What does B5 and B4 mean?enter image description here

Is it referring to the bar number or the octave in which the note is present?

So is this B a B4? enter image description here

  • 2
    Letter names are really exactly what is said, letters for names. I have not seen any theory where you are expected to add the octave in your answer.
    – Neil Meyer
    Nov 25, 2016 at 9:39
  • But does it represent the octave
    – user34782
    Nov 25, 2016 at 9:54
  • Octave designation is actually VERY common in music theory.
    – Richard
    Nov 25, 2016 at 21:08
  • Yeah, poorly-written question on the assignment IMO. Anyone asks me "what letter name was that", my response is 'B' - the letter's name! Octaves are important, but if they wanted the scientific pitch designation they should have said so.
    – user45266
    Oct 20, 2020 at 20:05

2 Answers 2


It is called scientific pitch notation. From wikipedia we have:

Scientific pitch notation (or SPN, also known as American Standard Pitch Notation (ASPN) and International Pitch Notation (IPN))1 is a method of specifying musical pitch by combining a musical note name (with accidental if needed) and a number identifying the pitch's octave.

So the number is the octave. Middle C is in octave 4.


4 and 5 represent the octave! Letter B means it's a B note. enter image description here

The same way you say play the sequence C2-G2-C3-C2-G2-Bb2-Eb2-F2-G2 in a 4/4.

  • Does B4 mean middle B/the B after middle C?
    – user34782
    Nov 25, 2016 at 10:28
  • Middle C is mostly C4 (though sometimes C3) and B4 is a C5 flat. Nov 25, 2016 at 10:30

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