Where are the ear-shaped microphones?
June 5, 2009 2:19 AM   Subscribe

Ears have evolved over many many years to be perfect for us to hear with. Why have I never seen an ear shaped microphone?
posted by devnull to Science & Nature (22 answers total) 1 user marked this as a favorite
Ears have co-evolved with the primary auditory cortex. Microphones don't have the same processing hardware and software.
posted by mr_roboto at 2:29 AM on June 5, 2009 [2 favorites]

Here you are. Dummy heads with or without a dummy "ear" are used in binaural and holographic recording.
posted by _dario at 2:37 AM on June 5, 2009

Most microphones are meant to pick up very specific sounds, like the voice of someone directly in front of it, and block out ambient noise. Ears are meant to pick up sounds from everywhere, not just whatever is right in front of you.

And of course, your hearing is inside your head, so sounds need to be channeled through a small opening, with microphones you have the receptor(s) exposed, and not encased in something that blocks sound.
posted by bjrn at 2:53 AM on June 5, 2009 [1 favorite]

Dummy heads with or without a dummy "ear" are used in binaural and holographic recording

Or you can use your own head instead, by using these microphones. I have a pair, and if you have headphones on your computer, a one minute sample soundfile (.mp3) I made while walking down the street outside my home is a pretty good demonstration of just how effective they are. (If you don't have headphones, don't bother, as the effect is lost through external speakers ...)
posted by woodblock100 at 3:15 AM on June 5, 2009 [9 favorites]

To enjoy a recording made with an 'ear microphone' (like a binaural set), you need headphones, or else, the panning and filtering are gone.
posted by ddaavviidd at 3:19 AM on June 5, 2009

Ears have evolved over many many years to be perfect for us to hear with.

Actually, no. Ears have evolved over many of millions of years based on evolutionary pressures experienced by humans and their line of ancestors, and those pressures have been consistent in neither intensity nor kind. Moreover, ears may continue to change going forward based on yet different evolutionary pressures. So the ears we have now are not perfect. Rather, our ancestors' ears worked well enough to become what we have today, and each generation's ears were constrained in form and function by the genes inherited from the previous generation (excepting mutations). Well enough in this context means "kept from dying," so our ears don't necessarily offer true engineered audio fidelity, but rather enough sound to keep us alive. Hearing the pedals on a piano recording probably pales in importance to hearing a lion in the brush far off on the savannah.
posted by The Michael The at 4:13 AM on June 5, 2009 [29 favorites]

The ear-shaped microphones are there to make recordings designed to be listened to with headphones (preferably in-ear types) only. Such recordings are really interesting to listen to, because you really can hear a full 3D sound space even though there are only two channels in the recording. But the market for such recordings has historically been a fairly small niche, since most recorded sound has been experienced via loudspeakers. Listening to ear-microphone sounds via loudspeakers effectively puts two lots of external ears in series (those on the mikes and those on your head) and you don't experience that as a 3D soundspace.

Now that increasing numbers of people are listening to most of their music via portable music players with ear buds, I expect that ear-shaped microphones will make a bit of a comeback. But I don't think it will happen bigtime until bandwidth has become cheap enough that FLAC displaces MP3 as the ubiquitous audio file format. Part of what makes ear-shaped microphones able to do their magic thing is the phase relationships they set up between similar-frequency signals in each channel, and phase relationships are one of the things that MP3 and similar lossy compression formats lose.
posted by flabdablet at 4:32 AM on June 5, 2009 [3 favorites]

An ear-shaped microphone is called a parabolic microphone.
posted by XMLicious at 4:38 AM on June 5, 2009

The Michael The is absolutely right. Never assume that a structure is perfect just because it evolved that way. It bears repeating that evolution makes things that are good enough for there particular environment, NOT perfect.
posted by Midnight Rambler at 4:41 AM on June 5, 2009

Ditto mr. roboto, The Michael The, and Midnight Rambler. Don't get all Panglossian:
It is demonstrable that things cannot be otherwise than as they are; for as all things have been created for some end, they must necessarily be created for the best end. Observe, for instance, the nose is formed for spectacles, therefore we wear spectacles.
posted by kestrel251 at 5:52 AM on June 5, 2009

Ears have evolved over many many years to be perfect for us to hear with.

Even if you look at evolution as a kind of optimization process, ears get optimized for things other than just hearing ability. Just for example: resistance to infection, exposure to injury, attractiveness to the opposite sex, or suitability for environmental conditions. So you see microphones in other shapes because they are optimized for different things.

Although I guess depending on the marketing strategy of the product, microphones might also get optimized for attractiveness to the opposite sex. ;)
posted by FishBike at 6:05 AM on June 5, 2009

While ears' primary function is to hear, they have to do it in a way that doesn't make us sick or hurt or slow or dumb or whatever. In other words, there are other evolutionary pressures besides those just on hearing that go into developing ears.

(or on preview what FishBike said!)
posted by bluefly at 6:38 AM on June 5, 2009 [1 favorite]

Additionally, think of it this way - the human ear emphasizes a certain set of frequencies (mostly those in which human speech takes place). If microphones were built to emphasize the same set of frequencies, those frequencies would have even more emphasis. Instead, the "best" microphones are built to sound as transparent as possible, with very little deviation from a flat frequency response.

Okay, it's not strictly true that the "best" mics are close to flat, but it's close enough for this discussion
posted by god hates math at 6:49 AM on June 5, 2009

The external part if the ear, that ruffle of cartilage, is the pinnal flap. As others above have said, don't be deceived into thinking we have "perfect" ears -- they are not even really all that great compared to a lot of other mammals: deer and cats, for example, can swivel the whole affair around to focus on one spot and boost perceived sounds form that spot by effectively 20-30 decibels while blocking out other sounds. We poor apes have to cup our hands around the ear to get anything like this effect.
posted by ricochet biscuit at 6:53 AM on June 5, 2009

I had a friend who did some of the sound recording for Microsoft Train simulator and he had a recording device shaped like a head with ears.
posted by jessamyn at 7:18 AM on June 5, 2009

a recording device shaped like a head with ears

They are called 'Kunstkopf' ... lots of information on them here ... or you can always build your own!
posted by woodblock100 at 7:31 AM on June 5, 2009

The UK TV program "Tomorrow's World" once did a demonstration where they made some model ears and attached them to people's hands - then fed the signal to the people's actual ears. They then pitted some hand-ear people against normal individuals on the task of finding an auditory target. The hand-ear people did a lot better than the others. As ricochet biscuit points out above the fact that we are unable to swivel or move our ears independently of our head makes them only mediocre at detecting the source of sounds.
posted by rongorongo at 7:47 AM on June 5, 2009

The shape of the human ear introduces some distortions into the sound. These distortions will depend on the direction the sound is coming from. That is, the same sounds from strait up will reflect on different bits of cartilage than the sound coming from bellow, and they will sound a tiny bit different. The brain picks up on these distortions and interprets them, which give us the ability to sense the location of a sound source in 3D location, rather than simply as a left or right. If we only had phase shifts and volume to tell the direction of sound, we wouldn't be able to tell up from down, or back from front.

To reproduce full 3d, you either need a no-ear microphone and a with-ear listener (standard mike with loudspeakers), or the reverse, a with-ear microphone and a no-ear listener (holographic mike with earphones). The industry has standardized on the former because more music is listened to on speaker than on earphones, and that until recently speakers had always reached higher levels of fidelity then earphones.
posted by gmarceau at 8:01 AM on June 5, 2009

And also because the former works better than the latter. You can ear 3d better when you are using your own ear, since your brain has learned its particular shape.
posted by gmarceau at 8:05 AM on June 5, 2009

Building on what The Michael The said, why would it be based on human ears?

Why not base your hypothetical mic on an animal that hears better than us? Like a microphone based on bunny ears. They hear much better than us and can rotate their ears to pick up sounds from various directions.

Also, the microphone would be very cute.
posted by drjimmy11 at 8:40 AM on June 5, 2009 [4 favorites]

Microphones don't have to be made of jelly and cartilage. Also, as noted above, evolution doesn't care about "perfection", only multi-goal optimisation for the purposes of increasing reproductive fitness. Finally, unlike the rather simple and atomic design constraints for microphones, many of the rather obscure genes coding for ear phenotypes are linked together and cross-linked with facial phenotype genes (see, for instance, the classic Y-chromosome inheritance of hairy ears) and thus the expression of different traits can exhibit a mixed sex-linked and polygenic autosomal inheritance pattern.
posted by meehawl at 10:09 AM on June 5, 2009

Why have I never seen an ear shaped microphone?

Good answers are above. Also, if an ear were shaped like a microphone, it would be a rather fragile device outside your head (or the head of whatever animal)--easily chewed off by predators or hacked off by competitors. It makes sense that, in the long run, it's better to have the fragile stuff protected inside a thick skull where it can still function to some degree if the floppy bit (that must necessarily be external) gets removed.

(And you may have noticed that ears bear a certain resemblance to satellite dishes and other such antennae.)
posted by K.P. at 12:08 PM on June 5, 2009

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