Re: [Sursound] Catching the same fly twice (and a curious question)
Hi, I missed this discussion, being away for a short break. A BBC radio reviewer of the film 'Avatar' said that when he came out of the film into Camden High Street, it seemed, curiously, not in 3D. Film, TV and audio productions generally are not attempting to be real. Everything deemed superfluous is weeded out, creating a sort of hyper-reality. Ciao, Dave Hunt Date: Thu, 31 May 2012 19:37:14 +0200 From: J?rn Nettingsmeier netti...@stackingdwarves.net Subject: Re: [Sursound] Catching the same fly twice (and a curious question) On 05/31/2012 11:38 AM, Richard Dobson wrote: On 31/05/2012 10:03, Dave Malham wrote: .. Here, to any extent, I depart from Gibson. With sufficiently advanced technology there comes a point at which the effort required to suspend disbelief is so small as to be negligible. I was reading a report on a paper a few months ago (I think in New Scientist) where the authors were suggesting that some on-line gamers have difficult perceiving the real world as actually being real when they come out of the games. But surely that is more appropriately regarded as a pathological/delusional mental state (and very possibly a dangerous one), not a natural one representing some sort of technological nirvana. There is a world of difference between entertaining and even immersing in a fantasy as such (as in attending any Shakespeare play), and a delusion leading to possibly dysfunctional behaviour in the real world. Shall we call this the Matrix Syndrome? allow me to suspend the circling of wagons to offer a personal anecdote: there is a strategy game that involves pushing rows of black and white marbles around on (and ultimately off of) a hexagonal grid, i guess it's called abalone. when i have played this game (and staring at the round and hexagonal shapes intensely) for half an hour or so, and i look my opponent in the face, my perception of that face has changed - it looks chiselled or square-edged to me. looking at my own hands, their shape is unfamiliar and slightly unpleasant. looking around the room, i'm acutely aware of right angles all over the place and perceive them as unnatural. this effect takes at least a minute to subside. 3D movies have a similar effect on me: unless they are totally unbelievable, the skewed depth perception is accepted as normal over the course of the movie, and when i leave the cinema, the real depth perception is suddenly so remarkable that i become consciously aware of depth cues which would normally be ignored as nothing out of the ordinary. despite these pathological mental states, my functioning in the real world has not been affected (or so i'd like to believe). hence, i'm confidently resuming the circling of wagons now. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
Interesting - must be an aspect of the cocktail effect ... On 2 June 2012 04:13, umashankar mantravadi umasha...@hotmail.com wrote: as a location sound mixer, i exploited the visual reinforcement of sound in many situations. if you are recording half a dozen people speaking, and the camera focus on one - provided the sound is in synch - the person in picture will sound louder, nearer the mic, than the others. it is a surprisingly strong effect, and one side benefit is you can check for synch very quickly using it. umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar Date: Sat, 2 Jun 2012 03:09:40 +0100 From: augustineleu...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120602/051eb4c4/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
I once had a piece played atspatial audio concert and some people came to visit. Afterwards one guy came up to me and said - the sound was right there - right there in front of my face ! Was it ambionics ? Im pretty sure he just heard what he expected or hoped to hear - simply because he thought it was ambisonics and thats what he expected. I didnt get os dramatic an effect and I made it ! I think a really good related example of this sort of thing is WALLACH, H. (1940) The role of head movements and vestibular and visual cues in sound localization. Journal of Experimental Psychology, 27, 339-368. which demonstrates that visual cues can completely overide audio cues when it comes to sound localisation. Im beginning to think that people often hear what they believe they are going to hear and that the context in which you put the sounds can be as important as the filtering etc you apply to the sounds. the argument essentially says that for something to appear real it has to fit people's *pre-conception* of what is real, rather than fit what actually is real. In other words, throw out veridicality (coincidence with reality), instead try to satisfy people's belief of reality. This is an other argument for questioning the extent to which physical modelling has the capacity to create illusions of reality in sound. It is perfectly possible that a more accurate illusion is actually perceived as less real than a less accurate one. Etienne -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120601/e589e92b/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/20120602/ed042cbe/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
If lacking a anechoic chamber, substitute it with: 1 - A large field covered with about half a meter of newfallen snow. 2 - On the top ridge of a gabled barn standing in a field. 3 - In the top of a large free standing tree. Some effort and dedication is needed to replace the cash expenditure to build a anechoic room :-) - Bo-Erik -Original Message- From: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] On Behalf Of etienne deleflie Sent: den 31 maj 2012 02:28 To: Surround Sound discussion group Subject: Re: [Sursound] Catching the same fly twice (and a curious question) -- Removed text Very similar concept to Alvin Lucier's composition I am sitting in a room ... except Lucier is amplifying the effect of the room .. and it is significant... and this suggests that the experiment should be done in an anechoic chamber ... because you will be capturing not just the effect of the microphone, and the limitations in the decoding, as well as the character of the speakers, but also the character of the room. Etienne ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
On 31/05/2012 01:27, etienne deleflie wrote: .. perception. I wonder if perhaps direction is *not* that important to spatial audio. Ofcourse, it is a part, but is it central? This view leads to the questioning of the value of higher order ambisonics. I don't think people are actually allowed to do that on this list - you are definitely living dangerously! I sense the wagons circling already. Richard Dbson ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
On 30/05/2012 21:49, Eric Carmichel wrote: So how good is Ambisonics in reproducing the original auditory 'scene'? If the reconstructed wavefield is close to the original, then what happens when you record the Ambisonics system itself? Will the playback of this recording yield the same spatial information as the first recording did through an appropriate first- or n-order system? Or will the recording of the playback capture the so-called 'trickery,' thus making the recording-of-a-recording useless. Anybody tried this? I think I’ll give it a go using a four speaker arrangement (horizontal only) while playing a live recording of persons talking at eight equally-spaced locations around a Soundfield mic. Upon playback, I’ll place the Soundfield mic in the four-speaker arrangement, record this, and then listen to the recording of the recording. How much localization info do you believe will be lost? Could be fun, plus I’m a firm believer in learning by doing. Hi Eric, I have actually done this in the dim and distant past and I wasn't terribly happy with the result, iirc. Thinking about it now, I realise that the main problem was probably caused by the fact that it was a 'psychoacoustic compensated' decoder, with the shelf filters to move the decode from velocity to energy decode at a few hundred hertz, where the mkI Human Head approaches half a wavelength in size. It was also horizontal only. So, the system would only reproduce correctly over two dimensions and below a few hundred hertz. Above that it is not reproduced with exactitude - I think it was Jerome who showed this was equivalent to changing the speed of sound - someone correct me if I'm wrong - which I think would mean the correction in the Soundfield for capsule non-coincidence would be wrong. However, if a simple velocity only 3-d decode is used together with a sufficient number speakers, the reconstruction at the exact centre should be 'correct' with reducing degree of correctness as you move away from the exact centre in a way that is frequency dependent. So, at the exact centre, it should be picked up by the Soundfield as if it was the original sound field - at least up to the point where the physical extent of the Soundfield mic array means the capsule sampling points are outside the region of good reproduction. Dave -- These are my own views and may or may not be shared by my employer /*/ /* Dave Malham http://music.york.ac.uk/staff/research/dave-malham/ */ /* Music Research Centre */ /* Department of Musichttp://music.york.ac.uk/; */ /* The University of York Phone 01904 322448*/ /* Heslington Fax 01904 322450*/ /* York YO10 5DD */ /* UK 'Ambisonics - Component Imaging for Audio' */ /*http://www.york.ac.uk/inst/mustech/3d_audio/; */ /*/ ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
Dave said: Here, to any extent, I depart from Gibson. With sufficiently advanced technology there comes a point at which the effort required to suspend disbelief is so small as to be negligible. I was reading a report on a paper a few months ago (I think in New Scientist) where the authors were suggesting that some on-line gamers have difficult perceiving the real world as actually being real when they come out of the games. This suggests that even with the relatively poor systems we have at present (compared with what we know will be possible in future since it only needs evolution, not revolution, in the technology), the barrier to suspension has already become low. Now I am not suggesting that we would be able to recreate exactly a particular person's experience of going to a particular concert - at least, without Total Recall type technology (and, despite the advances with fMRI technology we are a lng way off that) - but I do think we will be able to have a pretty good shot at giving someone the experience of going to that concert themselves This is The Matrix, anything written by Philip K Dick, and before that, Plato in his Cave metaphor. It is essentially unprovable: ...If physically perfected artificial three-dimensional auditory environments were feasible, would the artificial product be as entirely realistic to perception as the real thing? If not, what ingredient is missing? If so, what would philosophically distinguish real and artificial? Is such a distinction necessary? ...Plato's metaphor for humans' grasp of reality as nothing more than shadows on a cave wall, being constrained by the limitations of what is available to sensation, is relevant today; especially for artificial environments. It is an early example of one strand of thinking about perception as mediated by sensation, inevitably a poor copy of reality. Whilst philosophers are entirely comfortable with such thought experiments, there is no obvious pragmatic way to investigate such speculations. By definition, if an artificial environment is detectable as such, then it is imperfectly executed and the hypothetical position has not been matched. On the other hand, if the artificial environment were perfectly rendered, there would be no way to prove its artificiality. [ my thesis, some years ago] So, maybe the whole point of making artificial environments is not that we can perfect them, but that, in doing so, we come to understand more about the perceptually relevant constituents of real environments. So it's the journey, not the destination..? Peter Lennox _ The University of Derby has a published policy regarding email and reserves the right to monitor email traffic. If you believe this email was sent to you in error, please notify the sender and delete this email. Please direct any concerns to info...@derby.ac.uk. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Catching the same fly twice (and a curious question)
On 31 May 2012 12:52, Peter Lennox p.len...@derby.ac.uk wrote: Actually, there is something here, though I do wonder if it is pathological. I've met people who told me that such-and-such a driving game was fantastically realistic. I found it stilted, leaden and profoundly unrealistic. I've even met people who, having 'virtually' driven a particular race track, upon actually driving it, were actually surprised that their lap performance in the real was inferior. But on the other hand, was it better or worse than if they hadn't played the game? Research has been reported showing that performance of subjects in accomplishing tasks - especially those requiring hand/eye coordination - is (significantly) better if they first work in simulations than if they hadn't done so. This is, of course, very worrying (or should be) for those who claim playing violent video games has no effect in the real world. Of course, we do make good use of training simulators for pilots, and I presume (hope) they are very much more 'realistic'. However, what they are simulating is the cockpit of an aircraft which in itself constitutes a partially mediated environment Ah - but so's a racing car... Dave -- These are my own views and may or may not be shared by my employer Dave Malham Music Research Centre Department of Music The University of York Heslington York YO10 5DD UK Phone 01904 322448 Fax 01904 322450 'Ambisonics - Component Imaging for Audio' ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] Catching the same fly twice (and a curious question)
Greetings All, I was intrigued by the post titled 'catching flies' because distance-to information is an area of interest to me. As a few folks out there know, my interest in Ambisonics (aside from music) is its application to hearing research. It is important for safety reasons that a hearing aid (HA) or cochlear implant (CI) user be able to a determine source's distance. Side note: It's interesting that a mic would be compared to the ear. No one should expect a microphone alone to do what the ear or auditory system does. A quality mic can accurately convert pressure variations to analogous voltage or current variations. That's about it. A laboratory grade mic and audio-analysis hardware or software can readily measure changes in relative phase, intensity, and frequency, and do this over a very wide dynamic range. But converting pressure variations (or particle velocity) to voltages is just the beginning of a chain of events that ultimately results in a listener’s perception of pitch, location, loudness, etc. If the goal is to reproduce a real-world sound field around the listener's head, then we need to add the following to the chain: Loudspeakers, signal processors, room acoustics, etc. Of course the mic is hugely important, and is at the heart of Ambisonics. Now back to distance approximation: I’m not sure how many readers are familiar with the book Ecological Psychoacoustics (edited by John Neuhoff). For those of you who are interested in loudness constancy, loudness of dynamically changing sounds, etc. this book addresses aspects of psychoacoustics that aren’t found in the best books on psychoacoustics (e.g. An Introduction to the Psychology of Hearing by Brian C. J. Moore). One of my mentors and an all-around great guy, William (Bill) Yost, wrote, 'The chapters in Ecological Psychoacoustics suggest many reasons why combining the rigor of psychoacoustics with the relevance of ecological perception could improve significantly the understanding of auditory perception in the world of real sound sources. Ecological Psychoacoustics provides many examples of how understanding and using information about the constraints of real-world sound sources may aid in discovering how the nervous system parses an auditory scene.' Although I don’t ascribe to a single 'school' of psychology, I do buy into James Gibson's idea that man (and animals) and their environments are inseparable (this is at the heart of Ecological Psychology). Here is where I find 'fault' or room for improvement with a lot of controlled laboratory experiments: The person (subject) is isolated from his/her environment, thus limiting the external validity of many experiments. As an example, there are ways of judging a sound source's distance that could be difficult to replicate using convention playback systems in the laboratory. It has been hypothesized that we are sensitive to the curvature (or flatness) of a wavefront, and that this shape provides cues as to distance. But when performing controlled tests of this hypothesis, free-field (anechoic) environments are limited in physical dimensions, so near-field / curved-wavefront conditions are difficult to avoid. Outside of the laboratory, reflections from surfaces are probable cues to distance. In a cafeteria (for example), the signal-to-reverb ratio grows as a talker approaches us, thus giving a viable cue as to the talker's distance. Naturally, intensity increases as well, but intensity alone isn't a great cue without a reference. A distant noise source could be equally loud but at the same time reverberant, thus compelling the listener to believe the noise source is at a distance. How well HA and CI recipients judge distance (and therefore safely avoiding disaster) is one of many questions I'm interested in. Again, I'm building a playback system designed to answer some of these questions. But if Ambisonics involves too much psychoacoustic 'trickery' (as some on the sursound list like to say), then it would not be the best recording/playback method for performing the aforementioned experiments. But to date, re-creating the sound field as it originally existed at the listener' s head via Ambisonics (while letting the ear and brain do the rest) seems to be one of the best research tools at my disposal. (Note: HRTF via headphones isn't a solution because headphones physically interfere with behind-the-ear HAs and CIs). So how good is Ambisonics in reproducing the original auditory 'scene'? If the reconstructed wavefield is close to the original, then what happens when you record the Ambisonics system itself? Will the playback of this recording yield the same spatial information as the first recording did through an appropriate first- or n-order system? Or will the recording of the playback capture the so-called 'trickery,' thus making the recording-of-a-recording useless. Anybody tried this? I think I’ll give it a go using a four
Re: [Sursound] Catching the same fly twice (and a curious question)
Although I don’t ascribe to a single 'school' of psychology, I do buy into James Gibson's idea that man (and animals) and their environments are inseparable (this is at the heart of Ecological Psychology). I think (or at least hope) that James Gibson's ideas are slowly making their way into the field of audio engineering. What I like about Gibson's ideas is that they remove the emphasis on physical modelling. For example, the perception of how far away a fly is significantly determined by what _other_ sounds exist at the same time. For example, a fly always has low loudness. If one can hear a fly very clearly and the environmental sound levels are high ... then something rings wrong. But it is not just the relative loudness ... it is also the entire acoustic ecology ... ecological consistency etc. An other aspect of Gibson's ideas that are interesting concerns the difference between mediated environments and non-mediated environments. Gibson argues that it is impossible for a mediated environment to ever be confused with a non-mediated environment... no matter how good the technology. The reasons are environmental again. Ofcourse, that doesn't mean that there cant be a 'suspension of disbelief' ... but some argue that the suspension of disbelief is the domain of art, not science. It is the expression (of the art) that fools the perception (not the stimuli). Here is where I find 'fault' or room for improvement with a lot of controlled laboratory experiments: this has been argued by a few researchers. Personally, I am starting to question that the centrality of 'direction', not just evident in audio synthesis interfaces but also evident in the underlying theory of ambisonics (and in Gerzon's ideas), is not actually just a direct result of the limitations of a laboratory based scientific understanding of sound perception. I wonder if perhaps direction is *not* that important to spatial audio. Ofcourse, it is a part, but is it central? This view leads to the questioning of the value of higher order ambisonics. Anybody tried this? I think I’ll give it a go using a four speaker arrangement (horizontal only) while playing a live recording of persons talking at eight equally-spaced locations around a Soundfield mic. Upon playback, I’ll place the Soundfield mic in the four-speaker arrangement, record this, and then listen to the recording of the recording. How much localization info do you believe will be lost? Could be fun, plus I’m a firm believer in learning by doing. would be interesting to do it over and over again .. effectively doing calculus on the effect (or bias) of the microphone. Very similar concept to Alvin Lucier's composition I am sitting in a room ... except Lucier is amplifying the effect of the room .. and it is significant... and this suggests that the experiment should be done in an anechoic chamber ... because you will be capturing not just the effect of the microphone, and the limitations in the decoding, as well as the character of the speakers, but also the character of the room. Etienne Thanks for reading, Eric -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120530/081156c8/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- http://etiennedeleflie.net -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20120531/6b2ced5e/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
