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"These flies have highly specialized ears that provide the most acute directional hearing of any animal," says Andrew Mason, a professor of biology at U of T Scarborough. "The mechanism that makes their hearing so exceptional has even led to a range of bio-inspired technology, like the mini directional microphones used in hearing aids."
[... W]hat makes the fly truly remarkable is its mechanically-coupled ears. Unlike most animals that have two separate ears, both of Ormia's eardrums are connected together, kind of like a seesaw with a rigid joint in the middle that can bend. When one of eardrums vibrates from a sound wave it pushes the other, and the tiny time difference it takes to activate one ear drum allows the fly to figure out which direction the sound is coming from.
"It's interesting that something so small can be sensitive to the direction of sound," says Mason. "They're tiny relative to the wavelength of sound they're able to localize, so they shouldn't be able to do what they do but they can because of the mechanical coupling."
Engineers are interested in using the same principle found in Ormia's coupled eardrums to develop artificial sensors. These sensors could better locate signals for a range of uses where the size of the object relative to the signal might be a limiting factor -- from hearing aids, to gunshot detectors, to different types of radar.
-- submitted from IRC
(Score: 3, Interesting) by ikanreed on Tuesday May 16 2017, @06:35PM (7 children)
The structure of the (inner) ear is kinda fascinating to me. The hair follicles of decreasing length in a spiral cavity act a lot like a mechanical Fourier transform, where each follicle corresponds to a specific pitch.
That, in turn, acts like a perfect input to a neural network, a series of distinct magnitudes.
The way the article describes the fly, it's great for directional discrepancies, but it sounds like it wouldn't actually be good for that core filtering that makes humans able to process and interpret language(i.e. most of what we use our ears for)
(Score: 2) by kaszz on Tuesday May 16 2017, @07:29PM
Maybe one can design a speaker the same way. One acoustic emitter for each frequency?
And I know it's a hard design..
(Score: 3, Interesting) by dak664 on Tuesday May 16 2017, @07:54PM (3 children)
Ever since ATSC video transmission when I am completely relaxed and there is a low level source of white noise (wind or ceiling fan) I can hear dialogue on the strong local TV station, particularly early morning and late evening weather reports. Just a couple KHz bandwidth, enough to distinguish the different voices and maybe 1/5 of the words. I have no idea how I could be decoding the AC3 bitstream of a constant amplitude RF signal, but possibly there is some FM audio component when there is a low video bit rate of a talking head.
Makes me wonder what other communications might be discoverable. Others have had the same idea http://www.rhine.org [rhine.org]
Of course most would dismiss this out of hand as batshit crazy.
(Score: 3, Interesting) by edIII on Tuesday May 16 2017, @08:52PM (2 children)
You're not crazy. I can hear radio stations in my head. By hear, I don't mean hear the words or music or anything, but I'm perceiving it. How do I know? I start singing the damn song :)
What I found was that when that feeling came, I could turn the radio on and find the song. A few times, the song in my head matched the radio to the extent that I was nearly perfectly aligned with the song. That was weird and pretty cool.
My take away from that is that we don't really understand what a human is capable of perceiving. Many animals, which by the way I think they meant insect, demonstrate the ability to sense magnetic waves through a symbiosis with small bacteria that are sensitive to it. It's how birds are able to navigate so well. I fully believe that human beings are perceiving these things to some extent, and you only need a few cues and memories triggered before you are signing a song.
It's like Whistler from Sneakers hearing the whine in the emergency lights that nobody else can hear.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 0) by Anonymous Coward on Wednesday May 17 2017, @01:44AM (1 child)
You're not crazy. I can hear radio stations in my head.
Yeah he is, and so are you. I know who you all are. You go around the office all day singing *You are the apple of my life...* The least you could do is tune into a different station. Get the filling replaced, whatever it takes...
(Score: 2) by edIII on Thursday May 18 2017, @12:59AM
Fuck you. I already told you that I can sing at a reasonable volume until 11am. You keep messing with me and I'll set the building on fire.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 5, Informative) by AthanasiusKircher on Tuesday May 16 2017, @08:57PM (1 child)
The hair follicles of decreasing length in a spiral cavity act a lot like a mechanical Fourier transform, where each follicle corresponds to a specific pitch.
Not to be too pedantic, but there's a little more to it. Frequencies are mostly detected by the basilar membrane [wikipedia.org] in the cochlea, which is tapered and thicker at one end, causing each region to be vibrate somewhat differently. Yes, the "hair cells" pick up on these vibrations and transmit them to auditory nerves.
It's also important to note the difference between "pitch" and frequency here. Pitches are a mental construct, which only really are created in the auditory cortex. All sorts of weirdness in terms of perceived pitch can happen depending on the sensitivity of the basilar membrane at various frequencies (and how "spaced" the "hairs" are), as well as the distribution of harmonic patterns within the set of perceived frequencies (which are used to produce the main "fundamental" that is usually identified as the "pitch"). Perhaps the most commonly known phenomenon is the missing fundamental [wikipedia.org] effect, which actually allows many small speakers like phones to work. Small speakers can't often reproduce low frequencies, and I don't know if this is true anymore, but standard phones used to not be able to even produce ANY sounds in the range of the male voice fundamentals. The ONLY thing you'd actually hear were higher frequencies, but your brain supplies the missing fundamental to hear a much lower pitch.
So, not only does the ear perform something like an FFT, but the brain then performs a reconstruction of what the sounding object is likely to be and supplies all sorts of missing information. The missing fundamental is only the most well-known of this sort of thing. Other higher-level processing does all sorts of fun stuff to the audio signal (some of which makes for some pretty odd auditory illusions).
(Score: 3, Insightful) by ikanreed on Tuesday May 16 2017, @09:04PM
Always upvote thorough science, I say.