Hold it right there – if you’ve learned jazz within the past twenty years or so, it’s likely you’ve been taught the wrong chord tones on tonic chords.
People tend to teach from the perspective of chord-scales. Which is fine. Pretty much the first thing we’re taught is to stack our chord tones in thirds.
That naturally leads people to conclude that the strong chord tones on all chord types are root, 3rd, 5th and 7th. This is fine up to a point – while it is certainly true for minor 7th and dominant 7th chords, it isn’t really the case with tonic major and minor chords.
Let’s review what each chord tone does for a living:
- The root tells us where home base is.
- The third indicates the quality of major or minor.
- The fifth reinforces the root (or is altered to provide interest).
- The seventh indicates that the chord is active, in progress towards another chord (dominant 7th) or inactive, at rest, (major 7th)
The fact is that on tonic major and minor chords, jazz musicians have overwhelmingly used the 6th, rather than the 7th, to indicate that tonic chords are at rest, resolved. This is true both of harmony and improvised melody lines.
The real tonic chord tones are root, 3rd, 5th and 6th.
In fact, the 7th on a tonic chord has a certain abrasive quality. The reason for this becomes more clear when we consider the prospect of a tonic voicing with the root in the melody. Consider the first note of Green Dolphin Street, for instance, given here first as CΔ then C6:
Play these two basic voicings under the root and compare how they sound. The one with the major 7th in the voicing has a much less smooth feeling. The reason for this is that a dissonant minor 9th appears between the major 7th in the voicing and the melody tone above. Play just the top two notes of the first example (B and C) to hear this dissonance clearly.
Now it’s true to say that sometimes this mildly abrasive quality is actively preferred, certainly in the context of 1960s jazz onwards. Particularly with chords from melodic minor, the major 7th was increasingly used from this period onwards.
Nevertheless, if we’re talking about a “first choice” chord tone to make a tonic chord sound resolved, jazz musicians have always favoured the 6th over the 7th.
Don’t believe me? Let’s look at the evidence.
THE PIANIST’S LEFT HAND
For evidence of how jazz musicians have conceived chord tones in various periods of the music’s development, it’s highly instructive to look at what pianists have played underneath a melody or RH solo.
Ragtime, stride and swing piano voicings contained the 6th on a tonic chord, not the 7th. The typical shape is 1-3-5-6.
The bebop shell voicings used by Bud Powell and his contemporaries are possible with a 7th, but much more common is root with the 6th.
The rootless voicings popularised by Red Garland, Bill Evans and Wyn Kelly can use the 7th, but the most common shape is to play 3rd and 5th, add the 6th and complement it with the 9th.
Fourth voicings are inherently more ambiguous. Chord tones are built in thirds (apart from our new friend, the 6th), and the average hand can only span three fourths – so you’re only going to be able to include two chord tones. This ambiguity is not a bad thing – it’s actually an important part of the sound of 1960s jazz and beyond. The commonest fourth voicing for a tonic chord contains 3rd, 6th and 9th.
Again avoiding the 7th in favour of the 6th. Incidentally, for all that they are “modernistic”, these fourth voicings are really just thinned-out versions of the rootless voicings we just mentioned.
So, while pianists have certainly occasionally used tonic voicings with 7ths, the overwhelming evidence is that they have regarded the “finalising” chord tone on a tonic as the 6th not the 7th, throughout all periods of the music’s history.
THE TONIC BEBOP SCALE
The rationale behind passing-tone scales, of which the most widely applied have come to be known as the “bebop scales”, is to add consistent chromatic tones to the basic chord-scale so that chord tones coincide with strong downbeats. This makes for much stronger melodic construction.
Again, we find that the bebop scales used over tonic chords consider the chord tones to be root, 3rd, 5th and 6th (not 7th). Look at where the downbeats fall over C and Cm bebop scale:
Actually, it isn’t possible to add a chromatic tone to a tonic scale so as to emphasise the 7th. The root is a vital chord tone and a semitone doesn’t exist between root and 7th, so it’s impossible to emphasise both these tones in this kind of bebop-style scalar eighth-note line.
BLOCK CHORDS AND BASIC ARRANGING PRINCIPLES
Let’s look at the block chord style developed by Milt Buckner, George Shearing and others for harmonising a melody with parallel moving voicings. The principle is to voice chord tones as tonic 6th chords and all other tones as dominant 7b9 chords. C major:
We’ve added a passing tone so as to smoothly alternate I and V chords. (Flat the 3rd and you have the tonic minor version).
This is called “four-way close” and is also the underpinning of many different styles of arranging for horns. What we’ve effectively done is harmonise the tonic bebop scale. Again, the chord tones are considered to be root, 3rd, 5th and 6th.
The “gapped scale” sound was explored at length in the 1960s by musicians such as Coltrane, McCoy Tyner, Chick Corea and Woody Shaw. If you’re tempted to think of the 6th on a tonic as a rather vintage sound, belonging more to swing and bop than modern styles, guess again. Pentatonic scales also overwhelmingly favour the 6th and omit the 7th.
Pentatonic scales are very flexible – there are many different types of pentatonic and they can be applied over lots of different chord types.
Having said that, the basic starting point is the major pentatonic scale: 1-2-3-5-6. This pentatonic scale is a melodic resource that has been used throughout history in cultures the world over. It contains the 6th and no 7th.
Granted, there are plenty of other pentatonic possibilities over a tonic chord which do contain the major 7th. For instance, over a C major chord we can also play G major pentatonic, D major pentatonic, F# half-diminished pentatonic (these last two convert the chord to CΔ+4). It is interesting to note, however, that the overwhelming majority of these other possibilities contain the 6th as well…
Once you’ve taken this principle on board, you’ll notice it everywhere. You’ll also find the improvised lines you play over tonic chords will immediately start to sound stronger. While it is possible to emphasise the major 7th in an improvised line, the 6th often sounds more idiomatic.
So don’t believe everything you hear from teachers (including me).