Testing the Testing the Human EarHuman Ear

Chris BurnsChris Burns

Johari WigginsJohari Wiggins

Frequency RecognitionFrequency Recognition

The purpose of this portion of the project is to see The purpose of this portion of the project is to see how many wavelengths of a tone it takes for a how many wavelengths of a tone it takes for a human ear to recognize that it is a tone.human ear to recognize that it is a tone.

Subjects were played 3 related tones for five Subjects were played 3 related tones for five seconds each. Then they were played selected seconds each. Then they were played selected number of wavelengths of those tones and asked number of wavelengths of those tones and asked if they could identify them. The test tones began if they could identify them. The test tones began at 1 wavelength and got increasingly longer. at 1 wavelength and got increasingly longer.

Frequency RecognitionFrequency Recognition

Results:Results:

For the low range, the average was 9 wavelengths. For For the low range, the average was 9 wavelengths. For the middle range, it was 6. For the high range, it was the middle range, it was 6. For the high range, it was 15.15.

Overall, the average number needed was 11 Overall, the average number needed was 11 wavelengths. wavelengths.

Frequency Recognition

0

2

4

6

8

10

12

14

16

18

James Matt Mike W. Tom Carroll Max Josh Ian Mike D.

Subjects Tested

Wa

ve

len

gth

s n

ee

de

d

Low Range

Middle Range

High Range

Time Delay with EarsTime Delay with Ears

Distance between ears is about 9-14 Distance between ears is about 9-14 cmcm

.12m / 340m/s = .0035 sec.12m / 340m/s = .0035 sec Used Audacity to simulate this time Used Audacity to simulate this time

delay between earsdelay between ears Time delay creates the illusion of the Time delay creates the illusion of the

sound being louder in one ear.sound being louder in one ear.

Time Delay with EarsTime Delay with Ears

Slowly increased the time delay Slowly increased the time delay starting from zero to find the starting from zero to find the threshold for the recognition of this threshold for the recognition of this time delay for the human brain.time delay for the human brain.

Found that the brain is extremely Found that the brain is extremely sensitive to time delay.sensitive to time delay.

Time Delay with EarsTime Delay with Ears

Did extensive Did extensive studies on three studies on three individuals.individuals.

Perceived Intensity Difference vs. Time Delay

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016

Time delay

59 cm

63 cm

61 cm