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Son of Where's that noise coming from

  [vote for,

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...)

MaxwellBuchanan, May 27 2015

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]

Sonic Partial Panorama experiment https://www.youtube...watch?v=m7w-jr5xpRA
I suspect the channels are crossed over (in encoding my four channels into 5.1 channels uploading to youtube with surround having priority over stereo) [Ian Tindale, May 28 2015]

Another Sonic Partial Panorama experiment https://www.youtube...watch?v=e0Lw_Fqq8O4
I still suspect the channels are crossed over (in encoding my four channels into 5.1 channels uploading to youtube with surround having priority over stereo) [Ian Tindale, May 28 2015]

Gallions Point mud binaural stereo with action cam https://www.youtube...watch?v=bMcIMOxM8_U
A binaural stereo + action cam video recording I made last summer — use headphones, or (and here’s an innovation of mine) if you have speakers either side of your monitor, point them outwards instead of toward you, thus forming a stereo dipole arrangement, to get the binaural effect in free space. [Ian Tindale, May 28 2015]

Nifty, inappropriate http://io9.com/stud...-and-sou-1693561917
replacement for ear buds [4and20, May 29 2015]

Generating spatial audio from portable products - Part 2: Acoustic beamforming using the LM48901 http://www.eetimes.....asp?doc_id=1279486
[Ian Tindale, Jun 13 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]

Quasonama http://u0421793.github.io/quasonama/
This is the culmination of all that guff I was on about earlier last year and the year before. My idea Quasonama is a feasible approach to modern immersive audio. Should be good for VR too. [Ian Tindale, Feb 19 2016, last modified Apr 29 2016]

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]


       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.
4and20, May 27 2015

       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.
xenzag, May 27 2015

       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).   

       Or Mike Murdock (Daredevil) can do it.
bhumphrys, May 27 2015

       Isn't sound (pressure) a scalar field? How do you measure the direction of a sound at a point in space?
EnochLives, May 27 2015

       Actually a cell phone might be better at locating some noises than human ears if they can detect higher frequencies.   

       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.   

       This app should run continuously for a long time and add a new sound to the list whenever one is recorded.
scad mientist, May 27 2015

       //How do you measure the direction of a sound at a point in space?// You don't. Phones nowadays have two microphones.
MaxwellBuchanan, May 27 2015

       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.
Custardguts, May 27 2015

       //You don't// unless you have a tube you can put the mic in.
FlyingToaster, May 27 2015

       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.
RayfordSteele, May 27 2015

       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).
hippo, May 28 2015

       Last year I spent a lot of the summer developing a new format for hemi-panoramic sound in four channels. I also did a lot of binaural experimentation. I’ll post an example of binaural recording using two channels, but when played back can sound quite spatially discriminatory. The way binaural spatial recording works utilises the HRTFs of our head (head- related transfer functions). This can be artificially synthesised by filtering and delaying individual sound source signals to simulate directionality of a sound in a soundscape when received by each individual ear.   

       I uploaded a few experimental videos last year with surround sound as well as stereo, but youtube is insufficiently developed to handle surround properly (I suspect it crosses over the channels incorrectly when making its own stereo mix-down in its own encoding). The recordings of planes etc were done using four channels (a pair of stereo audio recorders — i.e., two Zoom H1 recorders, later synchronised in Final Cut Pro X, which is what I spent a lot of last year in, when I wasn’t in Logic Pro X or Motion). Although I recorded in four channels, my new format isn’t widespread (it’s only really gained popularity in my own living room, and garden), and so I had to map the four channel arrangement into 5.1 surround, which is more commonplace, in order to upload for youtube (which I suspect doesn’t even assign the channels properly).   

       There’s several 5.1 surround channel numbering arrangements in use, for channels 1,2,3,4,5,6:   

       5.1 WAV — FL FR FC LFE SL SR

       So as you can see, everything’s perfectly unambiguous and should work first time no matter what technologies and processes anyone in the world should choose to use, can’t see any reason at all why things should ever get mixed up, pretty sure that’ll never happen, not at all.   

       Last year I also realised that stereo speakers on computers either side of the monitor, when turned to face outward instead of toward you, can form a stereo dipole and will give you a reasonably effective binaural effect without having to use headphones (although better if you do use headphones).
Ian Tindale, May 28 2015

       //everything’s perfectly unambiguous and should work first time no matter what technologies and processes [...]//   

       Thank you for the belly laugh, [Ian Tindale].
pertinax, May 28 2015

       ////You don't// unless you have a tube you can put the mic in.//   

       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.   

       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.   

       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.   

       So, to clarify and eliminate any residual doubt - the idea depends on there being TWO microphones in most modern phones.   

       Further clarification available on request.
MaxwellBuchanan, May 28 2015

       The Nokia 920 I briefly tried out (for video purposes — not bad as a camera, with optical stabilisation, but a ridiculous operating system) has three mics.   

       My Sony camcorders that have surround sound recording also have a three mic array, to generate their six channel Dobly surround audio. !
Ian Tindale, May 28 2015

       I wonder how many ears the people who design these six-speaker systems expect us to have?
MaxwellBuchanan, May 28 2015

       That’s nothing — search for “22.2 surround sound” to do with Super Hi-Vision.
Ian Tindale, May 28 2015

       Incidentally, that’s quite a common fallacy, people saying “well, I’ve only got two ears so why would I need more than two speakers?”. The initial developments of what we now call “stereo” were not using two but more commonly three channels. A sound field that allows spatial discrimination may well be able to be achieved using only two channels, but a better sound field can be created more effectively with more channels.   

       The experiments in the 60s and 70s with quadrophonic/quadraphonic were a failure not because we don’t need four channels, but because
a] they were encoded onto two-channel audio and decoded into four channels,
b] there were competing formats for these encoding methods, mostly incompatible, none of them easily allowing discrete four channel distribution,
c] most of them encouraged putting a speaker in each corner, which is the worst possible arrangement of four channel, leaving wide perceptual ‘holes’ in the sound field between each channel. They’d have been better off using a diamond format (both at the recording origin and at the speaker arrangement), but in fact there are better arrangements than that.
Ian Tindale, May 28 2015

       [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.   

       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.   

       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?
bhumphrys, May 28 2015

       //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//   

       Is this sort of thing used for counter battery direction/ranging in artillery fire control?
bs0u0155, May 28 2015

       I can't see why not. But you would need to be careful not to fart near the microphone.
bhumphrys, May 28 2015

       // speew the phone about say a vertical axis,   

       Sounds unhygienic and/or physiologically impossible.   

       I think the gunfire location wotsit used in Northern Ireland was 'Ptarmigan', but I'll be buggered if can find any references to it..
not_morrison_rm, May 28 2015

       //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.
MaxwellBuchanan, May 28 2015

       [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.
hippo, May 29 2015

       <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.
not_morrison_rm, May 29 2015

       //counter battery direction/ranging in artillery fire control?//   

       Back in the 80s I think they used radar for that, not sound - anyone remember ArtHuR?   

       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.   

       "I can tell you with some certainty it's coming fr [transmission interrupted]"
pertinax, May 29 2015



       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   

       Does make you wonder why the churches never bid for [whatever cellular telephony is called where your live] base stations..lack of aspireation?
not_morrison_rm, May 29 2015

       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.   

       To locate sounds in 3D, the phone will need one of the following:   

       1. Four or more microphones, not all in the same plane   

       2. Two (or maybe even just one) microphones, and knowledge of its phone-related transfer function(s)   

       3. To be moved/rotated as it listens with two microphones   

       All of those are achievable. I expect the app to be launched within the year.   

       // Isn't sound (pressure) a scalar field? How do you measure the direction of a sound at a point in space? //   

       Because sound has a finite speed. Look up microphone arrays, beamforming, particle velocity probes, etc.
notexactly, Jun 13 2015

       Acoustic beamforming is particularly interesting, as implemented commercially. The more sophisticated and expensive soundbars for insufficiently-endowed televisions use beamforming techniques quite impressively. Cheaper low-end soundbars are merely long boxes with a pointless amount of small speakers in.   

       See the link I posted all the way up there (so far up the page it’s hard to believe it’s related to this comment, as if it’s in another country): Generating spatial audio from portable products - Part 2: Acoustic beamforming using the LM48901
Ian Tindale, Jun 13 2015

       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.
notexactly, Jun 15 2015

       My prior art links are just for linking related ideas together, not to suggest that this should be deleted.
notexactly, Nov 14 2015

       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?
not_morrison_rm, Feb 26 2017


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