Re: [Sursound] Distance perception
On 2011-07-27, Fons Adriaensen wrote: This is very subjective, but yes, I have the impression it is better. Also the speakers tend to disappear as being the sources of the sound and there is less interaction from the room - the sensation that the sound is 'just there' is stronger than for straight stereo. I wonder... Has anybody tried calculating the traditional ambisonic localisation measurables for this sort of playback? For UHJ super stereo we already know what they are. But for ambisonically panned stereo? At least for Blumlein stereo it would stand to reason that we'd be getting many of the same benefits we get when going with TriField, or any of the multichannel frontal stereo setups Gerzon at al's work for HDTV compatibility stereo hinted at. Then, some of that benefit would leach onto pairwise panned, staged material as well -- it does retain phase just as coincident Blumlein does, and the main psychoacoustics happen on the decoder side, so that the only thing which really is mismatched is the encoding locus over the Scheiber sphere. With intensity panned stereo, it isn't that far off if you look at it... -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On Thu, Jul 28, 2011 at 05:30:55PM -0700, Robert Greene wrote: I am not an electronics designer but I think the causes of current limiting and voltage limiting are in effect different. Of course the one actually happens when the other happens: an amp cannot maintain voltage without maintaining current too (and vice versa). But I think the causes of limiting into high impedance and low impedance are different. Current strength(which is what gives out in this informal sense into low impedances) is attached to big power supply storage and (I think) lots of output devices paralleled , and voltage(which is what limits when the speaker impedance is high, again in this informal sense) is attached to the rail levels or the voltage limits of the output devices. Correct. Output voltage is limited by the voltage of the power supply and any voltage lost in circuit elements. If you try to go above it the signal will simply be clipped. More sophisticated amps will monitor this and stop you from driving their high power parts into saturation by limiting the input voltage. Current is limited by what the power supply can deliver, and in almost all amps is *actively* limited regardless of that to protect the amp itself, both against excessive current AND excessive internal power dissipation. For the latter, the current limiting is usually made dependent on output voltage: more current is allowed when the momentary output voltage gets higher (and voltage drop over the output devices delivering the current gets lower). This can lead to an amp having problems driving a reactive load. Very high power amps as used in PA do monitor all of this, they are well aware of the impedance they are driving and have data interfaces reporting a variety of performance data to a centralised monitoring and control application. But in all cases, as long as they are working within their normal limits, they are supposed to be voltage sources, with the resulting current being whatever it takes. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
Hang on, hang on - if the electrons exceed the speed of light then either a: their mass will go infinite and the cable will implode into a mini black hole or b: they will decay into tachyons resulting in the sound coming out of the speaker before it has even been recorded Dav M. On Jul 27 2011, David Worrall wrote: I have been browsing this list long enough to observe that this phenomena only occurs (or at least is only reported, on this list, albeit with annual regularity) in Northern Hemisphere summers. Down under, the summers are so hot that the electrons want to pass through cable as quickly as possible, so they exhibit an exact opposite characteristic: Temporal Intensification Dilation (also DIT, unfortunately); thought to be the caused as them exceeding the speed of light in order to 'get the f*** outa there'. The phenomena can be reversed, or at least alleviated from a 3rd person perspective, by plugging the cables into a live mains socket and biting hard on the other end. David On 28/07/2011, at 3:42 AM, Sampo Syreeni wrote: On 2011-07-27, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ Dr David Worrall Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Projects, Music Council of Australia worrall.avatar.com.au sonification.com.au -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110728/bffc3272/attachment.html ___ 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] Distance perception (really speaker wire discussion!)
Arghhh - I shouldn't have let this out of the bag - there's clearly a _massive_ EU research funding opportunity here - now, how do I go about obtaining time on the large Hadron Collider??? Dave M. On Jul 28 2011, dave.mal...@york.ac.uk wrote: Hang on, hang on - if the electrons exceed the speed of light then either a: their mass will go infinite and the cable will implode into a mini black hole or b: they will decay into tachyons resulting in the sound coming out of the speaker before it has even been recorded Dav M. On Jul 27 2011, David Worrall wrote: I have been browsing this list long enough to observe that this phenomena only occurs (or at least is only reported, on this list, albeit with annual regularity) in Northern Hemisphere summers. Down under, the summers are so hot that the electrons want to pass through cable as quickly as possible, so they exhibit an exact opposite characteristic: Temporal Intensification Dilation (also DIT, unfortunately); thought to be the caused as them exceeding the speed of light in order to 'get the f*** outa there'. The phenomena can be reversed, or at least alleviated from a 3rd person perspective, by plugging the cables into a live mains socket and biting hard on the other end. David On 28/07/2011, at 3:42 AM, Sampo Syreeni wrote: On 2011-07-27, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ Dr David Worrall Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Projects, Music Council of Australia worrall.avatar.com.au sonification.com.au -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110728/bffc3272/attachment.html ___ 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 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
a: in the northern hemisphere - because there are more people (masses- Kyrie Eleison!) and b: in the southern hemisphere - which is why the electroacoustic music is so 'advanced' there drw On 28/07/2011, at 4:50 PM, dave.mal...@york.ac.uk wrote: Hang on, hang on - if the electrons exceed the speed of light then either a: their mass will go infinite and the cable will implode into a mini black hole or b: they will decay into tachyons resulting in the sound coming out of the speaker before it has even been recorded Dav M. On Jul 27 2011, David Worrall wrote: I have been browsing this list long enough to observe that this phenomena only occurs (or at least is only reported, on this list, albeit with annual regularity) in Northern Hemisphere summers. Down under, the summers are so hot that the electrons want to pass through cable as quickly as possible, so they exhibit an exact opposite characteristic: Temporal Intensification Dilation (also DIT, unfortunately); thought to be the caused as them exceeding the speed of light in order to 'get the f*** outa there'. The phenomena can be reversed, or at least alleviated from a 3rd person perspective, by plugging the cables into a live mains socket and biting hard on the other end. David On 28/07/2011, at 3:42 AM, Sampo Syreeni wrote: On 2011-07-27, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ Dr David Worrall Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Projects, Music Council of Australia worrall.avatar.com.au sonification.com.au -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110728/c18b7dd9/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
certain kinds of sounds (like the hindu om, which has to produced while breathing in) or known to slow the universe down, including the electrons in loudspeaker wires - even extremely snake-y wires. the result after a time is that the electrons pool in the wire and form a bose-einstein condensate. (no i did not read about this in the wireless world). i dont like bose loudspeakers so it is not subliminal advertising either. umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar Date: Thu, 28 Jul 2011 07:57:48 +0100 From: dave.mal...@york.ac.uk To: sursound@music.vt.edu Subject: Re: [Sursound] Distance perception (really speaker wire discussion!) Arghhh - I shouldn't have let this out of the bag - there's clearly a _massive_ EU research funding opportunity here - now, how do I go about obtaining time on the large Hadron Collider??? Dave M. On Jul 28 2011, dave.mal...@york.ac.uk wrote: Hang on, hang on - if the electrons exceed the speed of light then either a: their mass will go infinite and the cable will implode into a mini black hole or b: they will decay into tachyons resulting in the sound coming out of the speaker before it has even been recorded Dav M. On Jul 27 2011, David Worrall wrote: I have been browsing this list long enough to observe that this phenomena only occurs (or at least is only reported, on this list, albeit with annual regularity) in Northern Hemisphere summers. Down under, the summers are so hot that the electrons want to pass through cable as quickly as possible, so they exhibit an exact opposite characteristic: Temporal Intensification Dilation (also DIT, unfortunately); thought to be the caused as them exceeding the speed of light in order to 'get the f*** outa there'. The phenomena can be reversed, or at least alleviated from a 3rd person perspective, by plugging the cables into a live mains socket and biting hard on the other end. David On 28/07/2011, at 3:42 AM, Sampo Syreeni wrote: On 2011-07-27, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ Dr David Worrall Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Projects, Music Council of Australia worrall.avatar.com.au sonification.com.au -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110728/bffc3272/attachment.html ___ 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 ___ 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/20110728/128da6a3/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
All of this arises in my view from two simple things: 1 People in audio do not check things double blind and 2 People in audio do not normalize things for frequency response and do not do precision measurements of frequency response. Point 1 is obvious. About point 2: Small shifts in frequency response occur for a wide variety of reasons, cables among them. If the shifts are indeed small, down near the 0.1 dB threshold(approximately), then the changes heard are not always of the overt tonal nature--brighter, more or less bass, nore or less midrange forward and so on--but are often of the nature of things like transparency and other poetic and imprecise audiophile words. So one could in fact end up hearing an improvement--or what could seem like an improvement--from changing cables, simply because there was a microshift in frequency response. No sensible person would pay a lot of money to get such a micro-shift in frequency response. But if one did not KNOW that that was what it was, I suppose a certain kind of person might be inclined to pay a lot of money for increased transparency. Words count. A trivial thing like a tiny lift around 6k can be made nontrivial to some people by giving it an impressive name, like transparency. I have heard otherwise sensible people claim that transaparency is an independent thing, outside the realm of ordinary audio measurements and phenomena. This is of course nonsense. But it is a kind of nonsense that propagates all too readily among people who do not understand at all how audio works but who have spent a lot of time listening to it. Robert On Wed, 27 Jul 2011, Danny McCarty wrote: Funny, I read the company's name as Synthetic Research. Much more appropriate. On Jul 27, 2011, at 3:35 PM, Paul Doornbusch wrote: The shock, and potentially the most snake-oil, could be from the $40,000 for these Galileo speaker cables (poor old Galileo probably does not even get any royalties from them using his esteemed name): http://www.synergisticresearch.com/galileo-system/galileo-system-speaker-cable/ reviewed here http://www.avguide.com/review/synergistic-research-galileo-cable-and-interconnect-tas-210 my brother pointed this out to me, coincidentally, on Monday. p. A few surprising shocks ought to be enough to shake the more reticent ones loose. After that, just leave the negative pole connected on the upper end, and you'll have a fresh start in the morning. The electrons will thank you too! havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ 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 Danny McCarty Monolith Media, Inc. 4183 Summit View Hood River, Or 97031 415-331-7628 541-399-0089 Cell http://www.monolithmedia.net/ http://www.danielmccarty.com/ ___ 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] Distance perception (really speaker wire discussion!)
The review comments on Amazon for the Audio Quest K2 speaker cable are very entertaining in the most: http://www.amazon.com/AudioQuest-K2-terminated-speaker-cable/product-reviews/B000J36XR2/ Certainly more interesting than some dubious pseudo-expert 'review' - Neil On 7/28/2011 1:03 PM, Robert Greene wrote: All of this arises in my view from two simple things: 1 People in audio do not check things double blind and 2 People in audio do not normalize things for frequency response and do not do precision measurements of frequency response. Point 1 is obvious. About point 2: Small shifts in frequency response occur for a wide variety of reasons, cables among them. If the shifts are indeed small, down near the 0.1 dB threshold(approximately), then the changes heard are not always of the overt tonal nature--brighter, more or less bass, nore or less midrange forward and so on--but are often of the nature of things like transparency and other poetic and imprecise audiophile words. So one could in fact end up hearing an improvement--or what could seem like an improvement--from changing cables, simply because there was a microshift in frequency response. No sensible person would pay a lot of money to get such a micro-shift in frequency response. But if one did not KNOW that that was what it was, I suppose a certain kind of person might be inclined to pay a lot of money for increased transparency. Words count. A trivial thing like a tiny lift around 6k can be made nontrivial to some people by giving it an impressive name, like transparency. I have heard otherwise sensible people claim that transaparency is an independent thing, outside the realm of ordinary audio measurements and phenomena. This is of course nonsense. But it is a kind of nonsense that propagates all too readily among people who do not understand at all how audio works but who have spent a lot of time listening to it. Robert On Wed, 27 Jul 2011, Danny McCarty wrote: Funny, I read the company's name as Synthetic Research. Much more appropriate. On Jul 27, 2011, at 3:35 PM, Paul Doornbusch wrote: The shock, and potentially the most snake-oil, could be from the $40,000 for these Galileo speaker cables (poor old Galileo probably does not even get any royalties from them using his esteemed name): http://www.synergisticresearch.com/galileo-system/galileo-system-speaker-cable/ reviewed here http://www.avguide.com/review/synergistic-research-galileo-cable-and-interconnect-tas-210 my brother pointed this out to me, coincidentally, on Monday. p. A few surprising shocks ought to be enough to shake the more reticent ones loose. After that, just leave the negative pole connected on the upper end, and you'll have a fresh start in the morning. The electrons will thank you too! havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ 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 Danny McCarty Monolith Media, Inc. 4183 Summit View Hood River, Or 97031 415-331-7628 541-399-0089 Cell http://www.monolithmedia.net/ http://www.danielmccarty.com/ ___ 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 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On Thu, Jul 28, 2011 at 10:43:33PM +0200, Justin Bennett wrote: Maybe a similar effect to the Bloomline speakers http://www.bloomline.nl/ not a very useful website if you don't speak dutch - but these speakers create a virtual image between 2 vertically positioned drivers - indeed the speakers disappear I heard a concert with amplified instruments and electronic sources and it was very impressive - or rather unimpressive because the sound seemed so natural. I think these have been discussed before on the list. The demo I heard was on a large theatre stage with speakers on the floor and hung from the lighting grid. The sound seems to come from the stage - in between. All the audio was panpotted stereo or mics in stereo pairs as far as I know. Interesting. But the website is pretty useless even if you speak dutch as I do. Until they explain how this works I'll take it with an unhealthy dose of salt. BTW, one must be either Ferengi or Dutch to turn 'Blumlein' into 'Bloomline'. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On Tue, Jul 26, 2011 at 10:26:49PM -0400, Marc Lavallée wrote: How large is the resulting stereo image? As large as you make it, see below. Is your technique documented somewhere? Can it work with a horizontal hexagon? With 2rd order AMB? Sure. There isn't much to document, just set up your AMB system and use two AMB panners for the L and R signals. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
Apart from the damping problem which has been very well laid out by Fons, there is another factor which can come into play and which I documented in an article in Hi-Fi for Pleasure many years ago. The fact is that many poorly constructed cables, when hit with a bit of power, will actually produce sound themselves. Those of us who are ancient, like me, will remember that in the days before printed circuit board construction - so things were point-to-point wired - oscilloscopes (in particular but not exclusively), were very prone to this and would often sing quite happily when hit with an audio signal. So, when I first heard the sound from the cables I though it was the scope I was using and it took me a while to realise it wasn't. The produced sound suffers from extreme variations in frequency response and is very 'hysteric', in that there is often a level below which it doesn't happen at all and over which it suddenly starts to sing. It's to long ago to quote figures, the experimental approach I used was not terrible rigorous and the whole subject needs (properly) reinvestigating but it's still something to be aware of. Fortunately, as Fons says, decent mains cable would be fine - at least it was then. The one I really liked when I was testing speaker cables was ordinary flat ribbon cable with alternate conductors paralleled up. Low resistance, low inductance, didn't produce its own noises and fitted nicely under carpets (or you could use the colour coded variety and use it as a feature in the room - not sure if it would necessarily improve the SAF, though :-) Dave On 27/07/2011 05:57, Bill de Garis wrote: On 26/07/11 3:41 p.m., Sampo Syreeni wrote: On 2011-07-26, Fons Adriaensen wrote: I certainly don't want you to waste your money on fancy speaker cables. Never thought otherwise. That's obviously never been what we do here. ;) But resistance does matter, so a good cross section such as 2.5 mm^2 puts you on the safe side. What I was trying to ask is, what's the real problem with resistance, especially with regard to a passive speaker and a modern, A/B class solid state end stage? I mean, I don't really see cable resistance shifting their operating point much, even with feedback, within the audible range. What is it that I'm missing? I swapped out some lamp cable on the speakers of a stereo setup some years back with some cheap stranded speaker cable I bought at Costco. Each core of the cable was about 3 times the cross sectional area of the lamp cord (each core of the speaker cable was about 3/16 in dia). The distances were not great, 5 or 6 feet. The improvement in stereo imaging was huge. Previously the image had wandered around between the speakers seemingly at random, now it was rock solid at the point wherever it was when I recorded it. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- 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 432448*/ /* Heslington Fax 01904 432450*/ /* 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] Distance perception
On 26 Jul 2011, at 17:00, sursound-requ...@music.vt.edu wrote: Date: Mon, 25 Jul 2011 20:18:42 -0400 From: Marc Lavall?e m...@hacklava.net After reading this difficult thread (I'm replying with a new title), I have simple questions about room sizes and speaker distances. Imagine two rooms with proper acoustic characteristics and treatments for ambisonics reproduction: the first is 3mX4m and the other is four times larger in surface (9mX12m). In both rooms there's a horizontal hexagon of speakers, and 5 speakers are against a wall. When NFC is applied in both rooms, do they sound the same in terms of distance perception when playing the same recording? Or is the same sound object appear to be twice as far in the largest room? As J?rn has pointed out, the effect of the different acoustics of the rooms is hard to eliminate, and speaker placement relative to walls and other surfaces also has audible consequences. Anechoic rooms are hard to achieve, and are rather unpleasant and disturbing to be in. It is would be difficult to do an A/B comparison. So, it is a rather hypothetical, if relevant, question. A better test would be two identical or similar outdoor rigs at different distances matched in level, with the ability to switch between them. The 40' geese phenomenon has been mentioned many times. John Leonard's recording, obviously fairly close perspective, when played on large systems gives the impression of very large geese. No-one seems to have an explanation for this. Possibly it is due to conflicting perceptual cues, visual as well as aural. Even without any visual aspect close sound sources seem 'bigger'. Aural perspective is not the same as visual perspective, though there are some similarities. Visual distance acuity is probably not much better than aural distance acuity. Both rely on comparison, experience and supposition. My hunch, which I cannot back up with formal theory, is that distance perception is relative rather than absolute. So, I would expect the two 'rooms' to sound broadly similar though not identical, assuming 'proper acoustic characteristics' and appropriate NFC. Distance perception would be consistent, though different, in each 'room'. Apart from widening the listening sweet spot, are larger rooms better at reproducing distance cues when using the same speaker configuration? It has been said several times on this list that the size of the sweet spot is related to wavelength and not the size of the speaker rig, and I'm not knowledgeable enough to disagree. Certainly larger rooms have later and lower level reflections, with lower frequency resonant nodes and a more even frequency distribution of the harmonics of those nodes. Speakers can be more easily located away from walls and corners, resulting in direct sound sound from them arriving earlier and being louder than reflected sound. Is distance perception directly related to speaker distances? I suspect that that it is related in the case of ambisonics, though not directly. This is more psychoacoustics than just physics or acoustics. Ciao, Dave Hunt ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
years ago (no decades ago) i found what a huge difference it made if the wires were reasonably thick, and cut to be exactly same length. cutting them to same length is problematic with eight loudspeakers (unless the amp sits in the sweet spot) but my next rig, in my own house, in bangalore next year, will have same length wires to all the speakers. umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar Date: Tue, 26 Jul 2011 21:57:49 -0700 From: d...@dgvo.net To: sursound@music.vt.edu Subject: Re: [Sursound] Distance perception On 26/07/11 3:41 p.m., Sampo Syreeni wrote: On 2011-07-26, Fons Adriaensen wrote: I certainly don't want you to waste your money on fancy speaker cables. Never thought otherwise. That's obviously never been what we do here. ;) But resistance does matter, so a good cross section such as 2.5 mm^2 puts you on the safe side. What I was trying to ask is, what's the real problem with resistance, especially with regard to a passive speaker and a modern, A/B class solid state end stage? I mean, I don't really see cable resistance shifting their operating point much, even with feedback, within the audible range. What is it that I'm missing? I swapped out some lamp cable on the speakers of a stereo setup some years back with some cheap stranded speaker cable I bought at Costco. Each core of the cable was about 3 times the cross sectional area of the lamp cord (each core of the speaker cable was about 3/16 in dia). The distances were not great, 5 or 6 feet. The improvement in stereo imaging was huge. Previously the image had wandered around between the speakers seemingly at random, now it was rock solid at the point wherever it was when I recorded it. ___ 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/20110727/2a25f5c3/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
my favourite visual image is of a boeing 747. it always seems to fly so slow. we seem to have, in our brains, a 'size' for aircraft, so we can use that to compute speed from angular momentum. so small aircraft wiz by and big ones lumber. what models do we create for sound objects? umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar From: davehuntau...@btinternet.com Date: Wed, 27 Jul 2011 11:01:32 +0100 To: sursound@music.vt.edu Subject: Re: [Sursound] Distance perception On 26 Jul 2011, at 17:00, sursound-requ...@music.vt.edu wrote: Date: Mon, 25 Jul 2011 20:18:42 -0400 From: Marc Lavall?e m...@hacklava.net After reading this difficult thread (I'm replying with a new title), I have simple questions about room sizes and speaker distances. Imagine two rooms with proper acoustic characteristics and treatments for ambisonics reproduction: the first is 3mX4m and the other is four times larger in surface (9mX12m). In both rooms there's a horizontal hexagon of speakers, and 5 speakers are against a wall. When NFC is applied in both rooms, do they sound the same in terms of distance perception when playing the same recording? Or is the same sound object appear to be twice as far in the largest room? As J?rn has pointed out, the effect of the different acoustics of the rooms is hard to eliminate, and speaker placement relative to walls and other surfaces also has audible consequences. Anechoic rooms are hard to achieve, and are rather unpleasant and disturbing to be in. It is would be difficult to do an A/B comparison. So, it is a rather hypothetical, if relevant, question. A better test would be two identical or similar outdoor rigs at different distances matched in level, with the ability to switch between them. The 40' geese phenomenon has been mentioned many times. John Leonard's recording, obviously fairly close perspective, when played on large systems gives the impression of very large geese. No-one seems to have an explanation for this. Possibly it is due to conflicting perceptual cues, visual as well as aural. Even without any visual aspect close sound sources seem 'bigger'. Aural perspective is not the same as visual perspective, though there are some similarities. Visual distance acuity is probably not much better than aural distance acuity. Both rely on comparison, experience and supposition. My hunch, which I cannot back up with formal theory, is that distance perception is relative rather than absolute. So, I would expect the two 'rooms' to sound broadly similar though not identical, assuming 'proper acoustic characteristics' and appropriate NFC. Distance perception would be consistent, though different, in each 'room'. Apart from widening the listening sweet spot, are larger rooms better at reproducing distance cues when using the same speaker configuration? It has been said several times on this list that the size of the sweet spot is related to wavelength and not the size of the speaker rig, and I'm not knowledgeable enough to disagree. Certainly larger rooms have later and lower level reflections, with lower frequency resonant nodes and a more even frequency distribution of the harmonics of those nodes. Speakers can be more easily located away from walls and corners, resulting in direct sound sound from them arriving earlier and being louder than reflected sound. Is distance perception directly related to speaker distances? I suspect that that it is related in the case of ambisonics, though not directly. This is more psychoacoustics than just physics or acoustics. Ciao, Dave Hunt ___ 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/20110727/335f0164/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
I wrote the following as a guide for internal use at my work-place a few years back: One don't that I hold close is this: Don't be mislead by the many snake oil and, smoke and mirrors cable vendors that seem to imbue speaker cables with magical (and astronomically expensive) properties. No matter what Monster Cable, Audioquest, or Cardas claim (or any other esoteric speaker wire manufacturer for that matter), there has never been any proof in any unbiased listen test that there is any benefit from using these snake oil, and smoke and mirrors inventions. [I still stand absolutely by this statement... if you are one of the sad souls that believe they can hear a difference, then you deserve to waste ALL your money on magical items - I have some acoustic candles for sale they cost $1000 each and you must use one per speaker in your listening room the benefits are when lit, you can find each speaker when you turn the lights off). The most amusing claim is that some speaker wires are directional... yes, some manufacturers have decided that their cables must be installed in a particular orientation (usually indicated by an arrow printed on the outer jacket of the cable indicating the direction from the amp to the speaker that the wire is designed to be used. All sorts of claims are made trying to justify this. However speakers are inherently AC (Alternating Current) devices, and hence the electrons in a speaker wire spend just as much time traveling in one direction, as they do the other, so there is no fathomable reasoning that explains just how a speaker cable can possibly be directional, well excepting possibly being able to charge 10 times more to cover the cost of printing the arrows... In fact if you consider this claim further, the more you realize the wacko aspect to this - if the cable truly did work better in one direction versus the other, then the resultant sound cannot possibly be anyt hing other than distorted when the electrons are flowing in the reverse direction! Another odd claim heard for some of the astoundingly expensive speaker connects on the market* is that 'normal' speaker cables exhibit some resonance in the audio band, due to their claimed transmission line properties (since it is common to model a cable as an RLC network). While the RLC model is not invalid, the (usually unsubstantiated) claim that the resonance occurs in the audio band (most often mentioned is 1.5kHz), is very easily proven through basic electronic math to be hopelessly incorrect, and even for a long 50 foot 10AWG cable of quite humble specification, the resonant frequency calculates out to be 2.02MHz (some 2 magnitudes beyond human hearing)! In reality cables DO NOT resonate at all! The model represented here is single RLC lumped circuit for simplicity and is only accurate at audio frequencies for circuit analysis. A speaker cable is actually a distributed element and should be represented as infinite number of lumped RLC models. As an infinite number o f lumped RLC circuits are modeled becoming its true distributed form factor, we see the resonance frequency go to infinity. In order to shorten this discussion the most basic don't is, don't buy any cable that claims anything other than the simple design goal of connecting an amplifier to a speaker. So what does matter? The bottom line is that the speaker cable DC resistance should by rule -of-thumb present no more than 5% of the impedance load presented by the speaker, and hence the ONLY real issue of concern is the resistance of the selected wire per foot. The speakers I use most often have a rated impedance of 4 Ohms, hence we do not want to see a DC resistance greater than 0.2 Ohms for the cable run. In general the distance run per wire gauge recommendations I use are as follows: Up to 40 feet : 14AWG 40-60 feet: 12 AWG 60-100 feet: 10 AWG - Neil On Jul 27, 2011, at 8:03 AM, umashankar mantravadi wrote: years ago (no decades ago) i found what a huge difference it made if the wires were reasonably thick, and cut to be exactly same length. cutting them to same length is problematic with eight loudspeakers (unless the amp sits in the sweet spot) but my next rig, in my own house, in bangalore next year, will have same length wires to all the speakers. umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar Date: Tue, 26 Jul 2011 21:57:49 -0700 From: d...@dgvo.net To: sursound@music.vt.edu Subject: Re: [Sursound] Distance perception On 26/07/11 3:41 p.m., Sampo Syreeni wrote: On 2011-07-26, Fons Adriaensen wrote: I certainly don't want you to waste your money on fancy speaker cables. Never thought otherwise. That's obviously never been what we do here. ;) But resistance does matter, so a good cross section such as 2.5 mm^2 puts you on the safe side. What I was trying to ask is, what's the real problem with resistance, especially
Re: [Sursound] Distance perception (really speaker wire discussion!)
Oh dear. LOL April edition was it? LOL havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar From: neil.water...@asti-usa.com Date: Wed, 27 Jul 2011 08:20:02 -0400 To: sursound@music.vt.edu Subject: Re: [Sursound] Distance perception (really speaker wire discussion!) I wrote the following as a guide for internal use at my work-place a few years back: One don't that I hold close is this: Don't be mislead by the many snake oil and, smoke and mirrors cable vendors that seem to imbue speaker cables with magical (and astronomically expensive) properties. No matter what Monster Cable, Audioquest, or Cardas claim (or any other esoteric speaker wire manufacturer for that matter), there has never been any proof in any unbiased listen test that there is any benefit from using these snake oil, and smoke and mirrors inventions. [I still stand absolutely by this statement... if you are one of the sad souls that believe they can hear a difference, then you deserve to waste ALL your money on magical items - I have some acoustic candles for sale they cost $1000 each and you must use one per speaker in your listening room the benefits are when lit, you can find each speaker when you turn the lights off). The most amusing claim is that some speaker wires are directional... yes, some manufacturers have decided that their cables must be installed in a particular orientation (usually indicated by an arrow printed on the outer jacket of the cable indicating the direction from the amp to the speaker that the wire is designed to be used. All sorts of claims are made trying to justify this. However speakers are inherently AC (Alternating Current) devices, and hence the electrons in a speaker wire spend just as much time traveling in one direction, as they do the other, so there is no fathomable reasoning that explains just how a speaker cable can possibly be directional, well excepting possibly being able to charge 10 times more to cover the cost of printing the arrows... In fact if you consider this claim further, the more you realize the wacko aspect to this - if the cable truly did work better in one direction versus the other, then the resultant sound cannot possibly be an yt hing other than distorted when the electrons are flowing in the reverse direction! Another odd claim heard for some of the astoundingly expensive speaker connects on the market* is that 'normal' speaker cables exhibit some resonance in the audio band, due to their claimed transmission line properties (since it is common to model a cable as an RLC network). While the RLC model is not invalid, the (usually unsubstantiated) claim that the resonance occurs in the audio band (most often mentioned is 1.5kHz), is very easily proven through basic electronic math to be hopelessly incorrect, and even for a long 50 foot 10AWG cable of quite humble specification, the resonant frequency calculates out to be 2.02MHz (some 2 magnitudes beyond human hearing)! In reality cables DO NOT resonate at all! The model represented here is single RLC lumped circuit for simplicity and is only accurate at audio frequencies for circuit analysis. A speaker cable is actually a distributed element and should be represented as infinite number of lumped RLC models. As an infinite numb er o f lumped RLC circuits are modeled becoming its true distributed form factor, we see the resonance frequency go to infinity. In order to shorten this discussion the most basic don't is, don't buy any cable that claims anything other than the simple design goal of connecting an amplifier to a speaker. So what does matter? The bottom line is that the speaker cable DC resistance should by rule -of-thumb present no more than 5% of the impedance load presented by the speaker, and hence the ONLY real issue of concern is the resistance of the selected wire per foot. The speakers I use most often have a rated impedance of 4 Ohms, hence we do not want to see a DC resistance greater than 0.2 Ohms for the cable run. In general the distance run per wire gauge recommendations I use are as follows: Up to 40 feet : 14AWG 40-60 feet: 12 AWG 60-100 feet: 10 AWG - Neil On Jul 27, 2011, at 8:03 AM, umashankar mantravadi wrote: years ago (no decades ago) i found what a huge difference it made if the wires were reasonably thick, and cut to be exactly same length. cutting them to same length is problematic with eight loudspeakers
Re: [Sursound] Distance perception (really speaker wire discussion!)
but of course ! umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar From: zoanne...@yahoo.co.uk To: sursound@music.vt.edu Date: Wed, 27 Jul 2011 13:26:47 +0100 Subject: Re: [Sursound] Distance perception (really speaker wire discussion!) Oh dear. LOL April edition was it? LOL havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) umashankar i have published my poems. read (or buy) at http://stores.lulu.com/umashankar From: neil.water...@asti-usa.com Date: Wed, 27 Jul 2011 08:20:02 -0400 To: sursound@music.vt.edu Subject: Re: [Sursound] Distance perception (really speaker wire discussion!) I wrote the following as a guide for internal use at my work-place a few years back: One don't that I hold close is this: Don't be mislead by the many snake oil and, smoke and mirrors cable vendors that seem to imbue speaker cables with magical (and astronomically expensive) properties. No matter what Monster Cable, Audioquest, or Cardas claim (or any other esoteric speaker wire manufacturer for that matter), there has never been any proof in any unbiased listen test that there is any benefit from using these snake oil, and smoke and mirrors inventions. [I still stand absolutely by this statement... if you are one of the sad souls that believe they can hear a difference, then you deserve to waste ALL your money on magical items - I have some acoustic candles for sale they cost $1000 each and you must use one per speaker in your listening room the benefits are when lit, you can find each speaker when you turn the lights off). The most amusing claim is that some speaker wires are directional... yes, some manufacturers have decided that their cables must be installed in a particular orientation (usually indicated by an arrow printed on the outer jacket of the cable indicating the direction from the amp to the speaker that the wire is designed to be used. All sorts of claims are made trying to justify this. However speakers are inherently AC (Alternating Current) devices, and hence the electrons in a speaker wire spend just as much time traveling in one direction, as they do the other, so there is no fathomable reasoning that explains just how a speaker cable can possibly be directional, well excepting possibly being able to charge 10 times more to cover the cost of printing the arrows... In fact if you consider this claim further, the more you realize the wacko aspect to this - if the cable truly did work better in one direction versus the other, then the resultant sound cannot possibly b e an yt hing other than distorted when the electrons are flowing in the reverse direction! Another odd claim heard for some of the astoundingly expensive speaker connects on the market* is that 'normal' speaker cables exhibit some resonance in the audio band, due to their claimed transmission line properties (since it is common to model a cable as an RLC network). While the RLC model is not invalid, the (usually unsubstantiated) claim that the resonance occurs in the audio band (most often mentioned is 1.5kHz), is very easily proven through basic electronic math to be hopelessly incorrect, and even for a long 50 foot 10AWG cable of quite humble specification, the resonant frequency calculates out to be 2.02MHz (some 2 magnitudes beyond human hearing)! In reality cables DO NOT resonate at all! The model represented here is single RLC lumped circuit for simplicity and is only accurate at audio frequencies for circuit analysis. A speaker cable is actually a distributed element and should be represented as infinite number of lumped RLC models. As an infinite nu mb er o f lumped RLC circuits are modeled becoming its true distributed form factor, we see the resonance frequency go to infinity. In order to shorten this discussion the most basic don't is, don't buy any cable that claims anything other than the simple design goal of connecting an amplifier to a speaker. So what does matter? The bottom line is that the speaker cable DC resistance should by rule -of-thumb present no more than 5% of the impedance load presented by the speaker, and hence the ONLY real issue of concern is the resistance of the selected wire per foot. The speakers I use most often have a rated impedance of 4 Ohms, hence we do not want to see a DC resistance greater than 0.2 Ohms for the cable run. In general the distance run per wire gauge recommendations I use are as follows
Re: [Sursound] Distance perception (really speaker wire discussion!)
Surely a Duracell would be perfect for the job, I mean, it does wonders for that rabbit... The problem with using a cheap battery for doing this is that those electrons which are really not able to move anymore (for example those having a broken leg, the result of smashing into another one going in the opposite direction) are not flushed out, but merely reduced to debris that will impede the flow of the new electrons. To really clean up your cable you need something more sophisticated and expensive, the more expensive the better. -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1390 / Virus Database: 1518/3790 - Release Date: 07/26/11 -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110727/8c30093f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
Am I missing something? You send electrons and the speaker cone moves out, o.k. It comes back by itself. But surely you want it to move _in_ as well? How do you do that without positrons. (I think that's right, most things in surround sound seem counter-intuitive: So I doubt if it is positrons out / electrons in?) Anyway, I've learnt something: I always thought the little arrows on all my speaker cables meant they were made by workers in prisons (or is the arrow as a prison sign non-ISO / ITU?). Michael On Wed, Jul 27, 2011 at 05:52:58PM +0530, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) umashankar The problem with using a cheap battery for doing this is that those electrons which are really not able to move anymore (for example those having a broken leg, the result of smashing into another one going in the opposite direction) are not flushed out, but merely reduced to debris that will impede the flow of the new electrons. To really clean up your cable you need something more sophisticated and expensive, the more expensive the better. -- FA ___ 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] Distance perception (really speaker wire discussion!)
I found this message really intriguing since the rabbit is really in an ad for Energizer batteries not Duracell. One wonders why advertising is useful! I have had exactly the same experience. The ads are memorable, but what they are ads FOR is not. Better than the original--who can forget the old master at the easel. But what was being advertised? It's not nice to fool Mother Nature'. What was that an ad for? I can't believe I ate the whole thing You ate it, Ralph --unforgettable but what was the product? I suppose this is good--the culture is added to without benefit to the probably undeserving! Robert On Wed, 27 Jul 2011, Richard wrote: Surely a Duracell would be perfect for the job, I mean, it does wonders for that rabbit... The problem with using a cheap battery for doing this is that those electrons which are really not able to move anymore (for example those having a broken leg, the result of smashing into another one going in the opposite direction) are not flushed out, but merely reduced to debris that will impede the flow of the new electrons. To really clean up your cable you need something more sophisticated and expensive, the more expensive the better. -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1390 / Virus Database: 1518/3790 - Release Date: 07/26/11 -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110727/8c30093f/attachment.html ___ 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] Distance perception
Speaker wiring really is a hot topic on all audio related forums. Next time I'll use the term speaker wire instead of lamp cord. :-) For a small and inefficient Kef satellite speaker (3 with a tiny coaxial tweeter and internal crossover circuit), unable to reproduce frequencies lower that 120Hz, driven by a dirt cheap 10W class-T amp, for listening at a maximum distance of 2.5 meters, I doubt that using short lamp cords will be my worst problem; sleeping well, for example, is a better investment to improve my listening experience than getting better cables or amplified speakers. For lower frequencies I use small subs with integrated amps; I have no idea if Kef used some negative impedance trick in their cheapest sub. Wed, 27 Jul 2011 07:43:37 +, Fons Adriaensen f...@linuxaudio.org a écrit : On Wed, Jul 27, 2011 at 01:41:51AM +0300, Sampo Syreeni wrote: On 2011-07-26, Fons Adriaensen wrote: I certainly don't want you to waste your money on fancy speaker cables. Never thought otherwise. That's obviously never been what we do here. ;) But resistance does matter, so a good cross section such as 2.5 mm^2 puts you on the safe side. What I was trying to ask is, what's the real problem with resistance, especially with regard to a passive speaker and a modern, A/B class solid state end stage? I mean, I don't really see cable resistance shifting their operating point much, even with feedback, within the audible range. What is it that I'm missing? When the voice coil of speaker moves in the magnetic field it is surrounded by it generates a voltage proportional to its velocity. Ideally that voltage should be equal to the one produced by the amplifier: in that case the amplifier has complete control over the movement. You can easily test this: disconnect the speaker and gently push the cone of the woofer. You will see it moves quite easily. Now connect the speaker and switch on the amplifier, OR just short-circuit the speaker terminals. In both cases the speaker sees a very low impedance, and it will resist movement. In practice there is a problem: any resistance in series with the 'ideal' voice coil means that those two voltages are not equal and the amplifier is not fully in control. The resistance that appears in series is the the sum of the DC resistance of the voice coil itself, cable resistance and the output impedance of the amplifier. This sum should be as small as possible, and cable resistance can be a significant part of it. One advantage of integrated amps/speakers is that the amplifier can be designed to compensate for this resistance by giving it a negative impedance. This has to be controlled very carefully - overdoing it makes the whole thing unstable and ready to auto-destruct. Which is why it can't be done with separate amps and speakers. Ciao, ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
Wed, 27 Jul 2011 07:53:18 +, Fons Adriaensen f...@linuxaudio.org wrote : On Tue, Jul 26, 2011 at 10:26:49PM -0400, Marc Lavallée wrote: How large is the resulting stereo image? As large as you make it, see below. In your earlier post you mentioned that you can't explain why you like virtual speakers better than using real speakers. Can you describe some perceived differences? For example, how are rendered mono signals; are they right in the middle or smeared between the two virtual speakers? In other words, is localization better when using virtual speakers? Is your technique documented somewhere? Can it work with a horizontal hexagon? With 2rd order AMB? Sure. There isn't much to document, just set up your AMB system and use two AMB panners for the L and R signals. Easy! -- Marc ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On 07/27/2011 04:26 AM, Marc Lavallée wrote: Tue, 26 Jul 2011 21:32:26 +, Fons Adriaensenf...@linuxaudio.org wrote : The thing is that I very much prefer listening to stereo using two virtual speakers panned into 3rd order AMB rather than sending L,R directly to two of the speakers. It's very interesting! How large is the resulting stereo image? Is your technique documented somewhere? as fons said, it's just panning. at lac 2010, i presented a paper on using this technique to play back arbitrary discrete multichannel works on an ambisonic rig, with some listening tests: http://stackingdwarves.net/public_stuff/linux_audio/lac2010/day2_1130_General_purpose_Ambisonic_playback_systems_for_electroacoustic_concerts.ogv executive summary: in the general case, it's very nice. for some signals and some expectations, it does not work that well. but fons' preference for the bastardized stereo sound over native reproduction is not shared by most people i talked to, unless you make the triangle significantly wider than 60°, at which point the wow! effect takes over :) Can it work with a horizontal hexagon? With 2rd order AMB? easily. my own tests were all on 3rd order rigs, but i've done it on a hexagon at home, and it was ok. -- 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] Distance perception
On Wed, Jul 27, 2011 at 01:19:50PM -0400, Marc Lavallée wrote: In your earlier post you mentioned that you can't explain why you like virtual speakers better than using real speakers. Can you describe some perceived differences? For example, how are rendered mono signals; are they right in the middle or smeared between the two virtual speakers? In other words, is localization better when using virtual speakers? This is very subjective, but yes, I have the impression it is better. Also the speakers tend to disappear as being the sources of the sound and there is less interaction from the room - the sensation that the sound is 'just there' is stronger than for straight stereo. But again, this is quite subjective and may be particular for my setup. If you have the required hardware I'd say: just try it ! Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On 27 Jul 2011, at 18:33, Fons Adriaensen f...@linuxaudio.org wrote: On Wed, Jul 27, 2011 at 01:19:50PM -0400, Marc Lavallée wrote: In your earlier post you mentioned that you can't explain why you like virtual speakers better than using real speakers. Can you describe some perceived differences? For example, how are rendered mono signals; are they right in the middle or smeared between the two virtual speakers? In other words, is localization better when using virtual speakers? This is very subjective, but yes, I have the impression it is better. Also the speakers tend to disappear as being the sources of the sound and there is less interaction from the room - the sensation that the sound is 'just there' is stronger than for straight stereo. But again, this is quite subjective and may be particular for my setup. If you have the required hardware I'd say: just try it ! Do you find it varies with material? People don't always say it this way, but sometimes increased localisation blur is nice! S. Ciao, -- FA ___ 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] Distance perception (really speaker wire discussion!)
If you have a suitable LiOn battery pack, shorting the terminals out with the cable perks up most the tired electrons - and the subsequent explosion will remove any that are too far gone... On Jul 27 2011, Sampo Syreeni wrote: On 2011-07-27, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On Wed, Jul 27, 2011 at 06:50:03PM +0100, Scott Wilson wrote: Do you find it varies with material? People don't always say it this way, but sometimes increased localisation blur is nice! Good question, but I can't give a definite answer. Most of the material I've been working on there is contemporary (2nd half of 20th century) music for small ensembles, and recorded by myself in a place I know very well. One exception is a concert with madrigals by Adriano Banchieri (late 16th cent.). For that one I could use for the first time (in that place) a suspended ORTF pair, but it was just a bit too far from the stage (practical constraints) and I'm not 100% happy with the result. I'll try to listen to some more diverse material and report my impressions. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception (really speaker wire discussion!)
I have been browsing this list long enough to observe that this phenomena only occurs (or at least is only reported, on this list, albeit with annual regularity) in Northern Hemisphere summers. Down under, the summers are so hot that the electrons want to pass through cable as quickly as possible, so they exhibit an exact opposite characteristic: Temporal Intensification Dilation (also DIT, unfortunately); thought to be the caused as them exceeding the speed of light in order to 'get the f*** outa there'. The phenomena can be reversed, or at least alleviated from a 3rd person perspective, by plugging the cables into a live mains socket and biting hard on the other end. David On 28/07/2011, at 3:42 AM, Sampo Syreeni wrote: On 2011-07-27, umashankar mantravadi wrote: havent you heard of tired electron distortion ? (TID). the electrons in speaker wire get tired moving back and forth and not going anywhere. the solution is to disconnect the speaker every few hours connect a battery one side and short the other, so all the old electrons can be flushed out (i think i read this in the wireless world) Alternatively you can have spare cables, and slowly drain them over night in an upright position. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ Dr David Worrall Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Projects, Music Council of Australia worrall.avatar.com.au sonification.com.au -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110728/bffc3272/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On 07/26/2011 02:18 AM, Marc Lavallée wrote: Imagine two rooms with proper acoustic characteristics and treatments for ambisonics reproduction: the first is 3mX4m and the other is four times larger in surface (9mX12m). In both rooms there's a horizontal hexagon of speakers, and 5 speakers are against a wall. regardless of room size, they will require a bit of equalisation. if the speakers are designed to be close to a boundary surface, the one that's not against a wall needs (gentle) bass boost. vice versa, if your speakers are designed to be free-standing, the five speakers need some attenuation at LF. if you're still shopping for speakers, i found that the genelec 8030 have a nice built-in bass eq which can be used to deal with this issue. i was able to even out the bass response of a rig where most speakers are next to two boundary surfaces and a few only next to one. of course, you could also do this in software. When NFC is applied in both rooms, do they sound the same in terms of distance perception when playing the same recording? NFC is not a constant. the amount of NFC depends on the distance to the speaker. Or is the same sound object appear to be twice as far in the largest room? actually, if you hope to get distance perception so good that the notion of twice as far begins to make sense, then you're in for some heartache. that's why i said distance cues are gimmickry earlier. the actual curvature of the soundfield (which is all that NFC does for you) is not a very robust distance cue. the delay of the (reproduced) floor reflection is a lot more helpful, as is the ratio of direct to reverberated sound (but the latter doesn't help soundman john with his spitfires). so why get gung-ho about a cue of secondary importance, for a perception apparatus that doesn't care much anyways... the problem is that your listening room floor reflection will always be different from and stronger than the recorded floor reflection, which pulls the image towards the speaker circle. if you close your eyes and find yourself able to suspend your disbelief long enough to actually imagine yourself in a cathedral listening to an organ, then rejoice and be happy. don't spoil the magic by gauging the distance. it's not going to happen. the sad and simple fact is that _no_ surround rig can get the distance unambiguously right in any but anechoic conditions. and before you run off to shop for styrofoam, be warned that most recordings would sound utter crap in anechoic conditions, because nobody mixes for that. moreover, the phasing problems of our beloved ambisonic technique would become very obnoxious indeed. the deader you make your room, the more hope you have to get precise distance information. at the same time, the rig will sound less pleasant and artefacts will become more obvious. since humans suck at absolute distance perception anyways, your best bet is to be content with some degree of distance discriminination. that is, you want to hear the woodwinds _somewhere_behind_ the strings. you wouldn't normally care how many metres. this usually works well if the recording is ok. Apart from widening the listening sweet spot, are larger rooms better at reproducing distance cues when using the same speaker configuration? Is distance perception directly related to speaker distances? as mentioned before, the floor reflection is a very strong distance cue at close range under semi-anechoic conditions (i.e. if you want to gauge the distance of that sabre-toothed tiger or the potential mating candidate). if you're right next to the sound source, the floor reflection will have the longest delay. far away, the delay will be negligible. the general case is dly = 340 / (sqrt(ear_height^2 + half_distance^2) * 2) when a listening room first reflection is strong and early, it will dominate your sense of distance. in that sense, larger rigs have the potential to be less intrusive wrt distance perception. -- 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] Distance perception
sorry, itchy trigger finger... On 07/26/2011 10:14 AM, Jörn Nettingsmeier wrote: as mentioned before, the floor reflection is a very strong distance cue at close range under semi-anechoic conditions (i.e. if you want to gauge the distance of that sabre-toothed tiger or the potential mating candidate). uhm, i realise that the latter example is a bit dated - who meets significant others in the great outdoors, these days. for clubbing, the dominant cue should be direct-to-reverb ratio, unless you have to fall back to olfactory and visual cues entirely because of the extremely loud music. if you're right next to the sound source, the floor reflection will have the longest delay. far away, the delay will be negligible. the general case is dly = 340 / (sqrt(ear_height^2 + half_distance^2) * 2) minus the straight-path delay of course: dly = 340 / (sqrt(ear_height^2 + (distance/2)^2) * 2 - distance) -- 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] Distance perception
Tue, 26 Jul 2011 10:14:50 +0200, Jörn Nettingsmeier netti...@stackingdwarves.net wrote : regardless of room size, they will require a bit of equalisation. if the speakers are designed to be close to a boundary surface, the one that's not against a wall needs (gentle) bass boost. vice versa, if your speakers are designed to be free-standing, the five speakers need some attenuation at LF. The smallest KEF eggs should be fine against the walls, as you already wrote me. Two will be free-standing (front and back) and will need a bit more electronic correction. if you're still shopping for speakers, i found that the genelec 8030 have a nice built-in bass eq which can be used to deal with this issue. i was able to even out the bass response of a rig where most speakers are next to two boundary surfaces and a few only next to one. of course, you could also do this in software. I will do it in software. It's a domestic setup, so I don't need expensive active speakers and cabling; I prefer to use very small speakers with lamp cords. the problem is that your listening room floor reflection will always be different from and stronger than the recorded floor reflection, which pulls the image towards the speaker circle. Then less reflections means less localization of the speakers? the sad and simple fact is that _no_ surround rig can get the distance unambiguously right in any but anechoic conditions. and before you run off to shop for styrofoam, be warned that most recordings would sound utter crap in anechoic conditions, because nobody mixes for that. What follows is just my opinion. We are free to record and mix in any imaginable ways, so recordings sound imperfect in most situations. There's little a listening room can do to beautify recordings and reproduction systems, unless the room is considered as a musical instrument. Even in a small room with too much acoustic treatment, I may be pleasantly surprised by some very good recordings, and find some qualities in some very bad recordings; anything can happen in the middle, and low expectations is the key to happiness. What I expect from listening to ambisonic recordings is a better envelopment and a sense of realism not found in stereo recordings. I also expect some new experiences from field recordings and electroacoustic music for ambisonics. I also want to compare ambisonics to other reproduction methods; maybe stereo and 5.1 are not so bad... The other use for all those speakers is to add a bit of hall reverberation to some dry stereo recordings. moreover, the phasing problems of our beloved ambisonic technique would become very obnoxious indeed. Obnoxious phasing problems? Now I'm afraid! ;-) Maybe I spent decades listening to obnoxious problems I never noticed... I'll do my best to control phasing problems at the sweet spot. the deader you make your room, the more hope you have to get precise distance information. at the same time, the rig will sound less pleasant and artefacts will become more obvious. since humans suck at absolute distance perception anyways, your best bet is to be content with some degree of distance discriminination. that is, you want to hear the woodwinds _somewhere_behind_ the strings. you wouldn't normally care how many metres. this usually works well if the recording is ok. I found good acoustic panels, and I have to decide how much surface to cover. I once built large and thick panels to cover half of the walls and 2/3 of the ceiling. There was also a wool carpet with foam under it. The room was so dead that I was able to listen to my heart beat. I remember how sharp the stereo image was and how the speakers were not easy to localize with good recordings. Of course the room was a bit oppressive, almost like a recording booth... I hope to find a better compromise between analytic listening and listening for enjoyment. when a listening room first reflection is strong and early, it will dominate your sense of distance. in that sense, larger rigs have the potential to be less intrusive wrt distance perception. Right: first reflections should be better controlled in a small room. if you're right next to the sound source, the floor reflection will have the longest delay. far away, the delay will be negligible. the general case is dly = 340 / (sqrt(ear_height^2 + half_distance^2) * 2) minus the straight-path delay of course: dly = 340 / (sqrt(ear_height^2 + (distance/2)^2) * 2 - distance) So floor and ceiling reflections also need to be controlled, even more in a small room. The difficulty is how to leave some harmless and lively reflections. Maybe that adding a few small diffusors would be a good compromise. Thanks! -- Marc ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
Some papers that may be of interest: Takahashi, A Novel View of Hearing in Reverberation, Neuron, Volume 62, Issue 1, 6-7, 16 April 2009 doi:10.1016/j.neuron.2009.04.004 Devore, et al., Accurate Sound Localization in Reverberant Environments Is Mediated by Robust Encoding of Spatial Cues in the Auditory Midbrain, Neuron, Volume 62, Issue 1, 123-134, 16 April 2009 doi:10.1016/j.neuron.2009.02.018 Antje Ihlefeld and Barbara G. Shinn-Cunningham, Effect of source spectrum on sound localization in an everyday reverberant room, J. Acoust. Soc. Am. Volume 130, Issue 1, pp. 324-333 (2011) http://dx.doi.org/10.1121/1.3596476 -- Aaron Heller (hel...@ai.sri.com) Menlo Park, CA US ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On Tue, Jul 26, 2011 at 04:35:39PM -0400, Marc Lavallée wrote: I will do it in software. It's a domestic setup, so I don't need expensive active speakers and cabling; I prefer to use very small speakers with lamp cords. Lamp cords ? Use at least 2.5 mm^2 ! the problem is that your listening room floor reflection will always be different from and stronger than the recorded floor reflection, which pulls the image towards the speaker circle. Then less reflections means less localization of the speakers? Yes, in general this is true, and it's quite logical - we use reflections to build up an 'acoustic picture' of a space, and in turn that is used to aid localisation. If the cues provided by room reflections dominate those reproduced from the recording you can't but identify the speakers as the source. the sad and simple fact is that _no_ surround rig can get the distance unambiguously right in any but anechoic conditions. and before you run off to shop for styrofoam, be warned that most recordings would sound utter crap in anechoic conditions, because nobody mixes for that. That is really a very valid observation. Almost all recordings rely on the listener's room acoustics to do part of the work. And studio control rooms usually have well controlled acoustics, but they are by no means anechoic. Which means that something similar is expected of the listening environment. What I expect from listening to ambisonic recordings is a better envelopment and a sense of realism not found in stereo recordings. I also expect some new experiences from field recordings and electroacoustic music for ambisonics. I also want to compare ambisonics to other reproduction methods; maybe stereo and 5.1 are not so bad... They are not. Very nice results can be achieved with either. The other use for all those speakers is to add a bit of hall reverberation to some dry stereo recordings. Depends a bit on the type of music you are listening to, but in general that is a good idea for any type of music that is normally played in concert hall like environments. There is another thing which I can't explain ATM. I've been working lately most of the time in a studio that has a regular octagon of speakers for Ambisonic monitoring. But half of the work done there is just stereo. The thing is that I very much prefer listening to stereo using two virtual speakers panned into 3rd order AMB rather than sending L,R directly to two of the speakers. But I can't ATM explain why. So floor and ceiling reflections also need to be controlled, even more in a small room. Yes. I recently moved home, and my new working environment is a rather small and boxy room. Its only redeeming feature is that the ceiling is not horizontal but inclined by 15 degress or so. The floor is hardwood, nice for recording but in this case it doesn't help for listening. When I first listened to some reference recordings in this place I was 'not amused' at all. But putting a thick carpet in front of the speakers changed the picture quite dramatically. The room is still a disaster for good LF response, but otherwise it has become acceptable by reducing a very strong floor reflection. The difficulty is how to leave some harmless and lively reflections. Maybe that adding a few small diffusors would be a good compromise. Diffusers are almost never a bad idea. Ciao, -- FA ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On 2011-07-26, Fons Adriaensen wrote: Lamp cords ? Use at least 2.5 mm^2 ! Where does this come from? I've never though cable geometry matters much at all, unless your pumping so much power through a cable over such a long distance that you have to worry about ohmic heating and the like. And even there, I've always thought changing resistance would mostly affect a tube end stage, which we've almost done away with already in favour of the A/B class solid state one. And at audio frequencies, shouldn't even feedback oscillation and its kin be well below perceptual thresholds? True, my cables are multistrand ones with approximately that cross-sectional area per polarity. But not because of some esoteric, audiophile reason. It's because that's what they sell the cheapest as speaker cable in my local shop. -- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On 07/27/2011 12:41 AM, Sampo Syreeni wrote: On 2011-07-26, Fons Adriaensen wrote: I certainly don't want you to waste your money on fancy speaker cables. Never thought otherwise. That's obviously never been what we do here. ;) But resistance does matter, so a good cross section such as 2.5 mm^2 puts you on the safe side. What I was trying to ask is, what's the real problem with resistance, especially with regard to a passive speaker and a modern, A/B class solid state end stage? I mean, I don't really see cable resistance shifting their operating point much, even with feedback, within the audible range. What is it that I'm missing? power transmission impedance matching. if you look at the spec sheet of a commercial p.a. amplifier, 9 times out of 10 you will see twice the power rating for 4 ohm loads than for 8 ohms. usually this means you connect two 8 ohm enclosures in parallel for an optimum load. but obviously any resistance of the wire will limit the power you can draw from the amp. say you're using the really cheap NYM 3G1.5 wire, which has about 14 ohms per km. for a practical speaker line length of 20m, that's 0.3 ohms. i won't make a fool of myself here by giving precise numbers after a day of mixing and three bottles of beer, but it's easy to see that 0.3 compared to 4 ohms is a significant fraction. -- 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] Distance perception
Tue, 26 Jul 2011 21:32:26 +, Fons Adriaensen f...@linuxaudio.org wrote : Lamp cords ? Use at least 2.5 mm^2 ! I'll use less than 10 meters of cabling to drive 10W max in each tiny 6 ohms speaker. So I'm not worried at all. Gauge 14 or 16 should be fine: http://www.roger-russell.com/wire/wire.htm The thing is that I very much prefer listening to stereo using two virtual speakers panned into 3rd order AMB rather than sending L,R directly to two of the speakers. It's very interesting! How large is the resulting stereo image? Is your technique documented somewhere? Can it work with a horizontal hexagon? With 2rd order AMB? -- Marc ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Distance perception
On 26/07/11 3:41 p.m., Sampo Syreeni wrote: On 2011-07-26, Fons Adriaensen wrote: I certainly don't want you to waste your money on fancy speaker cables. Never thought otherwise. That's obviously never been what we do here. ;) But resistance does matter, so a good cross section such as 2.5 mm^2 puts you on the safe side. What I was trying to ask is, what's the real problem with resistance, especially with regard to a passive speaker and a modern, A/B class solid state end stage? I mean, I don't really see cable resistance shifting their operating point much, even with feedback, within the audible range. What is it that I'm missing? I swapped out some lamp cable on the speakers of a stereo setup some years back with some cheap stranded speaker cable I bought at Costco. Each core of the cable was about 3 times the cross sectional area of the lamp cord (each core of the speaker cable was about 3/16 in dia). The distances were not great, 5 or 6 feet. The improvement in stereo imaging was huge. Previously the image had wandered around between the speakers seemingly at random, now it was rock solid at the point wherever it was when I recorded it. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
Hello Junfeng, it's no easy task to evaluate distance perception under anechoic conditions (which obviously hardly exists). We did this during my PhD research on WFS. Have a look at our paper: Wittek, H., Kerber, S., Rumsey, F. and Theile, G. Spatial perception in Wave Field Synthesis rendered sound fields: Distance of real and virtual nearby sources Preprint #6000, AES 116th Convention, Berlin, 2004 or my thesis on my website: http://www.hauptmikrofon.de/ Good luck, best regards, Helmut Wittek -Ursprüngliche Nachricht- Von: sursound-boun...@music.vt.edu [mailto:sursound-boun...@music.vt.edu] Im Auftrag von Junfeng Li Gesendet: Sonntag, 17. April 2011 03:28 An: Surround Sound discussion group Betreff: [Sursound] distance perception in virtual environments Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high- order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/6 4a7d936/attachment.html ___ 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] distance perception in virtual environments
Helmut Oellers oell...@syntheticwave.de wrote: 2011/4/26 Dave Malham d...@york.ac.uk On 24/04/2011 19:11, Helmut Oellers wrote: ...modern computers are also clever. Today nothing is unaccountable if we know the formula and all variables. That's a BIG assumption - and given the essentially chaotic (in the mathematical sense) nature of the Universe, wrong. We are now pretty certain that nothing is that predictable and that that idea's basically (old) Science Fiction - we have moved from E. E. Doc Smith's Lensman universe ( where ultimately intelligent beings could predict everything because they knew the complete starting conditions and laws of the Universe) to the Discworld universe of Terry Pratchett where one flap of a Quantum Weather Butterfly's *** wings can change the course of the entire Universe (and confound even the Gods). Hello Dave, what you are describing, I would consider as the ?Heisenberg uncertainty principle?, which disclosures, as closer we look at the things, as less we can discover. Accordingly, in the quantum world the random exist, really not computable. However, in the macro world of whole air molecules, the conditions are describable. No, not the Heisenberg uncertainty principle just, as Dave stated, chaos. At times, the weather system gets itself into a chaotic state. The motion of the planets is also thought to be chaotic. These are macro. This example of the weather system gave rise to the (unsubstantiated) claim that the flap of a butterfly’s wings in Brazil can set off a tornado in Texas. (The location of the butterfly and its effects vary.) This very nice example was then purloined and mangled by Terry Prachett who introduced a spurious reference to Quantum Theory. 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] distance perception in virtual environments
Actually, the butterfly flap thing is not really good either. In chaos, things do not cause other things. The system is essentially noncausal. This is a trick point. But if a system depends unstably on its initial state, it makes no real sense to say that it depends on its initial state at all in any detail. The weather has large scale stable aspects--it is almost always warmer in the summer than in the winter for example. But the details of the weather are(it is currently believed) unstable. They are not really caused by anything in any reasonable sense. This is in fact not completely detached from quantum uncertainty because if a system is unstable then it can obviously be knocked about by quantum level changes--since it can be knocked about by arbitrarily small changes of any sort. One merges into the other. Also, there is no reason at all why a quantum uncertainty cannot have macro effects, cf. Schrodinger's cat and many other examples. Time for work. More on this later(if anyone cares) Robert On Thu, 28 Apr 2011, Martin Leese wrote: Helmut Oellers oell...@syntheticwave.de wrote: 2011/4/26 Dave Malham d...@york.ac.uk On 24/04/2011 19:11, Helmut Oellers wrote: ...modern computers are also clever. Today nothing is unaccountable if we know the formula and all variables. That's a BIG assumption - and given the essentially chaotic (in the mathematical sense) nature of the Universe, wrong. We are now pretty certain that nothing is that predictable and that that idea's basically (old) Science Fiction - we have moved from E. E. Doc Smith's Lensman universe ( where ultimately intelligent beings could predict everything because they knew the complete starting conditions and laws of the Universe) to the Discworld universe of Terry Pratchett where one flap of a Quantum Weather Butterfly's *** wings can change the course of the entire Universe (and confound even the Gods). Hello Dave, what you are describing, I would consider as the ?Heisenberg uncertainty principle?, which disclosures, as closer we look at the things, as less we can discover. Accordingly, in the quantum world the random exist, really not computable. However, in the macro world of whole air molecules, the conditions are describable. No, not the Heisenberg uncertainty principle just, as Dave stated, chaos. At times, the weather system gets itself into a chaotic state. The motion of the planets is also thought to be chaotic. These are macro. This example of the weather system gave rise to the (unsubstantiated) claim that the flap of a butterfly?s wings in Brazil can set off a tornado in Texas. (The location of the butterfly and its effects vary.) This very nice example was then purloined and mangled by Terry Prachett who introduced a spurious reference to Quantum Theory. 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 ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
...modern computers are also clever. Today nothing is unaccountable if we know the formula and all variables. Audio is no mysterious. The complete sonic field would be calculatable. The only problem is the huge amount of variables. In principle, yet, we are able to calculate any wave front of the source and any of her reflections in the recording room. The Wave Field Synthesis provides the approach for handling the problem. The procedure can synthesize the complete spatial distribution of all wave fronts. In principle, also all reflections become to restore correct in time, level and direction, at least in the horizontal level of the loudspeaker rows. The really disturbing component always remained, as like at all other audio playback, the additional playback room acoustics, which deliver unwanted reflections. However, at WFS we have a chance for avoiding that problem. All we need is including the playback room properties into the synthesis. By this way becomes possible, subtract the additional detours of single wave fronts in the playback room. Never conventional procedure will be able to that, because direct wave, first reflections and reverberation inseparably merge together in the transmitting channels. Thus, the playback room unavoidably remains the disturbing component in transmitting chain. No chance exists for true spatial audio by that way, thereby. And no chance exists for reproducing the source distance correctly in the traditional way. Regards Helmut www.holophony.net I think rooms are poor substitute, and very recent on evolutionary timescales, for the predictable reflections one gets in a forest. You need the simulated forest (sort of both uniform but also random )for an accurate guess of the start time. Then you delay the direct sound arrival time from there as well as decreasing its amplitude proportional to 1/t (where t is the time-of-flight from start time to arrival at the listener).. if I remember what I tried to do. If you live in a room then expect errors but the same principle applies! We can't and don't determine the direction and distance of a sound with only two ears. We use an infinite 3d array. We just don't know the precise details of the ever-changing array. It is a very clever trick that evolution has come up with! ___ 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/20110424/ca547b2f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
Hi David, you are not alone in your insigthes. Some single discrete reflections are the most important fact for estimation of source distance. There exist research from Helmut Wittek, who was proven, play the reverberation from four different directions is absolutely sufficient. We cannot use the direction of the wave fronts in the reverberation tail for determine the position of the source. Also in the recording room, the reverberation arrives from all possible directions. Another case are the first reflections. Her delay time and direction are the most important fact for approve the source position, what inclusdes its distance and the size impression of the recording room. Such single reflections causing deep comb filter effects and change the perception considerably. On the other hand, for reverberation is valid, what floyd Toole says sometimes: As more reflections esxist as less disturbing there are. ( as far as I remember well his words ). All we need for correct distance reproduction is restore some ingle reflections from her correct starting points and the correct relation between direct wave and reverberation. Regards Helmut www.holophony.net 2011/4/19 dw surso...@dwareing.plus.com Hi List, Just popped in.. It's been a while! IMO it is a combination of time-of-flight and the inverse square law, where t=0 is a virtual point in time determined by the brain as an intercept by plotting a function of the intensity of (primarily) transverse reflections against time. Fortunately it is not necessary to work out how the brain might do this. One needs to concentrate maximising the availability, and accuracy of the information that would be needed to make such a calculation possible, without making too much muddy reverb. in the process. Mono reverb does not seem to play much, or possibly any, part in this. It seems to be extracted in some way from larger ITDs and ILDs ie. transverse discrete reflections. It took me several years to work all this out, and nobody seems to have independently come to the same conclusion in the last decade or so.. so it must be wrong. At least it is free and in the public domain now! My Heli.wav on Audio and Three Dimensional Sound Links* (long gone) was a product of precisely this method of distance synthesis. Regards, David Wareing. ___ 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/20110420/273802eb/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
On 17/04/2011 02:28, Junfeng Li wrote: Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL:https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/64a7d936/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound Hi List, Just popped in.. It's been a while! IMO it is a combination of time-of-flight and the inverse square law, where t=0 is a virtual point in time determined by the brain as an intercept by plotting a function of the intensity of (primarily) transverse reflections against time. Fortunately it is not necessary to work out how the brain might do this. One needs to concentrate maximising the availability, and accuracy of the information that would be needed to make such a calculation possible, without making too much muddy reverb. in the process. Mono reverb does not seem to play much, or possibly any, part in this. It seems to be extracted in some way from larger ITDs and ILDs ie. transverse discrete reflections. It took me several years to work all this out, and nobody seems to have independently come to the same conclusion in the last decade or so.. so it must be wrong. At least it is free and in the public domain now! My Heli.wav on Audio and Three Dimensional Sound Links* (long gone) was a product of precisely this method of distance synthesis. Regards, David Wareing. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
Richard Lee rica...@justnet.com.au wrote: You must simulate at least 2 things. ... You have to simulate early reflections and a reverb pattern appropriate to source distance. MAG has a paper on this under Distance Panners from an idea by Peter Craven. MAG's paper is: M.A. Gerzon, The Design of Distance Panpots, Preprint 3308 of the 92nd Audio Engineering Society Convention, Vienna (1992 Mar.) (Simulating distance effects in directional reproduction.) A commercialisation of this was the TrueVerb product from Waves. 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] distance perception in virtual environments
Hi, Gavin Kearney et al have presented their work on Depth perception in interactive virtual acoustic environments using higher order ambisonic soundfields at the Ambisonics'11 symposium in Paris; the article is available online at http://ambisonics10.ircam.fr/drupal/?q=proceedings/o6 Best, Markus On 17 avr. 2011, at 19:38, Dave Hunt wrote: Hi, Date: Sun, 17 Apr 2011 09:28:28 +0800 From: Junfeng Li junfeng.li.1...@gmail.com Subject: [Sursound] distance perception in virtual environments Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng Change in amplitude with distance should be perceptible fairly easily, but on its own would just sound the same but quieter, or louder. High frequency absorption by the air is only really perceptible when the distance is fairly large, though this effect could be exaggerated for artistic purposes. The lateness of arrival of sound from distant objects is not directly perceptible unless there is something visible (e.g. lightning and thunder). Reverberation definitely gives perceptible distance effects. More distant sources are more reverberant. The amplitude of the direct signal should decrease with distance (inverse square law, or some similar law), while the amplitude of the reflected and reverberant signal would remain fairly constant or decrease less rapidly with distance than that of the direct signal. It is the ratio of direct to reverberant sound that is important. John Chowning's 1971 paper The Simulation of Moving Sound Sources is a good early consideration of how to synthesise distance. Of course the reported result will depend on the listener, who may not be used to analysing sound for these effects. Ciao, Dave ___ 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] distance perception in virtual environments
That's an interesting question. The environment you're working in for synthesis could matter quite a bit. That is, if your working in, or simulating, an environment with little reverberation it is harder to judge distance since direct-to-reflected energy ratio is an important cue. The other important cue is timbre detail - especially high frequencies. But this requires the listener be familiar with the sound source to be able to discriminate. Try testing with spoken voice. I can't think of any research of the top of my head (especially for multi-channel environments). It is certainly well known that controlling high frequencies and direct/reflected ratio is important for distance perception in stereo mixing - but even there that's usually a relative, or comparative judgment, of one sound source appear vaguely 'behind' another. Not so much an absolute judgment that you might want for a virtual environment. jim On Sat, Apr 16, 2011 at 9:28 PM, Junfeng Li junfeng.li.1...@gmail.comwrote: Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/64a7d936/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- Jim Moses Technical Director/Lecturer Brown University Music Department and M.E.M.E. (Multimedia and Electronic Music Experiments) -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/5157390f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
For relatively nearby distance detection such as the buzzing bee or whispering or conversation (versus more distant sources such as in a concert hall), one needs to deliver interaural level differences on the order of 10 ot 20 dB with the corresponding ITD of up to 700 microseconds. (If the sources and speakers are relatively centered then we can ignore the pinna distance detection problem.) At the moment I believe only the Choueiri BACCH dummy head recording and crosstalk cancellation method can routinely deliver this magnitude of ILD over the full range of frequencies. If you are synthesizing the ILD in your virtual signals then you don't need to use a dummy head or an Ambiophone. Of course, this ILD seems to apply only for distances to sources at the sides of the head but in practice extreme XTC and thus real binaural ITD provides for proximity at all frontal angles in the horizontal plane as in everyday hearing. RACE, if carefully implemented with directional nearfield speakers, can get up to about 10 dB or more ILD and you might try this since it is easier (cheaper) than using any of the other crosstalk cancelling or WFS or HOA methods. There is no question that Ambiophonic users report enhanced depth perception when listening to ordinary music or the commercially available earphone type binaural recordings but you may want more than this for what you are doing so you should tweak the normal Ambiophonic methodology to optimize ILD capture and reproduction. Ralph Glasgal www.ambiophonics.org From: Junfeng Li junfeng.li.1...@gmail.com To: Surround Sound discussion group sursound@music.vt.edu Sent: Saturday, April 16, 2011 9:28 PM Subject: [Sursound] distance perception in virtual environments Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/64a7d936/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/20110417/da4e9255/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
