Magic Music Clacton — musical sound explained | magicmusicclacton.com
Pitch is the perceived height of a note; frequency is the vibration rate behind it, measured in hertz. This page sets out how the two relate and why octaves always double.
Every musical note begins as a vibration: a string swinging, a reed flexing, a column of air pulsing. When the vibration repeats regularly, the number of cycles per second is the frequency, expressed in hertz (Hz). A string vibrating 440 times per second produces the note A above middle C — the modern reference pitch for orchestras.
Pitch is the perceptual shadow of frequency. Listeners agree on which of two tones is higher because the ear's response tracks frequency almost one-to-one across the musical range. But pitch belongs to the listener: at high loudness or with complex tones, perception can bend slightly away from the raw number, which is why acoustics treats pitch as psychoacoustic.
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The most important relationship is the octave. Doubling any frequency raises the pitch by one octave; halving it lowers by one. The note A exists at 55, 110, 220, 440, 880 Hz and beyond — the same letter name at every doubling, which is why octaves share names in virtually all musical traditions.
Within the octave, equal temperament spaces twelve semitones evenly on a logarithmic scale: each step multiplies frequency by the twelfth root of two, about 1.0595. Middle C (C4) sits near 261.63 Hz on this system; the C above it, at 523.25 Hz, is exactly double.
The usable range of musical pitch is narrower than hearing itself. Humans hear roughly 20 Hz to 20,000 Hz, but the standard piano spans 27.5 Hz to about 4186 Hz, and most melody lives between 100 Hz and 1000 Hz — the band where the ear judges pitch most precisely.
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