The A above middle C normally has a frequency of 440 cycles per second, or Hertz. This means that it vibrates 440 times per second. An A, one octave higher has a frequency of 880 Hz., exactly twice as many vibrations per second. The mathematical expression of this relation is 880:440 or 2:1. The following table shows the mathematical relationship of several intervals, ordered from consonant to dissonant.

Relation Interval
2:1 Octave
3:2 Fifth
4:3 Fourth
5:4 Major Third
6:5 Minor Third
9:8 Major Second
16:15 Minor Second

See Intervals in the Tutorial section.


Search   •    Write to us

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
José Rodríguez Alvira.