Waves and Harmonics


 Overview:

The distance between peaks in a sound wave is called the “wavelength.” Shorter wavelengths correspond to higher frequencies and are heard as higher pitches. 

Sounds from different sources sum to produce what we hear. In each of the waveform graphs below, the top two lines represent different pure tones and the bottom (blue) line represents the sum. What you hear depends on how the waveforms are aligned: When their peaks and troughs are aligned as in the top figure (termed “in phase”), the sum is larger and the resulting tone is louder. But when the peaks and troughs of the two waveforms are completely mis-aligned (termed “out of phase”), the sum is zero and nothing is heard. This same process of summing sounds from different sources governs all sounds, from a quiet library, to a noisy highway, to the most beautiful symphony.

Wavelength, frequency, and pitch

The distance between peaks in a sound wave is called the “wavelength.” Shorter wavelengths correspond to higher frequencies and are heard as higher pitches. Smaller instruments usually produce higher frequencies and higher pitches.

waves

 





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