Chasmac is a semi-retired guitar teacher who has taught in various schools in London and elsewhere for over 30 years.
In Western music, especially in English-speaking countries, notes are named in order of ascending pitch after a repeating series of the first seven letters of the alphabet: A, B, C, D, E, F and G. In addition, there are five more pitches sandwiched between the notes A & B, C & D, F & G and G & A.
Those in-between notes are named in relation to the notes that they're sandwiched between. For example, the note between A & B can be called A sharp (A♯) as it's higher than A, or it can be called B flat (B♭) as it's lower than B. Similarly, the note between C and D is C sharp (C♯) or D flat (D♭), The same applies to the other pairs, too, apart from between the notes B and C and between E and F, which have no sharp/flat note between them. This brings the total to 12 note names. Obviously, there are a lot more than 12 notes at our disposal, so the letters just repeat indefinitely as we continue to ascend in pitch.
This is most easily seen on a piano keyboard, where the notes of the white piano keys are laid out as: ABCDEFGABCDEFGABC etc.,—until we run out of piano keys. The black piano keys can be named as sharp versions of the lower neighbouring note or as flat versions of the higher neighbouring note.
Every piano key is named the same as the piano key eight letters lower (or higher), and we say that the relationship (or interval) between the two similarly named notes is one or more octaves (from octo meaning eight).
The sharp/flat notes' pitches of the black piano keys are exactly half-way between the pitches of their nearest 'white note' neighbours on either side. They were first introduced into choral music gradually over the centuries as modifications of the so-called natural pitches: A, B, C, D, E, F & G. Now they're all of equal status, and in Western music, we now have 12 equally spaced (in pitch) notes within one octave rather than just the original eight 'natural' notes we inherited from Ancient Greece. The pitch difference between each successive note of the 12 notes is called a semitone (or half step). Two semitones make a whole tone (whole step).
The notes B-C and E-F don't have intervening sharp/flat notes as they're already just a semitone apart. All the other natural notes are two semitones or a whole tone apart. You can see on the piano diagram above or in the so-called musical alphabet below that there's no note between B and C and between E and F. That's because those two note pairs are only a semitone apart in pitch.
Naming Notes in Context
If there's no musical context, then it doesn't matter whether we choose to call the notes between the natural notes by their sharp name or their flat name. For example, the note between A and B can be called A sharp or B flat.
If, on the other hand, there is a key-based musical context, which is the case in almost all Western music, we need to use the correct note names that the standard Western music notation system requires in that particular context.
Note Naming in Key-Based Music
If a piece of music is in a major or minor key, it has an associated eight-note scale. When naming the notes of a major or minor scale, every letter must be used in succession starting from the key note.
Major Key Music
Music in a major key will be based on the notes of that key's major scale (at any octave). It may have some notes that are foreign to the key, too, but for the most part, it will be based on the scale notes. The notes of any major scale can be found by following the major scale's formula of tones (T) and semitones (S). In the US, the terms whole step (W) and half step (H) are often used. The table below shows the notes of the C major scale according to the major scale's formula, TTSTTTS or WWHWWWH if you prefer the American system.
Likewise, music in the key of G major will be based on the notes of the G major scale, derived from exactly the same arrangement of tones and semitones:
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Look at the second last note. It's F sharp (F♯). It must be called F sharp and not G flat because every letter must be used in succession. It's the 7th scale note, which must be named seven letters higher, so it must be called F♯, not G♭.
Minor Key Music
When dealing with music in a minor key, you can find the note names by following the natural minor scale's order of tones and semitones. Here are some examples of natural minor scales:
If you're playing or writing in a key and find a note that doesn't belong to the key's scale, then it's a chromatic note. For example, let's say you're writing a song in the key of C major and you have the note F followed by G. You decide you want a note in between. Should you call it F♯ or G♭? The scale of C major doesn't help as it has neither of those notes.
If it's a passing note between two notes a whole tone apart, or a chromatic auxiliary note, which goes up or down a semitone and returns to the same note, the general rule for naming them is that if they are rising a semitone, the note should be called 'sharp' (F sharp in this example) but if falling, it should be called 'G flat'.
- Key of C major (CDEFGABC)
- F - F♯ - G (Rising)
- G - G♭ - F (Falling}
- F - G♭ - F (Falling)
- G - F♯ - G (Rising)
If you come across a note that is foreign to the scale, and isn't a passing note, it may be a chord tone if one is being played at that time. It should be named according to the notes of the chord.
For example, if the key is C major, and you have the chord E major, which is foreign to the key, the correct name for any G♯/Ab notes appearing at that time is G♯ because E major's chord tones are the 1st, 3rd and 5th notes of the scale of E Major, which are: E, G♯ and B.
However, if the chord is F minor, which is also foreign to the key, any G♯/Ab notes should be called A flat because, the chord tones of F minor are F, Ab and C, or the 1st, 3rd & 5th notes of the natural scale of F minor.
B sharp, E Sharp, F Flat and C Flat
In music theory, any natural note can be made sharp or flat, and there are contexts in actual music or scales where you can see notes being called B sharp, E sharp, C flat and F flat. Of course, these are just special naming conventions derived from historical contexts; B sharp and E sharp now sound the same as the notes C and F, respectively, while C flat and F flat sound the same as B and E, respectively. However, they're named as sharps or flats to show their relationship to the key of the music.
For example, if the C major scale is C D E F G A B C, then the C sharp major scale must be C♯ D♯ E♯ F♯ G♯ A♯ B♯ C♯.
Double Flats and Sharps
If you chromatically flat a note that is already flat, it becomes a double flat note. If you sharp a note that is already sharp, it becomes a double-sharp note.
For example, the chord C diminished 7th consists of the notes C, Eb, Gb and Bbb (B double flat). That's because that note needs to be a diminished 7th interval from the root C. Bbb sounds exactly the same as A, but it can't be called A as A is the 6th scale note.
Double sharps can be found in contexts such as the scale of G♯ harmonic minor, which consists of the notes:
G♯ A♯ B C♯ D♯ E F♯♯ G♯
It has a double sharp because the G♯ natural minor scale already has F♯ and the harmonic minor always chromatically raises the 7th scale note by one semitone.
© 2011 Chas Mac