Tuning

Frequencies for equal-tempered scale, A4 = 440 Hz

(Middle C equals C₄ )

Frequency is a measure of vibration or oscillation, related to how quickly an object or a signal moves backwards and forwards between two positions. Sound is itself another type of vibration, caused as air molecules vibrate and collide, and pass on energy. So vibrating objects – such as musical instruments – cause sound vibrations that our ears can easily interpret. The measurement unit for vibration frequency is known as Hertz or Hz. So, if a drum is tuned to 100 Hz, its drumhead will vibrate up and down 100 times in a single second, similar applies to guitar strings and glockenspiel bars. Conveniently, some frequencies and frequency relationships are much more ‘musical’ than others, which provides a basis for music as we know it, and the tuning of musical instruments.