Perfect 4th
5 semitones — open and neutral, the inversion of the 5th
Degree 4Solfège: faNotation: P4
The perfect 4th is an interval of 5 semitones — the inversion of the perfect 5th. It is consonant — open, neutral, slightly suspended. It appears in the minor pentatonic and every major mode except lydian, and is derived from the 4th harmonic (4:3).