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speakers for single source sound detection

Started by Sylvia July 2, 2007
In single source sound localization,which speakers are better to use in
reverberant environment?Point source speakers or normal speakers.i would
appreciate any list of standard speakers used in sound localization.
On 2 Jul, 11:59, "Sylvia" <sylvia.za...@gmail.com> wrote:
> In single source sound localization,which speakers are better to use in > reverberant environment?Point source speakers or normal speakers.i would > appreciate any list of standard speakers used in sound localization.
In source localization you very seldom have the oportunity to choose the characteristics of the source. If you do, it almost always means that you have access to the source and can find its position by other means than acoustic localization techniques. So you basically have to cope with whatever is out there. Having said that, point sources are very convenient mathematical tools for modeling and analysis, as they are vanishingly small and have uniform directivity. The point source model is often valid if the source and reciever are far away form each other, i.e. when the apparent size of the source when seen (or heard) from the reciever is very small. In practice, sources are not infinitely small and have non-uniform directivity functions. These are characteristics one just have to accept and try to handle as best one can, when dealing with real-life measurements. Rune
On Jul 2, 9:06 am, Rune Allnor <all...@tele.ntnu.no> wrote:
> On 2 Jul, 11:59, "Sylvia" <sylvia.za...@gmail.com> wrote: > > > In single source sound localization,which speakers are better to use in > > reverberant environment?Point source speakers or normal speakers.i would > > appreciate any list of standard speakers used in sound localization. > > In source localization you very seldom have the oportunity to choose > the characteristics of the source. If you do, it almost always means > that you have access to the source and can find its position by > other means than acoustic localization techniques. >
Even with the increasing interest in small-area localization systems? I think that in such systems one can "design" the sound source to a larger extent than what you said. Now, interfering noise is a separate issue altogether, it's not typical that one can control it. Julius
On 2 Jul, 22:53, julius <juli...@gmail.com> wrote:
> On Jul 2, 9:06 am, Rune Allnor <all...@tele.ntnu.no> wrote: > > > On 2 Jul, 11:59, "Sylvia" <sylvia.za...@gmail.com> wrote: > > > > In single source sound localization,which speakers are better to use in > > > reverberant environment?Point source speakers or normal speakers.i would > > > appreciate any list of standard speakers used in sound localization. > > > In source localization you very seldom have the oportunity to choose > > the characteristics of the source. If you do, it almost always means > > that you have access to the source and can find its position by > > other means than acoustic localization techniques. > > Even with the increasing interest in small-area localization > systems? I think that in such systems one can "design" > the sound source to a larger extent than what you said.
Interest in a system has nothing to do with feasibility of the same system. If you cand *design* a sound source, you have at your power to include some tracking device like GPS or something like that. If the source objects (the object which makes the sound) has one of those onboard, it can report by radio its position as measured by GPS, and sound localization is reduced to merely an academic excercise. If the object is stationary, one measures its position once and use tabulated values ever after. If, on the other hand, one is interested in "sources of opportunity" -- human speakers in a conference room, mammals or submarines at sea, birds outdoor -- there is nothing one can do to "design" the source. The anatomy of ahuman being is and will remain what it is: The mouth is the main sound source and the directivity is a major factor. There is no way one can "design" a human to alter those properties, hence one can not "design" a human speaker into a point source. That's a fact one just have to accept and deal with. Of course, that doesn't prevent anyone from *modeling* the human speaker as a sound source; that way all those difficult factors like directivity functions etc disappear from the equations. The risk is that there results are wrong since posibly important aspects of the real world are missing from the mathematical model. Rune
On Jul 2, 9:07 pm, Rune Allnor <all...@tele.ntnu.no> wrote:
> > > In source localization you very seldom have the oportunity to choose > > > the characteristics of the source. If you do, it almost always means > > > that you have access to the source and can find its position by > > > other means than acoustic localization techniques. > > > Even with the increasing interest in small-area localization > > systems? I think that in such systems one can "design" > > the sound source to a larger extent than what you said. > > Interest in a system has nothing to do with feasibility of the same > system. > > If you cand *design* a sound source, you have at your power to > include some tracking device like GPS or something like that.
I doubt a GPS locator would work well for tracking a movable object in a cave, or even underwater, for instance.
On 3 Jul, 08:17, "Ron N." <rhnlo...@yahoo.com> wrote:
> On Jul 2, 9:07 pm, Rune Allnor <all...@tele.ntnu.no> wrote: > > > > > In source localization you very seldom have the oportunity to choose > > > > the characteristics of the source. If you do, it almost always means > > > > that you have access to the source and can find its position by > > > > other means than acoustic localization techniques. > > > > Even with the increasing interest in small-area localization > > > systems? I think that in such systems one can "design" > > > the sound source to a larger extent than what you said. > > > Interest in a system has nothing to do with feasibility of the same > > system. > > > If you cand *design* a sound source, you have at your power to > > include some tracking device like GPS or something like that. > > I doubt a GPS locator would work well for tracking a movable > object in a cave, or even underwater, for instance.
..which is why I added "... or something like that." GPS doesn't work underwater, but where I work we use tracking devices which are surprisingly accurate in 1000 m deep waters. Rune
On 3 Jul, 06:07, Rune Allnor <all...@tele.ntnu.no> wrote:

Bad typo needs correction:

> Of course, that doesn't prevent anyone from *modeling* > the human speaker as a -s-o-u-n-d- source;
... model the human speaker as a *point* source ...
> that way all those > difficult factors like directivity functions etc disappear from > the equations. The risk is that there results are wrong > since posibly important aspects of the real world are > missing from the mathematical model.
Rune