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Author Topic: What fun things can you do with your ears?  (Read 3868 times)

Offline cheryl j

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What fun things can you do with your ears?
« on: 28/12/2014 13:23:19 »
I teach anatomy and when we get to the sensory systems, I like to provide my students with different experiments they can do in class or at home that help demonstrate certain aspects of function or are just plain fun and weird. I have lots of stuff on optical illusions and touch, but not much with hearing or smell.

I've been playing around with things recorded on binaural microphones - boy is that ever weird. And it's weird because it's so normal - that is, it really mimics the way our ears hear compared to a variety of noises being emitted from a single source, like when you are watching tv, or even stereo in a room.

I was surprised at how the binaural sounds made me feel as if something or someone was really "present" - behind me or a certain distance away, so much so that I occasionally had to remove the ear buds because when I heard a door open or the rustling of clothing, I thought some one had come into the room.

I also find it interesting because of comments my husband made. He lost hearing in one ear due to a virus. He says it hasn't impacted the volume of what he hears as much as it has affected his ability to tell where sound is coming from. I noticed this too. When someone he can't see calls to him, he almost always looks in the wrong direction first.

Anyway, if you know of any fun binaural experiments, demonstrations or illusions, please respond.



« Last Edit: 28/12/2014 13:35:41 by cheryl j »


 

Offline evan_au

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Re: What fun things can you do with your ears?
« Reply #1 on: 31/12/2014 12:07:18 »
A couple of random ideas:
1. Human Echolocation
Some blind humans use acoustic echo-location to detect obstacles.
We are familiar with the ability of bats to capture insects by supersonic echolocation. Human hearing does not extend that far in frequency, but sounds we can make and detect allows humans to detect walls and larger obstacles - a skill that has been discovered and used by a number of blind people.

As I understand it, this could be demonstrated by finding a flat area with no trip hazards, and  a sound-reflective surface like a brick or concrete wall on one side. Blindfold the test subject without blocking their ears.

They then click with their mouth or fingers or even by tapping two sticks or two rocks together, as they walk towards the wall; the goal is to practice stopping as close as possible to the wall without touching it. A non-blindfolded assistant is present to ensure they don't injure themselves.

Other challenges could be to detect an open door in the wall, and walk through it.

2. Sounds Produced by Your Ears
This is a bizarre auditory effect that should be accessible in class with the right laboratory equipment: otoacoustic emission.

It is the sounds generated by your ear as it attempts to detect sound waves in the environment.

 
 

Offline evan_au

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Re: What fun things can you do with your ears?
« Reply #2 on: 31/12/2014 21:31:14 »
...and a few more suggestions, after sleeping on it:
3. Hearing Test
Today's hearing tests seem computer-driven, highly automated, quick, and produce a printable report. Understanding your own hearing is a good first step to understanding someone else's hearing. The anatomy students could take the test, then test one of their classmates.
The audiology department might be prepared to let the anatomy students use their equipment, but the interpretation might be a bit lacking (it helps if you understand deciBels, dB). Alternatively, the audiology department might consider it a useful practical exercise for the audiology students to test all the anatomy students?

This test might start to show the impact of listening to personal music players for 15 years before reaching university...

4. Try Bone Conduction
It is said that after Beethoven went deaf (starting around age 26), he composed his music with a pencil clenched in his teeth, and pressed against the wooden frame of the instrument. Sound traveled through the instrument, through the pencil, through his jawbone and was able to reach the middle ear via that route.

A similar effect can be achieved by clenching a pen in your teeth. The ear canal can be blocked with earplugs (large hardware shops sell bulk packs of earplugs quite cheaply).  A loudspeaker box attached to an MP3 player should provide a good source of vibrations (just don't use the university's grand piano - they might not be impressed).

5. Make an Ear Trumpet
Before the invention of the electronic hearing aid, people with hearing problems used a passive device called an "ear trumpet".
You can easily make one by rolling a cone out of a single sheet of printer paper and holding it together with a bit of sticky tape (eg here).

The ideal cross-section approximates an exponential, but that is more than 5 minutes work with a sheet of paper and sticky tape!

6. Simulate the effect of the Virus
You could simulate your husband's unfortunate hearing loss by sitting a blindfolded person on a chair (ensure their ears aren't covered).

The blindfolded person covers their ears and counts up to 10, while their partner moves to a position perhaps 3m away, in a random direction. The blindfolded person uncovers their ears, and their partner says something. The blindfolded person points at where they think the sound is coming from.

You could try a few variations:
  • Short utterances (eg The next letter of the alphabet; A to F have a mix of vowels, consonants & fricatives)
  • Longer utterances (eg "The cat sat on the mat").
  • Longer utterances, but physically holding your head still (we unconsciously turn our heads to help localise the sound).
  • Only uncover one ear.
  • You could make it quantitative by dividing the space into (say) 45 degree, numbered segments. The partner stands in the center of a random segment to make the noise, and then records which segment they were in, and which segment the test subject pointed to.

I ran across this educational site while looking for ear trumpets: http://www.cafemuse.com/soundgarden/perception.htm
 

Offline RD

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Re: What fun things can you do with your ears?
« Reply #3 on: 01/01/2015 02:45:23 »
I have lots of stuff on optical illusions and touch, but not much with hearing or smell.  illusions ... please respond.

The McGurk effect is audio-visual illusion ...
« Last Edit: 01/01/2015 02:52:45 by RD »
 

Offline cheryl j

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Re: What fun things can you do with your ears?
« Reply #4 on: 01/01/2015 21:50:58 »
Thanks. Those i great ideas. Its interesting too how good we are at detecting and remember particular types of sounds. We know what it sounds like when someone is putting silverware away in a drawer, or the particular kind of paper being crinkled, the sound of the clothes drier being open or shut.  Some people have distinctive foot steps.
 

Offline RD

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Re: What fun things can you do with your ears?
« Reply #5 on: 02/01/2015 06:39:13 »
I have lots of stuff on optical illusions and touch, but not much with hearing ... Anyway, if you know of any fun binaural experiments, demonstrations or illusions, please respond.

Infinitely rising Shepard tone ...
http://www.freesound.org/samplesViewSingle.php?id=65591
« Last Edit: 02/01/2015 06:42:31 by RD »
 

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Re: What fun things can you do with your ears?
« Reply #5 on: 02/01/2015 06:39:13 »

 

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