What is music?
Music always involves combinations of pitch, timbre, rhythm, loudness, tempo, melody and harmony.
The different elements of music can be combined to create a huge diversity of music - from African drumming to Johann Sebastian Bach, Inuit throat singing to Razorlight.
Pitch is a building block for music in all known cultures. Pitch (measured in cycles per second or hertz) is linked to the acoustic structure of the sound wave, especially the regularity or rate of repetition. For simple tones like that from a tuning fork the repetition rate and pitch have the same value as the single frequency within that sound. For each doubling of wavelength, pitch goes up an octave.
Most musical instruments and people's voices contain a large number of frequencies at the fundamental frequency - the note we hear - and higher harmonics (notes at multiples of the fundamental frequency).
The fundamental frequency can be removed and listeners still hear the same note - the 'missing fundamental' phenomenon. Pitch therefore does not depend just on the brain measuring some aspect of the stimulus: it is a perception that requires the brain to 'abstract' sound features.
Timbre is the difference in sound quality between, say, trumpets and violas playing the same note. It is important in musical traditions where multiple instruments are used and can be used like a palette of 'colours' to add interest to composition.
Examples of the missing fundamental, timbre and pitch can be heard in the online audio library.
