Interval Quality

Chromaticism in music means that more descriptive intervals names are necessary

Families

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The Interval of a SECOND

• Belongs to the imperfect family
• Inverts to sevenths

	Augmented second (A2) = 3 semitones
	Major second (M2) = 2 semitones
	Minor second (m2) = 1 semitone
	Diminished second (d2) = 0 semitones

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The Interval of a THIRD

• Belongs to the imperfect family
• Inverts to sixths

	Augmented third (A3) = 5 semitones
	Major third (M3) = 4 semitones
	Minor third (m3) = 3 semitones
	Diminished third (d3) = 2 semitones

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The Interval of a FOURTH

• Belongs to the perfect family
• Inverts to fifths

	Augmented fourth (A4) = 6 semitones
	Perfect fourth (P4) = 5 semitones
	Diminished fourth (d4) = 4 semitones

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The Interval of a FIFTH

• Belongs to the perfect family
• Inverts to fourths

	Augmented fifth (A5) = 8 semitones
	Perfect fifth (P5) = 7 semitones
	Diminished fifth (d5) = 6 semitones

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The Interval of a SIXTH

• Belongs to the imperfect family
• Inverts to thirds

	Augmented sixth (A6) = 10 semitones
	Major sixth (M6) = 9 semitones
	Minor sixth (m6) = 8 semitones
	Diminished sixth (d6) = 7 semitones

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The Interval of a SEVENTH

• Belongs to the imperfect family
• Inverts to seconds

	Augmented seventh (A7) = 12 semitones
	Major seventh (M7) = 11 semitones
	Minor seventh (m7) = 10 semitones
	Diminished seventh (d7) = 9 semitones

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Unisons and Octaves

• Belong to the perfect family
• Invert to one another (unisons to octaves, octaves to unisons)

Augmented unison (A1) = 1 semitone	Augmented octave (A8) = 13 semitones
Perfect unison (P1) = 0 semitones	Perfect octave (P8) = 12 semitones
Diminished unison (d1) = -1 semitone	Diminished octave (d8) = 11 semitones

Octave – frequency x2; same letter name (where the NMA repeats)