Scientific pitch notation (SPN), also known as American standard pitch notation (ASPN) and international pitch notation (IPN), is a method of specifying musical pitch. It combines a musical note name (with an accidental if needed) and a number identifying the pitch's octave. The purpose of SPN is to provide a standardized way of representing pitch that is independent of specific tuning systems or instruments. In SPN, the octave numbering starts with the lowest audible pitch range, which is typic