Bass technique: Franc O’Shea

This time I’m focusing on playing 7th chords on the bass. To build a 7th chord, you add the 7th note of the scale to a triad, so that the whole chord consists of the root, 3rd, 5th and 7th. Example 1 shows the many  different types of 7th chords, with the Major 7 depicted in a box with a thicker border, highlighting its status as the starting point for all forms of 7th chords, since all its notes are naturals.

Microsoft Word - Example 1.docYou will notice that 7th chords are built with odd numbers from the scale. The six boxes in example 1 highlight the six foundational 7th chord types. The mutable elements are the 3rds and 7ths, as these change the quality of the chord. For example, a Major 7th chord (1-3-5-7) with a flattened 3rd will not become Maj7b3 but a Min/Maj7. Generally, the fi xed elements are the 5ths. There are three types: natural 5th, sharpened 5th and flattened 5th. These appear in brackets in example 1.

There are 13 possible 7th chord types: Maj7, Maj7b5, Maj7#5, Min/ Maj7, Min/Maj7b5, Min/Maj7#5, 7, 7b5, 7#5, Min7, Min7#5, Half-Dim7 and Dim7. The most common 7th chord types are Maj7, 7, Min7 and Half-Dim7 since they are used to harmonise a major scale. However, others occur when harmonising the other parent scales, as shown in example 2: specifically Min/Maj7, Maj7#5 and the full Dim7 chord.

Microsoft Word - Example 2.doc

So how do we play 7th chords on a bass guitar? Just like the triads, there are shapes that use A string roots and shapes that use E string roots. Let’s start out by looking at four of the six foundational 7th chord types (Maj7, 7, Min7, Min/Maj7) that use a natural 5th. Since the perfect 5th tends to just double up the octave, it can be left out of the voicing without compromising the sound of the chord. In example  3 we start out with chords that use A string roots shown in the first four bars. Since we are using only three strings for these four-note chords, it is convenient to not use the 5th for these voicings. You will find that these chords are easier to play on the bass than the triads we looked at last month, especially in the lower positions.

Example 3

Bars five to eight of example 3 shows the E string voicings for the same chords. Instead of using the same voicings, we use open voicings that place the 3rd of the chord an octave higher for clarity, since chords on the bass sound muddy with too many low notes. As the chords with E string roots allow us to use all four strings, we could use the 5th in  these voicings as well, as in example 4. You may want to try these particular shapes in higher positions on the fingerboard as they can get muddy lower down.

Example 4

What about the Half-Dim7 and Dim7? Since both these chords contain a highly colourful diminished 5th, it is sometimes desirable to use it instead of the 3rd. Why not use it instead of the 7th? If we do that, then we will end up with a triad, but using the 7th and the b5 produces the 7th-chord sound. However, if you do choose to leave the b5th out of a Half-Dim7 chord, it will effectively be the same voicing as the Min7 chord without the 5th.

You can see the shape for the Half-Dim7 chord, using the b5th but not the b3rd, with an A string root in the first bar of example 5. In the second bar you can see the four-note voicing using an E string root. The third bar demonstrates another possibility with an E string root, this time using only three notes: the root, b7th, and the b5th an octave higher. Bars four and five of example 5 show two ways of playing a fully-diminished 7th chord using only the A, D and G strings. In bar four, the voicing uses root, b3rd and bb7th, and in bar five the voicing uses root, b5th and bb7th. The voicing in bar six includes all the notes of a Dim7 chord using an E string root, and in bar seven we see a three-note version of the same chord using root, bb7 and b3. The eighth bar shows another three-note version using the b5th instead of the b3rd but places it an octave higher.

Example 5

Example 6 demonstrates how both the A string and E string root shapes can work together to create natural voice leading between chords. A cyclic pattern is created in this chord sequence, as each root is a diatonic 4th away from the next. This is known as a cycle progression. The sequence is given in C major. The roots are going down a 5th, up a 4th, down a 5th, up a 4th and so on, as going down a 5th you get to the same note as going up a 4th – but if we just continued going up in 4ths we would soon run out of strings.

Example 6

I have used root, 3rd and 7th for all the voicings in this example, including the B Half-Dim7, but feel free to try out the root, b5th, b7th shape for this chord as well. For the A string voicings I suggest that you use the middle finger of your left hand as an anchor to play the root and for the E string voicings I suggest you use the index finger of your left hand as an anchor to play the root. As you target each chord, anchor the root note first, and then the other fingers should fall naturally into place when fretting the other notes.

Next month I will be delving further into 7th chords by looking at the more unusual types and 7th chord inversions.


Franc O'Shea photo b&w222Head of the Bass Department at BIMM Brighton, Franc has worked with artists such as Steve Howe (Yes), Lisa Moorish, and Mike Lindup (Level 42). Franc uses Jeff Chapman basses and Elites strings.


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