Let’s look at how intervals might be used as a way of generating melodic ideas, and how they might be in distinctive bass-lines. The best way to think of interval exercises is to consider them as a sequential pattern consisting of pairs of notes from each scale degree in turn. The pair of notes consists of the scale degree and the note that is the required interval away. Probably the first such exercise that most of us come across is thirds from the major scale, where we play the root followed by the major third, the second degree followed by a minor third, the third degree followed by a minor third and so on. The same exercise can be applied using other intervals, of course.
The benefit of such exercises is that we learn the internal intervals within a given scale or mode, deepening our understanding and encouraging us to think in terms of these intervals when looking for ideas. But other than playing exercises, how can we make good musical use of this concept? It’s certainly the case that, if overused, these ideas can sound quite glib and predictable – but used judiciously and with some variation they can provide a wealth of melodic ideas.
I suggest first that we consider four basic ways of playing any interval exercise, giving us four times as many possibilities right away. As we are playing discrete pairs of notes from the scale, the first obvious variation would be to reverse the order in which we play these pairs of notes – the interval note first followed by the scale degree. Then, by combining these two ideas in an alternating fashion, we can generate another two variations – scale note/interval, then alternating; and interval/scale note, then alternating. Figure 1 demonstrates these four approaches when applied to thirds in C major over one octave.
You will notice that, when we play either of the alternating versions of the exercise, if we continue the exercise into the second octave it can be seen that, as a result of there being seven scale degrees, the order will reverse and the second octave will commence with the first pair of notes the other way around. I recall that when I first played these types of exercise I spent some minutes wondering what I’d done wrong before realising that it just works out that way naturally.
It gets interesting when combining different intervals from different scale degrees, a concept that suggests myriad possibilities. When you consider all the possible permutations in all scales, modes and keys, it’s pretty daunting. In reality, it’s best to consider this an area to explore, discovering ideas and adding them to your vocabulary.
As an illustration of the concept, figure 2 uses a combination of 3rds and 5ths from the C major scale. Firstly, the exercise is played alternating between 3rds and 5ths and starting with a 3rd. So, we play a major 3rd from C, a perfect 5th from D, a minor 3rd from E, a perfect 5th from F, and so on. Once you have that under your fingers, you might want to try the exercise the other way around, starting with a 5th, then a 3rd, and continuing to alternate: this version of the exercise includes a diminished 5th from the 7th degree. Notice that, as with the third and fourth approaches in the first example, this is an alternating pattern, so it will reverse as you progress into the second octave – 3rds and 5ths would become 5ths and 3rds, and vice versa. If we bear in mind that these ideas can then be subject to the four basic approaches outlined in the first example, then we begin to appreciate the wealth of possibilities that this concept suggests. For instance we can alternate 4ths and 6ths using what we might term approach four – interval/scale note, then alternating – an example I have also included for you to try.
Although I have presented examples in C for ease of reading, make sure that you try these ideas in all keys.
These ideas, used carefully, can add a distinctive shape and sound to a bass-line, adding variation and colour. For instance, some of the ideas can be very useful when playing a walking bass line on just one chord, as in, for instance, ‘So What’ by Miles Davis. Figure 3 is eight bars of a walking bass line on a Dmin7 Dorian chord. Notice that the first four bars are a simple rising and falling scale pattern, and then, at bar 5, there commences a pattern of 5ths alternating with 3rds using the third approach: scale note/ interval, then alternating. This continues for three bars before the eight-bar section concludes with a descending arpeggio. Here I have tried to demonstrate how to use these ideas in creating a line, integrating them with more familiar scale and arpeggio patterns.
Finally, in figure 4 I demonstrate how one might use this concept in creating a 16th-note funk pattern, in this case on an Emin7 chord. The combination of intervals here is 6ths and 3rds, which creates a distinctive sound, the wider interval of a 6th contrasting with the 3rds. Apart from the octave Es at the start of the second and fourth bar, the entire line conforms to a pattern commencing with 6ths alternating with 3rds from the bottom E, using approach four. Note that, as both the interval used and the order of each pair of notes alternates, both of these factors reverse above the octave E – so above the octave, F# (the second degree), is the second note of a minor 6th (for example fourth beat, bar one), but in the first octave it’s the first note of a minor third (beat three, bar two).
It’s possible to take interval study and derive many variations. You will find that different intervals give a different character to a line, even where they’re from the same scale, and so these exercises encourage us to think in terms of intervals rather than simply scales or modes, ultimately broadening our range of expression.