So far in this series of posts on the basics of sound we have talked about sound and how it travels through the air and also frequency and wavelength. In part 3 we are going to talk about pitch and how it relates to frequency.

The Difference Between Them
Pitch and frequency are very similar and sometimes I hear people get very confused between the two. The main way of remembering the difference is to understand that frequency is the scientific way of specifying a sounds wavelength in hertz (the number of wavelengths per second) where as pitch is the musicians way of referring to a fundamental frequency (the main frequency of a sound) through the use of letters and symbols.

Standardized Pitch
Pitch can be set at any frequency we want, I could set for example the A above middle C to be 500Hz and as long as everyone else playing other instruments along with the music had also set their tuning to correspond to mine, it would make no difference apart from we would be slightly higher in frequency. But to try and keep some standardization in the instrument market we have what’s called standardized pitch (set by the International Organization for Standardization (ISO). In standardized pitch the A above middle C is set to the frequency of 440Hz (A440).

Octaves
From this A of 440Hz (A440) all the other notes around it can be tuned from this single note. Octaves will come across the same note A again, and these octaves of As work out that every octave higher is double the frequency of the previous octave. So the A one octave above the note of A440 will have a frequency of 880Hz (A880). The A one octave below A440 will have a frequency of 220Hz (A220). Even though the gap between our different octaves of As is different in the amount of frequency, we still perceive the distance between them to be the same.

The Other Notes in the Chromatic Scale
The twelve note tuning on most modern western instruments is called the Chromatic Scale which is C C# D D# E F F# G G# A A# B and back to C to start again. These notes can all be worked out in frequency from our octaves of As. Every pitch higher above the previous pitch is our previous frequency times the twelfth root of two which equates to 1.0594630 (number keeps going). So basically our A# above the A of 440Hz is going to be 440 X the twelfth root of two (1.594630 etc.) which is 466.16Hz.

Hopefully from this quick guide you can see how pitch corresponds to frequency and how they are two different methods of showing the wavelength of a sound.

Article written by Edward Cufaude for Rhythm Creation