Music Theory for Harmonica Players Part 14 – Playing the Changes, 7ths

In the last two posts we’ve examined playing over changes using root notes, then 3rds and 5ths. That just leaves the 7ths.

Firstly a reminder that when we talk about 7th notes we’re technically talking about flat-7ths (b7ths). That’s the 7th note of the scale flattened by a semi-tone. Flatting the 7th is so common that by convention we just say 7th (more information on 7th notes in part 10).

Using 7ths requires a little more care than 3rds and 5ths. You can think of the 7th note as sounding very bluesy. That is to say that it’s got a slightly harsh, jarring character but it’s a big part of the character of the blues.

That means that if you’re playing along with a very dark, mean, bluesy sounding backing the 7th notes are going to fit right in. However, if the backing has a more light, jaunty feel, like many upbeat jump and swing blues tunes, 7th notes will tend to sound quite out of place.

Basically, if the band are playing 7ths, go ahead and use them too. If not, they are best avoided or used only sparingly. There are some examples of both below to illustrate this.

Let’s get our charts out again for reference. Firstly our chord chart, including 7th notes.

And here’s our 12 bar blues reference.

I’m going to assume you’ve memorised your C harmonica by this point because I’m tired of nagging.

So if we look at our G chord we see that the 7th note is an F. That’s available on 2 draw whole step bend, 5 draw and 9 draw.

The 7th of the C chord is Bb. That’s available on 3 draw half step bend and 10 blow whole step bend.

And lastly, the 7th of the D chord is C. That’s available on 1 blow, 4 blow, 7 blow and 10 blow.

The backing track we’ve been using works with 7ths so let’s use it again.

In the example below I’m playing 5 draw (F) over the I chord, 3 draw half-step bend (Bb) over the IV chord and 3 blow (C) over the V chord.

Sounds pretty good. And the 7ths really help push a bluesy feel.

In this next example, I’m playing the 7th notes over a much lighter, more upbeat backing.

The 7ths I’m playing stick out a little and don’t sound terribly musical or satisfying.

The take-away idea here is that your root, 3rd and 5th notes will always sound good. You can use them without fear, safe in the knowledge you’ll get a good match and sit well with the band.

Knowing when it’s safe to use 7ths takes a little bit of experience and ear training. If the band sounds gnarley and bluesy then you’re safe to use as many 7th as you like – the more the better in fact. Whereas if you have a more upbeat, happy or major sounding backing use those 7ths with care or not at all.

Hope that was fun. Next time we’ll look at chord arpeggios.