1. Intervals
Week 1.7

2. Vocabulary

3. Interval: Musical Space Between two notes
Named according to size and quality
To count the size:
Count the bottom note as 1, then count forward in the alphabet to next pitch
Example: D-A is a fifth
The size between two notes stays the same, regardless of the accidental in front of them
Ex: Any kind of C to any kind of A is a 6th
**unison: the interval that occurs when two notes are on the exact same pitch and there is no space between them
Melodic Intervals: Occur when notes sound one right after the other (like in a melody)
Harmonic Intervals: Occur when notes sound at the same time (creating harmonies)
**Melodic and Harmonic intervals are counted the same way

4. Thirds: Line to next line OR space to next space
Fifths: line, skip line, next line OR space, skip space, next space
Sevenths: line, skip two lines, next line OR space, skip two spaces, next space
Seconds, fourths, sixths, octaves: one pitch on a line and one pitch on a space

6. Compound Intervals
Compound Interval: Interval larger than an octave
Ex: m63, A4-B5=ninth
Simple Interval: interval up to an octave
To count compound interval, add 7 to the interval size:
EX: m 63, A-B is a 2nd, plus 7 is a 9th

8. Interval Quality
The number distance between two notes gives the size, but all intervals also have a quality (major, minor, perfect, augmented, or diminished)
Quality is determined by the number of half steps between the two notes:
Minor Second (m2): One half step
Major Second (M2): two half steps
Minor Third (m3): three half steps
Major Third (M3): four half steps
Perfect Fourth (P4): five half steps
Augmented Fourth/Diminished Fifth (A4/D5): six half steps
Perfect Fifth (P5): seven half steps
Minor Sixth (m6): eight half steps
Major Sixth (M6): nine half steps
Minor Seventh (m7): ten half steps
Major Seventh (M7): eleven half steps
Perfect Octave (P8): twelve half steps

9. To determine the quality, follow the INTERVAL FLOW CHART!!! 

11. Inverting Intervals
Two intervals that are made up of the same pitches but in reverse order are inversely related.
Knowing the inversions of an interval can help in identifying and spelling.
When inverting:
Perfect intervals remain perfect
Major intervals invert to minor intervals (and vice versa)
Augmented intervals invert to diminished intervals (and vice versa)
The two inversion sizes add up to 9 (ex: the inversion of a 2nd is a 7th)

16. Enharmonically Equivalent Intervals
Intervals that span the same number of semitone but have different names are enharmonically equivalent.
Ex: m3 and A2.
It is imperative to spell the interval correctly, as that determines how it functions within a tonal context
Consonat and Disonant Intervals
Consonant: Pleasing to the ear, stable (Historically: unisons, octaves, fifths, thirds, sixths)
Unisons, Octaves, fifths considered perfect consonants
Thirds, sixths considered imperfect consonances
Dissonant: jarring, clashing, unstable (Historically: seconds, sevenths, any augmented/diminished intervals)
**The Perfect fourth has been grouped as both

17. Interval Class
Intervals can also be grouped by Interval Class