Sound Frequency, Wavelength, and Octaves

 

 

Sound energy is transmitted through air (or other particles) as a traveling pressure wave. In air the displacement wave amplitude may range from 10-7 mm to a few mm per second.

 


Frequency

The frequency (cycles per second) of a sound is expressed in hertz (Hz).

f = 1/T (Hz)

The range for human hearing is from 20 to 20,000 Hz. By age twelve, 13,000 Hz is the limit for many people.

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Wavelength

The wavelength of sound is the distance between analogous points of two successive waves.

l = c / f

where

c = speed of sound (m/s)
f = frequency (Hz)

 

 


Octaves

 

 

Octave

1

2

3

4

5

6

7

8

Frequency (Hz)

63

125

250

500

1K

2K

4K

8K

Wavelenght in air (m)

5,46

2,75

1,38

0,69

0,34

0,17

0,085

0,043