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| Components |
Magnets |
Sound
Waves |
Hearing Sound |
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Very simple sound waves, or waves in general, have a specific height, or amplitude, and specific wavelength. Amplitude correlates to how loud a sound is and the wavelength corresponds to the pitch of sound with shorter wavelength having higher pitches and longer wavelengths having lower pitches. Wavelengths can also be thought of in terms of frequency or how many times per second a wave goes by. This is the frequency of the wave is the common unit, called Hertz, used when referring to sound waves and the human ear can discern air vibrations between 20 Hertz and 20,000 Hertz allowing for a large combination sounds.
Image courtesy of TutorVista.com
The question remains of how out of one speaker humans can hear an entire symphony of instruments. The fact that a speaker can produce so many different sounds relies on one principle which is the superposition of waves. As can be seen in the below image, when two waves come into contact they overlap and add and subtract accordingly which is called superposition.
Image courtesy of Boundless.com and animation courtesy of Dan Russel at Pennsylvania State University
The animation can be thought of two speaker sitting opposite of each other producing a single wave which then connect to create one large wave. The image on the left shows two waves traveling in the same direction which combine together to create one more complex wave. It is the resulting combination of waves that is played by the speaker which allows for multiple sounds to be created. As more individual sound waves are added together, the resulting wave becomes more and more complex but the speaker is still move up and down according to how the complex wave moves up and down. The most amazing outcome is that human ears can still discern each individual sound, such as hearing both violins and piano from an orchestra recording.