Enharmonic equivalents describe notes, intervals, key signatures or chords that share the same pitches, but have different names depending on the musical context.
For example, the black note on a keyboard just to the right of C natural can be written as C sharp or D flat:
The note sounds the same, but can be named differently. So, C sharp and D flat would be described as an enharmonic equivalent.
Enharmonic Equivalent Notes
An Enharmonic Equivalent note is one which has more than one pitch name (as in the example above).
The obvious notes are the black notes on a keyboard which can be described as either sharps or flats depending on the context:
However, the white notes on the keyboard also have enharmonic equivalents as well. For example – E natural can also be written as F flat, F natural can be written as E sharp, B natural can be C flat and C can be B sharp:
This can be extended further if double sharps and double flats are used!
For example, D natural could be named C double sharp or E double flat! G natural could be F double sharp or A double flat and A natural could be B double flat or G double sharp:
So why on earth do we have this crazy complexity?!?
2 main reasons –
- To accurately show the musical context of a note
- To make it as easy as possible for a performer to read the music.
Firstly, the naming of the pitch of a note depends on the musical context.
For example, if I am writing a piece of music in G minor the key signature is 2 flats (B flat and E flat). If I want to use the G harmonic minor scale then I will raise the 7th note of the scale by a semitone/half step from F to F sharp.
The note sounds the same pitch as a G flat, but it would be inaccurate for me to write G flat as I have raised the seventh note (F) to a sharp, not lowered the tonic (G) to a flat.
This means that the sheet music I am writing accurately expresses my composing intentions:
However, if I am writing a piece of music in D flat major (5 flats – B, E, A, D, G) then I may well be writing G flats in my melody:
The G flats sound the same as an F sharp, but it would be inaccurate and misleading for me to write the notes as F sharps in this musical context because the piece is composed in D flat major.
Composers also use enharmonic equivalents to make a passage of music easier to read.
For example, in this extract written in B flat minor, C flats are substituted for B naturals as less accidentals are needed and so the passage is much easier to read:
Here is an example of an enharmonic equivalent from the 2nd movement of Beethoven’s Sonata in E minor.
You can see how in the 4th bar of the extract Beethoven changes the E flat to a D sharp because he is modulating keys from C minor through C sharp minor before landing in C sharp major in the final bar:
Enharmonic intervals are “intervals that differ from each other in name, but not in any other way”. (Oxford Dictionary of Music, Kennedy, M. 1985).
For example, the interval from C to G sharp is an augmented 5th, but from C to A flat (same sounding pitches) is a minor 6th.
Enharmonic Equivalents – Key Signatures
There are 6 common key signatures/scales that can either be written as flats or sharps.
For example, if I play a scale of C sharp major and D flat major I am playing the same note pitches. The scale, fingering, etc.. remains the same and the sounding pitches are exactly the same as well:
These 6 enharmonic pairs as they are called are as follows (3 major and 3 minor scales):
B major/C flat major,
F sharp major/G flat major,
C sharp major/D flat major,
G sharp minor/A flat minor,
D sharp minor/E flat minor,
A sharp minor/B flat minor.
In each of these enharmonic pairs the number of sharps and flats always adds up to 12 – (for example, C sharp major has 7 sharps and D flat major has 5 flats – 7+5=12).
So, when a composer is wanting to write in one of these keys they have a choice as to what key to write it in.
For example, J.S. Bach wrote preludes and fugues in all of the keys. Theoretically, he could have chosen to write his prelude in F sharp major in G flat major!
Enharmonic Equivalents – Chords
The choice of which key signature to use obviously has a direct impact upon which chords are played in a piece/song.
For example, the primary chords in D flat major are D flat, G flat and A flat.
In C sharp major, the primary chords contain the same pitches, but are written C sharp, F sharp and G sharp:
Enharmonic Equivalent Chart
I have put together an enharmonic equivalent chart for you to download and print off for free so that you can have an easy reference guide to help you. Click on the link below to download the chart: