Simon Trask delves further into the realm of the jazz bassline in Part 5 of our series. The underculture flows on...

This month's examples develop the 'walking' bassline theme which we began last month. You may already have noticed that the harmonies I'm using in these examples go beyond mere sevenths. After some consideration, I decided there was no way I could keep the harmonies simple where they shouldn't be - that would just be shortchanging those of you who can read more complex chords, as well as those of you willing to learn. Besides, the chords I've used here aren't only 'jazz chords' - you can use some or all of them in other styles of music, too. Acquiring a richer harmonic vocabulary can only be of practical benefit (unless you play speed metal, perhaps!).

And so to a few practicalities of chordal notation for those of you feeling your way. First, a letter immediately followed by a number (as in, for instance, A13) indicates a dominant chord ie, the third of the chord is major (C# in A), the seventh of the chord is minor (G in A). Second, an upper-case 'M' indicates a major chord (major third, major seventh) while a lower-case 'm' indicates a minor chord (minor third, minor seventh). The intervals given in superscript indicate alterations to the 'natural' state of the chord (eg. a sharpened fifth or a flattened ninth), while slashes (as in the third, fifth and sixth chords of Example 6) indicate that the chord to the left of the slash is to be played over the note to the right of the slash (eg, an E minor 7 chord over an A note).

As with last month's examples, set up an acoustic bass/acoustic piano split around D/Eb above middle C on your keyboard, so that (ideally!) you can play the bassline with the left hand and the chords with the right. The examples all use the 'play an octave lower' symbol (the figure of eight hanging from the bass clef), but if you transpose the keyboard down an octave you can play as written.

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In Example 1, bar two repeats bar one a tone higher. The chords for the most part follow a 'cycle of fifths' progression, the key aspect of which is a dominant chord leading to a major, minor or dominant chord whose root note is a fifth lower or fourth higher (remember last month's Example 7). In its role of underpinning each chord, the bassline sticks to chordal notes, but also emphasises movement to (and therefore helps reinforce) the root note of each chord. Thus, you have C# moving up to D, C natural moving down to B, and D# moving up to E.

In Example 2(a) the bassline notes in bar two are again a transposition of those in bar one, but in this case the chord progression isn't a transposition. The E in bar one and the A in bar two are both passing notes, but they also happen to be the ninths in the respective chords they underpin. The Bb and C# in bar two are respectively the flattened ninth and the major third of the fourth chord - this is the only instance in all these examples where the root of the chord isn't used in the bassline.

An alternative bassline could have the A and the Bb notes in bar two switched; this would put the root of the fourth chord in the bassline (A), while the Bb would become the minor third in Gm9. On reflection, I think maybe I prefer this bassline. Example 2(b) gives another possibility, with the fifth of Fm9 (C) substituting for the third (Ab). This makes C and C# the two highest notes in the bassline; as such they take on a degree of accentuation, and in terms of the overall shape of the bassline they lead nicely to the D.

Examples 3(a) and 3(b) illustrate two possibilities for the same chord progression. In 3(a), the chord progression and the bassline in bar two once again parallel bar one (only this time transposed down a tone). In 3(b), Db substitutes for F on the fourth beat of bar one, resulting in a downward semitone progression from Db to C which reinforces the latter rather effectively, and gives a sense of 'onward rush' to the music - it also parallels the Eb-D progression from bar two back to the start of bar one (or bar three).

I don't want to labour a harmonic point here, but the Db also turns the G7#5b9 chord into a Db9 chord. As chords become 'twisted' by means of 'alien' flattened and sharpened notes, so they become more ambiguous and can take on more than one harmonic identity, as here.

The basslines in Examples 4(a) and 4(b) underpin a characteristic 'turnaround' chord progression (ie. one which leads back to its beginning, harmonically). For the most part the progression is another 'cycle of fifths' job. Here the bassline emphasises semitone movements to each root note. The Ab in bar two of 4(a) isn't part of the Dm9 chord it underpins, but as it's a passing dissonance you may not feel that it causes problems. However, you could minimise its impact by changing the bassline to that given in 4(b); the rhythm here also propels the bassline forward more.

Examples 5(a) and 5(b) slow down the rate of harmonic movement to one chord per bar, while using virtually the same chord progression as Example 4. The bassline can now unfold in a more leisurely fashion, with more use of passing notes to give the line an undulating quality. Notice how the bassline in 5(b) has been changed subtly from that in 5(a) in order to reflect the slightly different chords used in bars two and four. The change in bar two introduces something we haven't encountered yet in this series: a triplet rhythm. A triplet is simply three notes in the time of two, as you can see - the quarter note is evenly divided into three triplet eighths. This creates a sensation of 'tumbling' into the third bar. Actually, if you've been 'swinging' your dotted eighth notes in true jazz style you've already been dabbling in triplet rhythms.

By now you should be familiar with the melodic and harmonic methods of construction used to produce Example 6 - though the chord progression is rather different from the more straightforward cycle of fifths on which most of the preceding examples are based. In bars five and six I've gone for a dramatic leap up of a minor seventh, which in turn highlights a short minor-third motif, G-E, paralleled in bar 6 as A-F#. In the final bar, the dotted eighth-note rest followed by the snappy 16th-note G breaks the regular quarter-note rhythm and propels the bassline nicely forward on its downward run to and through the C of bar one (bar nine).

Finally, Example 7, a jazz ballad (...well, part of one). Take this at around 90bpm (or as slowly as you need to!). Although there's the occasional touch of walking bass, what's more important in this musical context is a rhythmic ebb and flow which allows the music to breathe. There's a subtle interaction going on in this piece between the chord progression and the rhythm and melodic shape of the bassline - for instance, in the way that the bassline works towards a point of harmonic repose in bars seven and eight.