Form

Divide music into parts and convential muscial theory gives alphabet labels to the miscial parts within a composition.

1-part form: A
e.g. Happy Birthday - is the most primitive song structure sometimes refered as the air or ballad form. The melody is repeated with slight variation.

2-part form: AB
Binary form contain 2 contrasting sections functioning as statement and counterstatement. e.g. Greensleeves in AABB

Song form: ABA
3-part or tertiary form. One of the simpliest way to write in song form is to vary and repeat the melody e.g. Twinkle twinkle little star. Another variation of song form is AABA with B bridging the stretched A.

Arch form: ABCBA

Classical form
- sonata - common in period from mid 1700 to early 20 century. Sonata are based on song form (ABA). The first part is the exposition which presents the main theme of the song as well as 2 or 3 minor themes. The second part (or B part) is called development often sounds belonging to another musical piece, usually in different ey and even different time Signature. The 3rdpart is to return to the theme and called recapitulation.

Sonata has its roots in language - in this case, the sonnet. In sonnet (like those Shakespeare wrote), the first quatrain (4-line verse) consists of 2 set of rhyming pairs (A part), whereas the second verse consists of 2 comptelely dofferent set of rhyming pairs (B part). The 3rd verse retruns to the rhyming A section.

- rondo (ABACA) or ABACADA. The A seciton is called refrain ties the pieces together. B, C and D are called episodes can be in any key or time signature. Rondo also has its roots in poetry. In 13th century France, the rondeau was a popular form of street poetry which often set to music

- Concerto - contrasts between having a large ensemble playing a section of music and a solo/smaller group playing the same or similar section.

- Symphony - performed by an orchestra. It combines several different muscial forms into one piece of music harmoniously. There are traditionally 4 movements in a symphony
(a) Sonata Allegro
(b) Slower movement
(c) Minuet or scherzo
(d) combination of sonata and rondo, a thematic repeat of the first movement.

- Fugue - first form that fully utiliuze the left hand of the pianist. The treble clef and the bass lef take turns carrying the melody.

- Divertimento - a light and short form of instrumental chamber music has several short movement chiefly for entertainment value.

- Minimalism - extremem simplication of rhythms, patten and harmonies. Prolonged chordal or melodic repetitions and often in trancelike effect - AAAA....

- Through composed - no repetitious of themes

Popular forms
- blues - AABA patternof I, IV and V

- rock - 32 bar compounded blue. One plays the first 32 bars, go to the second bridge and repeat the first 32 bars again e.g. every breath you take

- verse-chorus form: Intro ABAVBCB
Intro us usually instrumental and set the mood, or short spoken piece
A (verse) being the story of the song
B (chorus) is the hook of the osng, both lyrically and musically, should be the most memorable, anthemic part of the song. Often the title too
A (verse) is the part 2 of the story
B (chorus) reinforce the hook to make it memorable
C (bridge) can be instrumental or lyrical and is differnt sounding than the verse or chorus
B (end, chorus) repeat chorus to fade or just stop at the I chord (candence) after one time through

Cadences

Music has commas, full stops and paragraph used in the same way as storytelling.  The term for phrase (sentence) ending is called cadence.

Cadence means return to the I/i chord from iv or V chord. The stopping position of music that does not make sense to listener will not be fulfilling. Audiences expect a certain closure.

Authentic (Perfect) Cadences - V/v to I/i

Plagal Cadences IV/iv to I/i. It is used to end a phase rather than the song because they do not sound decisive as Authentic Cadences.  

Deceptive or interrupted cadences is to resolve the V/v to any chord other than I/i. The most common ones are V/v to VI/vi. This is one of the weakest cadence as it makes one feels incomplete.  Other forms are V to  IV/ii/V/VIIl.

Half (Imperfect) Cadences stop at IV, iv, V or v and not resolved to I (thus half of the cadence).

Chord Progression

Certain sequences of chords sound nicer than the others. Over time, a consensus devleoped to become the rules of chord progression.  The rules arre based on a concept called chord leading - certain chords naturally lead to other chords.

Major chord leading
I can appear anywhere in a progression (any chord can go to I)
ii to I, IV, V, or viio (minor seventh dim)
iii to I, ii, IV or vi
IV to I, ii, iii, V or viio
V to I or vi
vi to I, ii, iii IV or V
viio to I or iii

Minor chord leading
i can appear anywhere in a progression
iio or ii to i, iii, V, v, viio, VII
III or III+ to i, iv,IV, VI, #vio, viio, VI
iv or IV to i, V, v, viio or VII
V or v to i, VI or #vio
VI or #vio to i, III, III+ iv, IV, V, v, viio or VII
viio or VII to i

Common chord progressions
(1) I, IV, V and V7 (C, F, G, G7)
e.g. I-IV, I-V, I-IV-V or V7, I-IV-I-V of V7, I-IV-V-IV

(2) mixing other chords with combination of IV and V
e.g. I-ii-IV-V, I-ii-IV, I-V-vi-IV, I-vi-ii-V or V7, I-vi-IV-V, I-vi-ii-V7-ii

(3) starting with non-tonic chord
e.g. ii7-V7-I, IV-I-IV-V

(4) 12-baror blues progression
I-IV-I-V7-IV-I (C, F, C, G7, F, C)

(5) circles of fifths - each chord is a diatonic fifth above the following chords which makes each chord functionally a dominant for the next
I-IV-viio-iii-vi-ii-V-I (C, F, Bdim, Em,Am, Dm, G, C)

Chord Composition

A major triad is built of 2 intervals - a major third and a further minor third on top it.  Another way to look at this is a major third and a perfect fifth

A minor triad composed of a minor third and a further major third on the top.  In other words, a minor third and a perfect fifth

An augmented triad composed of a major third plus a major third, or in other words, a major third and an augmented fifth.

A diminished triad composed of a minor third and another minor third on top, or in other words a minor third and a diminished fifth.


C- Major chords are happy, simple, honest and bold composed of 1,3,5
Cm - Minor chords are sad and serious composed of 1,3b,5
Cmaj7 - Major seventh are pretty, delicate, sensitive and thoughtful composed of major+7
Cm7 - Minor seventh are pensive, moddy and introspective composed of minor+7b
C7 - Dominant 7 are sassy, outgoing and strong composed of major+7b
C6 - Major sixth are playful composed of major+6
Cm6 - Minor sixth are dark, sensuous, troubled composed of minor+6
Csus4 - Suspended 4 are regal and material composed of C without third (sus part)+4 (i.e. 1,4,5).  This chord creates a harmonic suspension and could be resolved by returning to the original triad
C9 - Ninth are energetic and lively composed of major+9 (or 2 raised to an octave)
Cm9 - Minor ninth are sad, tender and complex composed of minor+9
Cdim - Diminished are dark, strained and complex composed on a Minor with its fifth flatted (i.e. 1,3b,5b)
C+ - Augmented are anticipatory and full of movement composed on Major with its fifth sharped
Cm7/b5 - Minor 7, flat 5 or half diminished are disparaging, sorrowful, difficult and deep composed of Cm7 with 5b

In summary,
Cmaj7 = C + 7
C7 = C + 7b
C6 = C + 6
C9 = C + 9 = C + 2
C+ = C with 5#

Cm = C with 3b
Cm7 = Cm + 7b
Cm6 = Cm + 6
Cm9 = Cm + 9
Cdim = Cm with 5b

Csus4 = C - 3 + 4