Musical Intervals
An interval is the distance in pitch between two notes.
Sharps and flats
- A sharp (♯) raises a note by one semitone.
- A flat (♭) lowers a note by one semitone.
- A natural (♮) cancels a sharp or flat.
Some notes share the same pitch. These are called enharmonic (for example, C♯ and D♭).
Steps
- A half step is the smallest distance between notes.
- A whole step is two half steps.
Scale degrees
Notes in a scale are numbered from 1 to 8:
- Tonic
- Supertonic
- Mediant
- Subdominant
- Dominant
- Submediant
- Leading tone
- Tonic (octave)
Interval names
Intervals are named by counting scale degrees.
For example:
- C to D = a second
- C to E = a third
- C to F = a fourth
Major, minor, and perfect intervals
- Seconds, thirds, sixths, and sevenths can be major or minor.
- Fourths, fifths, and octaves are perfect intervals.
Augmented and diminished
- Raising a perfect or major interval by a semitone makes it augmented.
- Lowering a perfect or minor interval by a semitone makes it diminished.
Compound intervals
Any interval larger than an octave is a compound interval (for example, a ninth = an octave plus a second).
Source
- The Complete Idiot's Guide To Music Theory by Michael Miller