MIDI notes numbers and Middle C

Middle C is MIDI Note Number 60.

This can be C3 or C4, or even C2 or C5. There is no defined standard or convention. The MIDI standard only says that the note number 60 is a C, it does not say of which octave.

Ref.: Complete MIDI 1.0 Detailed Specification :

Each note is assigned a numeric value, which is transmitted with any Note-On/Off message. Middle C has a reference value of 60. This is the middle C of an 88 note piano-style keyboard though it need not be physically located in the center of a keyboard.

Other refs:

• Notes on a piano: https://en.wikipedia.org/wiki/Piano_key_frequencies
• What wikipedia says: https://en.wikipedia.org/wiki/C_(musical_note)#Middle_C

Octaves range depending on the definition of middle C:

With middle C defined as C3 :

With middle C defined as C4 :

All note numbers alongside key numbers of 61 and 88 notes piano keyboards:

With middle C defined as C4

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