Transcript AP Theory Part 2 Voice Leading

AP Music Theory
Voice Leading
Chapter 5 – The Melodic Line
 Rhythm should be simple
 Notes in the melody should belong to the
chord harmonizing it
 Melody should be conjunct (stepwise motion)
 Shape of the melody should be clear but
simple with a single focal point or highest note
to the melody
 Leaps:
 Avoid augmented intervals, 7ths and intervals larger than an
octave
 Diminished intervals used if melody changes direction by
step immediately after the interval
 Melodic interval larger than a Perfect 4th is both approached
and left in the opposite direction
 Smaller leaps used consecutively in the same direction
should outline a triad
 Tendency tones
 7th degree of the scale moves up to the 1st degree unless
they are descending in a scale 1-7-6-5
 The 4th scale degree often moved down to the 3rd scale
degree
 Notating Chords
 Stems in soprano and tenor voice always go
up
 Stems in the alto and bass voice always go
down
 The alto voice stays within the confines of the
treble clef in a reduced score
 The tenor voice always stays within the
confines of the bass clef in a reduced score
 Voicing a single triad
 Close structure – lass than an octave between soprano and
tenor voice
 Open structure – more than an octave between the soprano and
bass voice
 Example 5-5 – illustrates spacing in hymn style
 Do not allow any part to cross above the soprano or below the
bass
 Alto and tenor parts can cross briefly if there is a musical reason
but generally not done at this level. Example 5-7
 Spacing should remain within an octave for adjacent parts
excluding the bass
 Can be more than an octave between the tenor and bass voice
 Voice Movement
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Static is unmoving repeating the same notes
Oblique is one voice moving and the other remaining still
Similar – both voices moving in the same unequal direction
Contrary – both voices moving in the opposite direction
Parallel – both voices moving in the same direction equally
Parallel 5ths and octaves are avoided completely!
Consecutive 5th and octaves are also avoided
Octaves by contrary motion are found at cadences and are ok
 Example 5-14
 Unequal 5ths – dim 5th to a Perfect 5th are unacceptable!
 Direct 5ths and Octaves – when soprano and bass parts move in
the same direction into a P5 or P8 with a leap in the soprano part
and are unacceptable Example 5-17 shows instrumental
music in which the 5th are hidden by accompanying figures
Chapter 6 – Root position Part
Writing
 Root Position writing with repeated roots
 4 part Texture
 All members of the triad are present
 The root is always doubled
 The leading tone (7th degree) is never doubled!
 3 part textures
 The 5th of the triad is often omitted
 The final I chord may have tripled root
 An incomplete triad will have the root doubled
 The leading tone(7th degree) is never doubled!
 Root position part writing with roots a 4th (5th)
apart.
 Four Part Textures Method ONE
 Keep the common tone of both chords in the same voice
 Upper parts move by step in the same direction
 Step Up if the if root movement is a P5 down
 Step Down if the root movement is a P5 up
 Four Part Textures Method TWO
 Move all three upper parts in the same direction with no leap
larger than a third
 Step UP if the root movement is a P5 down or P4 up
 Step DOWN if the root movement is a P5 up or a P4 down
 If the leading tone is in an inner voice (alto/tenor) it leaps down
to the 5th scale degree
 Four Part Textures Method THREE
 Useful for changing between close and open structures
 Keep the common tone of both chords in the same voice
 The voice that has the 3rd in the first chord must leap to the
3rd in the second chord
 Remaining voice moves by step
 Leading tone can leap up to the 3rd scale degree in the inner
voices (alto/tenor).
 Three Part Textures
 Remember that each chord must contain at least a root and a
3rd
 Watch out for spacing issues and parallel movement of 5ths
and Octaves.
 Aim for smooth voice leading instead of complete chords.
 Root Position Part Writing with Roots a 3rd
(6th apart)
 Four Part Textures
 The two upper voices that have tones in common
with the second chord remain stationary
 The remaining voice moves by step
 Step UP for roots that go down 3rd (I-vi)
 Step DOWN for roots that go up a 3rd (I – iii)
 Three Part Textures
 In root movement that goes UP do not omit the 5th
of the second chord
 Root Position Part Writing with Roots a 2nd (7th)
apart
 Four Part Textures
 These chords have no tones in common so every part must
move
 Doubled Root
 If bass moves up upper voices move down to the next chord
tone
 If bass moves down the upper voices move up to the next
chord tone
 Deceptive Progression (V-vi or V-VI) Example 6-10
 Leading tone moves parallel with the bass up to tonic
 Other two voices move down contrary to the bass to the next
chord tone
 IN Major keys if the leading tone is in the inner voices
(alto/tenor) it may move down by step to the 6th scale degree.
This does not work in minor keys. You must resolve up to tonic
creating a doubled 3rd.
 Three part textures
 Two scenarios
 Complete triad resolves to incomplete triad with a 3rd
and two roots
 Incomplete triad (2 roots and a 3rd) to a complete triad.
 Resolve the 7th scale degree up to tonic except when in
an inner voice in major keys where it can go down.
 Instrument Ranges and Transpositions
 See Appendix A in the back of your book
Chapter 7 – Harmonic Progression
 Sequence – a pattern that is repeated in the same
voice that begins on a different pitch class
 Tonal Sequence – will keep the pattern in a single key
 Real sequence (modulating sequence)– transposes the
pattern to a new key
 Modified Sequence – neither tonal or real
 A sequence can be melodic, harmonic or both
 The difference between a real sequence and real imitation
 Example 7-3
 One Common Sequence is the I-V-vi-iii-IV-I (Pachelbel’s
Canon)
 Circle of Fifth’s Progression
 Roots by descending 5ths and or ascending 4ths
 If continued long enough you could run into a tritone
 Example 7-6
 Often in connection with melodic sequences,
popular music and jazz
 This is the most basic progression in tonal
harmony
 Example 7-7
 The V-I progression
 I-V-I or I-V7-I is the most essential element of a tonal work.
 The ii chord – ii – V – I
 Extending backwards in the circle of fifths from the V chord
we have ii – V – I
 Many musical phrases contain a I-ii-V-I progression
 The vi chord vi – ii – V – I
 One more step backwards in the circle of fifths takes us to
the vi chord
 In root position this pattern produces an ostinato (repeated)
bass pattern heard in popular tunes
 The same progression in minor are almost always identical
to major keys
 The iii chord iii – vi – ii – V – I
 Another 5th backwards brings us to the iii chord which is far
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removed from the tonic triad
The actual iii chord is rarely used in major keys
If the 3rd degree is used as a bass in major keys it is almost
always associated with a I in first inversion, not a iii chord
It does occur occasionally and always followed by a vi chord
in major
It is used more frequently in minor keys
It can occasionally be used to harmonize a descending 1 – 7
– 6 soprano line.
 The vii chord
 Continuing back another 5th brings us to the vii
chord
 The vii – iii is sometimes used in sequences but
not common
 The vii chord acts as a substitute for the V chord
 If V and vii are next to each other, the V will follow
the vii because V is stronger
 The most common use of vii is in first inversion
between two positions of the tonic triad. I – vii6 – I6
or I6 – vii6 – I
 The vii6 is also useful in harmonizing a 6-7-1
soprano line
 I – IV – vii6 – I
 The IV chord
 The last chord in the progression is the IV chord
 It has three common functions
 IV proceeds to the I chord (a Plagal Cadence)
 More frequently IV is linked with the ii chord which can
substitute for the IV – V/vii Predominant function
 It can be followed by ii as in IV – ii – V
 Common Exceptions
 V – vi (the deceptive cadence)
 iii – IV
 Differences in Minor Keys
 The Subtonic Chord (VII – III ) which sounds like a
V – I (the VII sounding like a V and the III
sounding like a I in the relative major)
 The v6 – iv6 (the minor v chord does not have a
dominant function)
 Progressions Involving Seventh Chords
 Almost in every case seventh chords function
in the same way as triads
 The only exception is the tonic seventh chord
which in most cases is followed by a
subdominant (IV) chord.
 Harmonizing a Melody
 In root position triads , do not use diminished triads
 First select the chords for the beginning and the last
two or three chords
 2nd – write out the possibilities for each remaining
chord (remember that every melody note can serve
as the root, 3rd or 5th )
 Again avoid diminished chords (vii)
 3rd – compose the rest of the bass line to create a
good harmonic progression avoiding parallel or direct
5ths and Octaves
 4th – after finishing the bass line, fill in the two
remaining voices following the guidelines already
learned.