Diatonic and chromatic half steps
The half step (UK: semitone) is the smallest distance between two notes in Western music. But not every half step is written the same way, which gives two categories you must tell apart when you analyze a score:
- Diatonic half step: two notes with different, consecutive letter names. It can happen between natural notes (E–F, B–C) or with accidentals (C–D♭, F♯–G). On the staff it always moves from a line to the adjacent space, or the other way around.
- Chromatic half step: two notes with the same letter name and different accidentals (C–C♯, G♭–G). On the staff both notes sit on the same line or space. Note that the accidentals must differ by exactly one step: C♭ to C♯, for example, is two half steps.
Unison and enharmonic notes
When the distance between two sounds is minimal or zero, two concepts are easily confused:
- Unison: two notes with exactly the same name and the same sound (for example, two violins playing the same middle C). The distance is zero half steps.
- Enharmonic notes: notes with different names that stand for the same sound on a piano or on the frets of a guitar. For example, C♯ and D♭, or E♯ and F, sound the same but are written differently for harmonic reasons. On the staff they appear at different heights.
Reference table: half steps and zero distances
| Concept | Note names | Resulting sound | Examples |
|---|---|---|---|
| Diatonic half step | Different and consecutive | 1 half step apart | E–F, G♯–A |
| Chromatic half step | Same letter name | 1 half step apart | C–C♯, D–D♭ |
| Unison | Same | Same sound (0 half steps) | D–D, F–F |
| Enharmonic notes | Different | Same sound (0 half steps) | F♯–G♭, B♯–C |
Tips for spotting them visually
When you do the exercises, do not try to hear the difference at first. Rely on how the notes look on the staff:
- Are the notes in the same place on the staff? If they have different accidentals, it is a chromatic half step. If they have no accidentals, or the same one, it is a unison.
- Are the notes in different, adjacent places (line to space)? Then it can be a diatonic half step, or even enharmonic notes if their accidentals cancel the visual distance (such as E♯ and F).
Build half steps and enharmonic notes
A note appears on the staff. Following the instruction, write the matching note: the diatonic half step, the chromatic half step, the enharmonic note or the unison.
More practice
To train your ear as well, use the reference tones of the online tuner and compare the sound of each interval with a pure tone. The online metronome helps you build sight-reading speed.
Frequently Asked Questions
What is the difference between a diatonic and a chromatic half step?
A diatonic half step joins two notes with different letter names and covers two neighboring staff positions (E–F, B–C). A chromatic half step joins two notes with the same letter name and different accidentals, so it stays on the same position (C–C♯, F–F♯). Both are the smallest distance in the Western tonal system.
Where do enharmonic notes and unisons appear in practice?
Enharmonic notes are notes that sound the same (same pitch in equal temperament) but are written differently. For example C♯ and D♭, F♯ and G♭, B and C♭. On fixed-pitch instruments (piano, guitar) they are identical; on instruments with flexible intonation (strings, winds) there can be a slight difference.
What is a unison in music?
The unison is the interval of number 1: two notes with the same letter name in the same octave. A perfect unison is two C's or two A's that are exactly the same. An augmented unison would be, for example, C and C♯ (same line or space, different accidentals), a chromatic half step apart.
How are half steps written on the staff?
A diatonic half step appears between neighboring positions of the staff (E and F, B and C). A chromatic half step appears at the same position with a different accidental: for example, A and A♯ on the same line or space, told apart only by the sharp.
What are enharmonic notes useful for?
Enharmonics let you write the same sound with the most readable spelling for the key. For example, in D♭ major you write G♭ even though it sounds like F♯, because G♭ fits that key better. They also make enharmonic modulation possible: changing key by using the identical sound.