This month I will be continuing my series of columns on playing chords on the bass guitar by looking at playing 7th chords with altered 5ths and 7th chords in 2nd inversion. Last month I looked at retaining the sound of 7th chords that have perfect 5ths in their voicings using just three notes, and demonstrated that the perfect 5th tends to double up the root note and can be discarded, leaving the integral components (the root, 3rd and 7th) to convey the sound of the chord.
But what if the chord has an augmented or diminished 5th? How can we best preserve the flavour of chords with altered 5ths when using only three notes? I demonstrated last month that the root note is integral to the 7th chord, because if you discard it you are left with only a triad. For example, a Cmaj7 chord would comprise the notes C, E, G and B. If you discarded the root note C altogether, you would be left with the notes of an Emin triad: E, G, and B. This would obviously work as a substitution for the Cmaj7, but it is an Emin chord and not Cmaj7 itself. Last month I did look at a couple of examples of three-note chords being used to conserve the sound of a 7th chord: this was with half dim7 and dim7 chords. I explained that by replacing the b3rd of the half dim7 chord with the b5th, and retaining the root and the b7th, the sound was, to a degree, preserved. I also demonstrated this same process using a fully diminished 7th chord.
This month I will extend this idea and demonstrate that the same principle is applicable to all 7th chords with altered 5ths. Since no thirds are used in these voicings, some of these shapes will work for more than one 7th chord type. The major 7 shapes will also work with min/maj7 chords and the dominant 7th shapes will also work with minor 7th chords.
Example 1 demonstrates these omitted 3rd voicings, using root, altered 5th and 7th with A string roots. Included in the penultimate and final bar are the half dim7 (the same shape as the 7b5 and min7b5 chords with no 3rd) and dim7 chords respectively. Example 2 demonstrates the same principle of using just the root, altered 5th and 7th, but utilises open voicings for clarity, by placing the altered 5th an octave above the 7th and using the E string for the root. This example is shown from the root G at the 15th fret of the E string, as some of these chords can be difficult to play in lower positions.
Last month, I also looked at all 13 7th-chord formulas, including ways of playing the more common ones. Since 7th chords contain four notes and we are looking at building 7th chords on a four string bass, the most convenient way of playing all the notes of 7th chords in root position is to use E string root notes. Example 3 is an exhaustive demonstration of the 13 types of 7th chords, using all four strings with the root on the E string. These examples use the G at the 15th fret of the E string, but remember that once you have the shape down, you can move this shape to other roots. It is also worth noting that you may occasionally come across other ways of labelling these chords, such as the half dim 7 chord at times being called min7b5, and the maj7#5 chord sometimes being labelled as augmaj7. For a detailed exposition on chord nomenclature see my article back in BGM 60.
You may find some of these chords difficult to play, and that they work better in the higher registers, not only technically but sonically as well, since four-note chords can quickly become muddy-sounding in the lower register of the bass guitar. Since all the possibilities are shown here, you may find some of the chords sound undesirable, but most work well if played in the right context, for example as dramatic effects or for voice-leading purposes.
Having seen that it is possible to fully play all the 13 7th chord types using all four strings with root notes on the E string, you may well be asking yourself if it is also possible to play 7th chords using all four strings with the root note on the A string, and another chord tone as the deepest note, essentially creating an inversion. This is easily achieved by using the usual three-note A string root shapes that have root, then 3rd and then the 7th on the A, D and G strings respectively, and then placing the 5th below them on the E string. Example 4 demonstrates the full range of possibilities. You will note that all these chords are in 2nd inversion as they have the 5th as the lowest note.
My article on triads in BGM 87 explains that inversions have another note in the chord as the deepest-sounding note other than the root. We saw that there are two inversions and the original root position with triads, and it should be apparent that 7th chords, which contain one more note than triads, can be inverted three times as well as be in root position. Example 4 gives you a taster of the 7th chord inversions that we will be exploring next month.