APMH Advanced Popular Music Harmony CMT2007
An Introduction to Guide Tones and Guide Tone Lines Guide Tones (and Guide Tone Lines) are very important concepts in jazz and popular music harmony. A guide tone is an important constituent of a chord, often it refers to either the 3rd or the 7th but we’ll call these ‘Essential Guide Tones’ (EGT) so we can broaden the category as detailed below. A Guide Tone Line is a simple melodic line (usually with one note per chord change) which fulfils 2 conditions 1) Each note ‘agrees’ with the chord of the moment, either by being a chord-tone or an ‘acceptable’ non-chord tone (also known as an ‘extension’) 2) A guide tone line is very smooth, movement from one note to the next is almost entirely within the range of a major 2nd in either direction (or static). Let’s divide the possible guide tones in a guide–tone line into 3 categories Essential Guide Tones. These provide the essential quality of the chord. It’s the 3rd and 7th of the chord (or 3rd and 6th for a major or minor 6th and the 3rd is replaced by a 4th on sus chords) Chord Tones These are chord tones and are always usable (with one caveat, the root in the melody of a major 7 chord can sometimes be problematic or unidiomatic due to the minor 9th interval) Acceptable Non-Chord Tones (NCT) or ‘Extensions’. These are non-chord tones which nonetheless work well with the harmony. It’s impossible to create rules which cover every context but there are some good general tips below. Extended Harmony: What’s Acceptable? Context is king and the short answer is “whatever sounds good” but under most conditions these guidelines will be useful:
1) Most notes from the key will work, with the following cautions. a. 4th on a chord from the major or dominant family can be problematic, because of the minor 2nd and disruption of function. b. A minor 6th on a minor or major chord can be dissonant c. Dominant chords (particularly when ‘functioning’) is extremely tolerant of extensions with the acceptance of mixing major and minor (or augmented) degrees of the same degree in particular a major 7th on a dominant chord is very rare 2) Non-diatonic non-chord tones can work well. 9ths and #11s for example are very common extensions to major and dominant chords in many contexts. 6ths (or 13ths) on major (or major 7) chords, 6ths, 9th and 11ths on minor and 11ths on minor7(bb) chords are very common in many situations. The bluesy #9 (minor 3rd) and #11(b5) against major and dominant chords (particular when the I (I7) or V (V7) is very common in many blues-influenced contexts. Extended Harmony: A Rough Guide The following table gives a guide to what extensions may be used on a given chord. Note that if the given chord is say E9, then that extension is a given (i.e. a 9th) and other versions of that extension (e.g. b9 are rare). The following is just a guide, context is everything and anything can be made to work, think of this as a personal assistant to your ear.
MAJOR FAMILY Major, 6th and Major 7th Chords b9
9 #9/b3 3 4 #4
5 b6 (or b13)
Very rare unless it’s in the implied key of the moment (e.g. and F on an E chord in the key of Am) or there’s a particular scalar context. E.g. a Db on a C chord in C Spanish Phrygian. Very common (although sometimes non-diatonic use is problematic) Very common if a ‘bluesy’ element is appropriate. However it’s most common on the I or V chord and rare on the IV Chord Tone (and essential guide tone) Quite rare unless in passing or there is an almost modal quality. In a standard context rare on the IV chord A common extension giving a floaty lydian quality. Very common on the IV chord (where it’s diatonic) and on borrowed chords. Using on I is usually the most surprising. Chord Tone Like b9, rare unless it’s in the implied key of the
6 (13) b7
7
Root/Octave
moment (e.g. C on and chord in the key of E in Am) or there’s a particular scalar context. Very common (and it’s a CT and EGT on a major 6th), some non-diatonic use may be problematic, but generally very usable Completely acceptable on major and major 6 chords when a bluesy vibe/dominant implication in appropriate. But prolonged use on a major 7 is highly dissonant and unusual. Essential guide tone on a Major 7. In a jazz idiom very common on a major 6. However it may be unidiomatic on a major chord, if there is prolonged use the harmony would probably be written as major 7 Chord tone and generally perfectly acceptable but prolonged use of octave on a major 7 melody can be inappropriate, and that’s why many jazz standards end on a major 6th chord rather than a major 7 chord as the melody often ends on the root.
MINOR FAMILY Minor, Minor 6th, Minor 7th Minor 7(b5), Minor (maj7) b9 9 b3 3 4/11 #4/b5
5 b6 (or b13) 6 (13) b7 7
Rare even when the b9 is diatonic (e.g. on the IIIm chord in a major key). Most common when there is a Phrygian modal implication. Very common (although sometimes non-diatonic use e.g. on IIIm is problematic), and its use on m7(b5) is quite a contemporary sound. Chord Tone (and essential guide tone) Very rare Very common and allowable in virtually all contexts A chord tone on a m7(b5). On other minor chords it’s a common extension giving a mystical Lydian minor quality. When found it’s usually on the IVm chord and on borrowed chords. Chord Tone on minor chords other than m7(b5) where it’s rare Rare even it’s in the implied key/mode of the moment, however it is usable on m7(b5) Quite common (and it’s a CT and EGT on a minor 6th), it implies a Dorian mode which is quite stable. Chord Tone (and essential guide tone) on minor7 and m7(b5). Acceptable on m6, very rare on minor (major7) Essential guide tone on minor(maj7). In a jazz idiom it’s common on a minor (implying melodic or
Root/Octave
harmonic minor). Very rare otherwise Chord tone and generally perfectly acceptable (although minor(major7) can cause clashes)
DOMINANT FAMILY Any chord with a major 3rd and minor 7th Remember that if an extension is written in the chord, it is a given, and other versions of that degree are rare. So C9(#11) won’t take a b9, #9 or natural 11. The one exception is on altered chords, which can accept both a b9 and a #9, and a b5 and #5 (but rarely a natural 9 and a natural 5th is uncommon) b9 Common unless it is a stable (non-functioning) chord. Most common on dominant chords with minor chord targets, but is still used to great effect when targeting a major chord. More rare on tritone substitutions or when a more floating quality is required. 9 Very common, although rare to see when it is targeting a minor chord through normally function. #9/b3 Very common on a dissonant functioning dominant, or if a ‘bluesy’ element is appropriate. However it’s blues use is more common on the I or V chord than on the IV 3 Chord Tone (and essential guide tone) 4 Quite rare unless in passing as it disrupts the dominant quality, unless a particularly mixolydian modal feel is required. #4 A common extension giving a floaty lydian quality. Very common on the IV chord (where it’s diatonic) and on non-functioning borrowed chords or tritone substitutions, often coupled with a 9th. 5 Chord Tone unless on a 7(b5), 7(#5) or alt. dominant, although the latter 2 of these may tolerate it. b6/#5 (or b13) CT on a 7(#5) chord. It’s also very common (as a b13) on a normally functioning dominant chord to both major and minor chords. Less common on a I7 or IV7, or on tritone substitutions. 6 (13) Very common (and it’s a CT and EGT on a 13th), however it is not as dissonant as a b13 so may not be appropriate in all contexts (e.g. when approaching a minor chord) b7 Essential guide tone in all cases 7 Very rare and rarely acceptable. Root/Octave Chord tone and always acceptable
DIMINISHED FAMILY º and º7 & chords (minor 7(b5) are in the minor family) All chord tones acceptable (and b3, bb7 are EGTs on a º7). All other tones are
acceptable (if they sound good) due to the inherent instability and dissonance of the diminished 7th chord. Diatonic NCTs are perhaps a bit more common that non-diatonic NCTs but the difference is quite minimal. Also a ‘whole-half’ diminished scale approach- whole tone above - or semitone below - a CT is a bit more common that ‘half-whole’ but again the difference is slight and context and listening is everything. Note that the above table is concerned with guide tone lines which have an inherent sustained use over the harmony. The use of melody notes over harmony is even more contextual and difficult to systemise. See ‘Melody and Harmony’ in Popular Music Harmony-An Introduction for more.
SUMMARY The above table is very difficult – and inappropriate - to memorize out of context, so here’s an overview for creating guide tone lines. CTs are (almost) always perfectly acceptable and EGTs (3rds and 7ths – or 4ths and 6ths on sus chords and 6th chords respectively) provide the ‘essential’ character and function of chords Extensions are (very generally) more common when diatonic (or from the key/mode ‘of the moment’) than otherwise but there is a great deal of contextualisation that influences their use as suggested by the table above. In short if it sounds good, it is good. And if the theory says something should work, and it is doesn’t sound right or idiomatic, then don’t use it, but do be prepared to develop your listening skills and tastes. Theory can explain why things work (or don’t) and should also adapt and be responsive to the ear. Theory also allows you to systemise knowledge and opens up all manner of creative possibilities that might otherwise be unattainable through unguided exploration. Now complete the Guide Tone Line Exercises.
