has tried the following: Slightly delay all channels except the signal (or feeds) that make up the forward-most (central) channel. Using an Ambisonic mic would eliminate combing effects. I realize a number of Ambisonic plug-ins have built-in crossed-cardiod, Blumlein, and spaced omni functions, but not sure I've seen any of them give *precedence* to the precedence effect or Decca Tree arrangement. Two-channel playback (both convention and binaural) is here to stay for a while, so optimizing Ambisonics for stereo is desirable to me. In fact, one of my favorite recordings from the late 80s was made with the band (The Cowboy Junkies) circled around a Calrec Soundfield mic. I've never heard whether the Trinity Session recording was released in a surround format, or if the mic's hardware decoder converted straight
