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Re-encountering the linked idea, I thought at first it would be
for something else. But it wasn't. So this is.
Phones now generally have at least two microphones (for
noise cancellation), and are full of complex gubbins. This
should make it possible to build an app that tells you where a
noise is coming from.
The app would listen to incoming sounds, and identify the
main components (for example, sounds which recur
periodically like a ticking clock; and the main pitch
components of continuous sounds like a whistling or
humming). It would then list these on screen and replay any
one of them on request, so you could tell that, for instance
"Sound number 3" is the low-pitched whistle that's annoying
you.
The phone ought then to be able to tell you which direction
that particular sound is coming from, based on phase
differences between its two microphones.
(I'm getting deja vu all over again about this idea, so maybe
it's been done...)
The idea that wasn't this one.
Where_27s_20That_20Noise_20Coming_20From
[MaxwellBuchanan, May 27 2015]
Acoustic intensity
http://www.google.c...4XETqSKA_xTXm6Xtv3w
Description of how to visualise sound fields [bhumphrys, May 27 2015]
Prior art...
Pop-up_20Sprinkler_...d_20Laptop_20Camera
[normzone, May 27 2015]
http://en.wikipedia...iki/Gunfire_locator
[hippo, May 28 2015]
Nifty, inappropriate
http://io9.com/stud...-and-sou-1693561917
replacement for ear buds [4and20, May 29 2015]
Prior art
Sound_20Source_20Locator
handheld hardware device with laser designator [notexactly, Nov 14 2015]
Prior art
Audio-based_20Sniper_20Source_20Locator
helmet-mounted device for soldiers [notexactly, Nov 14 2015]
Prior art
Find_20Snipers
fixed installation, noted to be double-pre-baked [notexactly, Nov 14 2015]
Prior art
Sensound_ae
hardware device intended for blind people [notexactly, Nov 14 2015]
Directed Energy Precipitation Stimulation
https://hackaday.io...itation-stimulation
And the thing I was on about last year. [notexactly, Feb 20 2016]
Prior art
Noise triangulator
Just discovered [notexactly, Feb 26 2017]
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Annotation:
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There was a famous Canadian novelist, half deaf, who went trekking down train tracks and was hit by a train he didn't hear. For everyone else I imagine that ears are better at localizing than apps. |
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How about "where's the noise of that coming from?" for when you bothered by noisy love making late at night and don't know who's doing it. |
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Sound is a vector field. You can measure the dierction as well as the magnitude at any point in space, and by combining the output of a sound intensity probe with a pressure level map you can infer the origins of sound (see link). |
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Or Mike Murdock (Daredevil) can do it. |
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Isn't sound (pressure) a scalar field? How do you measure
the direction of a sound at a point in space? |
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Actually a cell phone might be better at locating
some noises than human ears if they can detect
higher frequencies. |
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I was in a house that wasn't mine and started
hearing a fairly high pitched beep about once
every minute, but the pitch and the fact that
there was a long time between beeps made it
incredibly difficult to find. We basically had to
move around and try to figure out if it was louder
this time or the previous time. It turned out to
be the refrigerator warning us that the door was
ajar. |
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This app should run continuously for a long time
and add a new sound to the list whenever one is
recorded. |
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//How do you measure the direction of a sound at a
point in space?// You don't. Phones nowadays have
two microphones. |
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Well, given that phones these days have a dizzying array of inclinometers and accelerometers - you could probably get this thing to the point that you could speew the phone about say a vertical axis, and it could, by knowing the position and orientation of both microphones, determine fairly precisely the direction if not range of the noise source. |
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//You don't// unless you have a tube you can put the mic in. |
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I had an Aureal 3d sound card back in the day. It was
incredibly good at reproducing sounds to create the effect
of where they were coming from, using only stereo
headphones. Sounds above and below you in the same
vertical plane would theoretically arrive at your ears at the
same time, but the quality and pitch were manipulated in
such a way as to mimic the differences that allow us to tell
when a sound is either directly above, ahead, behind, or
below. This work they did should seem to have some
application here. |
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I'm pretty sure this has been used to pinpoint the location of gunshots in cities - with microphones spread out over a city centre, you can, in theory, triangulate a gunshot sound (see link). |
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//everything’s perfectly unambiguous and should work first time no matter what technologies and processes [...]// |
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Thank you for the belly laugh, [Ian Tindale]. |
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////You don't// unless you have a tube you can put
the mic in.// |
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Perhaps when I mentioned that most phones have
two microphones, I wasn't being clear enough. For
clarity - most phones have microphones, and there
are two of them. Two. One, and then another one.
Like two cups of coffee, but with microphones. |
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Two microphones enable you (in theory) to tell the
direction from which the sound is coming from, based
either on relative sound intensities (iffy) or timing
delays between the two mics. |
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If you are the fortunate possessor of a full set of ears
(i.e., two; one plus one), you probably already know
that you can estimate the direction from which a
sound is coming. People with one ear have much
more difficulty doing this. People with no ears
cannot do it at all. |
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So, to clarify and eliminate any residual doubt - the
idea depends on there being TWO microphones in
most modern phones. |
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Further clarification available on request. |
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I wonder how many ears the people who design these
six-speaker systems expect us to have? |
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[Enoch] yes the news that sound is a vector field amazed me too. But Brüel & Kjær, for example, offer training courses in the topic of sound intensity measurement and will also sell you an acoustic intensity probe and associated calibration equipment in order to be able to measure it. |
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At the position where it is set up, the probe measures the gradient of sound pressure in three directions, for example left-to right, back-to-front and up-and down. One technique of doing this is to set up three pairs of microphones, the microphones in each pair being very close together. The small distance between the microphones in each pair is known. Because the microphones are individual pressure sensors if you connect the electrical outputs together with opposite polarity the output represents the pressure difference between the two. This represents the 'gradient' of the pressure field in the direction along which the microphones are spaced. So with the six microphones,the gradient of pressure in all three directions is known. Together with the actual sound pressure level from the microphones, all the information about the sound field is then known. |
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The sound field at each point in space is the vector sum of the sound field from each emission source, or sink. Yes we've all heard of sound sources, but the idea of a sound sink is quite interesting isn't it? |
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//So with the six microphones,the gradient of pressure in
all three directions is known. Together with the actual
sound pressure level from the microphones, all the
information about the sound field is then known// |
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Is this sort of thing used for counter battery
direction/ranging in artillery fire control? |
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I can't see why not. But you would need to be careful not to fart near the microphone. |
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// speew the phone about say a vertical axis, |
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Sounds unhygienic and/or physiologically impossible. |
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I think the gunfire location wotsit used in Northern Ireland was 'Ptarmigan', but I'll be buggered if can find any references to it.. |
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//the idea of a sound sink is quite interesting isn't
it?// Interesting, but not surprising. I have taught
students who absorb wisdom in much the same way
that black hole absorbs light or a dog absorbs biscuits
- i.e. with unlimited capacity but a complete inability
to emit the absorbed item in any useful form. |
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[Ian] I saw a demo at the BBC of some of the 2012 Olympics coverage in Super Hi-Vision with 22.2 sound - just amazing. They made the point that the technology was provided by NHK who did a similar demo of HD television at the 1984 Olympics. |
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<hiding to nothing>Super Hi-Vision with 22.2 sound </hiding> as whatever superscreen and/or sound system the makers create will most likely be publicised to the public on tv, on their own bog standard tv's. |
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//counter battery direction/ranging in artillery fire control?// |
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Back in the 80s I think they used radar for that, not sound - anyone remember ArtHuR? |
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I'd guess that when you're trying to track down a howitzer, not a sniper, you probably don't have a line of sight to the source of the sound. Then, several miles of intervening objects might change the apparent direction of the sound - especially in an environment where there are many similar loud bangs. Radar, on the other hand, can get a line of sight to the projectile in flight, and then, so to speak, doodle a leisurely parabola on a sketch pad. |
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"I can tell you with some certainty it's coming fr [transmission interrupted]" |
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They mostly have tall spires, ideal for placing microphones for triangulating sounds. Or Church-Net for that matter, as they also have line of sight of each other for microwave transmission. I hear the reception is divine, inspireing etc |
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Does make you wonder why the churches never bid for [whatever cellular telephony is called where your live] base stations..lack of aspireation? |
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I've been thinking about this kind of thing for a while
as a feature for my (nonexistent) smart
glasses/headband. I never thought of it as a phone
app, but I suppose that would be useful for people
without said smart glasses/headbands. |
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To locate sounds in 3D, the phone will need one of
the following: |
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1. Four or more microphones, not all in the same
plane |
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2. Two (or maybe even just one) microphones, and
knowledge of its phone-related transfer function(s) |
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3. To be moved/rotated as it listens with two
microphones |
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All of those are achievable. I expect the app to be
launched within the year. |
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// Isn't sound (pressure) a scalar field? How do you
measure the direction of a sound at a point in space? // |
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Because sound has a finite speed. Look up
microphone arrays, beamforming, particle velocity
probes, etc. |
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Generating beamformed audio is actually necessary for
an idea I had recently, so thanks for the link. After
looking at the datasheet, I think that part just might be
suitable for my idea. I don't need any of the HRTF or
stereo stuff though. I just need to produce the greatest
sound pressure and/or particle displacement possible at
1–5 km range. (The array will be large. And no, this isn't
going to be a sonic weapon.) I will try to remember post
a link here when I post said idea. |
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My prior art links are just for linking related ideas together,
not to suggest that this should be deleted. |
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Could be useful for my invisible animal syndrome, I can hear them, but they are behind a wall or something...or is it just me? |
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