Blues Parallelism

Blues Parallelism

Ever since last year when it clicked that parallel chord movements are probably an essential part of blues, I’ve been working them into my bass style. As a musical force, parallelism is probably familiar to jazz listeners from the style of guitarists like Wes Montgomery. Check out his playing from 4:16 in this iconic performance.

What I’ve been trying to do relates very much to jazz guitar and even more so blues guitar traditions. I remember how refreshing it was to hear Simon Jermyn once point out that bass guitar and guitar are closely related instruments. Rather than model my approach on double bass or synth bass, I’ve often taken guitaristic paths in my playing. So, to my mind, the parallel chord movements I’ll look at today are completely native to fretted bass guitar.

“Parallel”, for anyone unfamiliar with the term, means that each new chord has the exact same inner structure (distance between its component notes) as the one before, but starting in a different place. So, each note moves in “parallel” with the others to reach the corresponding notes in the new chord.

The reason this is native to guitar and bass guitar, is that you can form a chord shape, and then easily slide the whole shape up or down to make a new chord. (You’ll see it in the solo I do at the end of the post.)

The first time I really noticed parallelism was in electro house tracks with basslines doubled in major 10ths. Remember this one?

But, actually, since childhood I’ve loved hearing blues slide guitar which is built on completely parallel “open-tuned” chords sliding up and down. Guys like the hippy blues savant Alan Wilson (seriously check out that magnificent performance by his band Canned Heat!) or George Thorogood.

Not all chord shapes are equal for this application. The strongest shapes are those that resemble part of the overtone series. This similarity causes the notes to interact and buzz. Gerhard Kubik calls acoustically resonant chords like this “timbre-harmonic clusters”.

D Harmonics to 11th

So, the first interval (counting up from the bottom note) in the series is the octave. Wes Montgomery is famous for his use of parallel octaves, for example at 2:50 in the first video above. But I don’t particularly like the sound of them on bass. This is partly due to the lack of a satisfying way of sounding them – Wes strums them with a muted string between the root and octave, but that doesn’t work for me. Also, they don’t achieve that chiming sound in the bass’s register.

The next interval is the perfect 5th found between the second and third harmonics (D and G). This one is, again, completely guitaristic – the “power chord” of rock and metal. As an interesting demonstration of a distinctive resonance, if you play a power chord on bass or guitar with distortion, a strong difference tone an octave below appears.

(Sorry for the poor sound quality by the way – I’ve upgraded my microphone but forgot to plug it in here.)

Without distortion, the phenomenon is much weaker, but still noticeable as an extra fatness/bassiness at gigging volume levels. (Actually I think that’s due to the slight distortion in the preamp stage of my amp.) So I do use power chords sometimes at gigs to augment a simple bassline.

Okay so some quick thoughts on the use of the other intervals available… 4ths are very buzzy and strong, and obviously easy to play on an instrument tuned in fourths. Major 3rds are strident and bright, sometimes overwhelmingly so, but it can be used for some parallel cliches. In particular, the blues scale fragment b5 4 b3 can be harmonised a major 3rd away by b7 6 5, another bluesy cell.

Another interval I use a lot is the 10th – it’s good for “prog house” or “electro house” sounds. One interesting thing about lines consistently harmonised in major 10ths is that it becomes unclear whether the top or bottom note is the “main” one, despite the fact that a single 10th interval definitely sounds like the root is the bottom note. Try it!

Minor 3rds are a flexible interval for parallel cliches, and I wrote an article about one of those. Major 6ths are used in the classic blues chromatic descending run, but can also be extended into half-whole diminished sounds like Scott Henderson’s. Minor 6ths basically can work as the 3rd and octave of a dominant chord or its 2nd and b7th. Minor 7ths sound good but can only really function as the 1st and b7th or the 3rd and 9th of a dominant chord. So minor 7th and minor 6th parallelisms in blues are basically targeting these landing points.

An interesting larger shape is one using the fourth, seventh and ninth harmonics, which ends up as a root, minor 7th and 9th (a dominant 9th with no 3rd or 5th):

9th no 3rd no 5th

This shape has a lovely resonance. Other 3-note shapes that are nice for parallelism are the 3rd inversion of a major triad (fourth on the bottom) and 2nd inversion of a minor triad (fourth on top). These are both particularly compact shapes on bass. And of course the skeletal dominant 7th, 1st 3rd b7th.

I busted a blues solo using many of these shapes in parallel movement. Have a listen and let me know what you think! I’ve timelined the appearance of different chord/interval types below.

0:02 6th

0:06 minor 3rd

0:12 minor 6th

0:22 dominant 7th (no 5th)

0:27 minor 7th

0:31 major 3rd

0:47 4th

1:02 major 10th

1:08 dominant 9th (no 3rd no 5th)

Thanks for reading/watching!


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