A Slash Chord is a type of chord symbol in music that indicates a chord played with a specific root/bass note on the bottom. In this article, we'll discuss the practical applications of slash chords in our writing and the scales that go with each of the slash chords!
Building a Slash Chord
There are 2 parts that make up a slash chord:
- A chord.
- A specific bass note.
A chord could be any chord, but most often with slash chord harmony, it will be either a major or minor triad.
A specific bass note could be any note of the chromatic scale. It doesn't have to be a chord tone. The bass note will always have some sort of relationship to the chord above it, which we'll get into later when we discuss slash chord-scale relationships!
The slash chord is written as:
So, for example, if we have a C Major triad over an F♯ root, we'd write it as:
So we know how to build and write slash chords. Let's look at some practical applications.
It's always important to ask “how can I use this?” when learning music theory (or anything for that matter).
So how can we use slash chords in our compositions?
Well, there are 3 main compositional techniques that have to do with slash chords. They are:
- Writing with inversions of chords
- Walking a bass line
- Holding a pedal
Let's discuss each of these in a bit more detail.
Inversions of a Chord
This is when the bass note is a chord tone. By explicitly stating which chord tone we want in the bass, we give a better sense of how the chord should be voiced.
For example, if we have Am/C – “A Minor over C”
A Minor has the notes A C and E. By putting C in the bass, we are putting the third at the bottom and giving a stronger sense of how the chord should be voiced.
Note that this doesn't necessarily tell us that we're in first inversion since we don't know exactly how the A Minor chord is voiced above the root note of C. However, the bass is a very important part of the chord, making this specific type of slash chord important in writing and composition!
Walking a Bass Line
This is where slash chords get interesting in composition. By writing with slash chords, we have the opportunity to show a specific bass line under chords.
To keep this example tidy, I won't change the chord part. I'll only change the bass notes.
For example, let's take our a C Major triad and walk a bass line of A, A♭, G, G♭, F under it. The slash chords would be written like this:
C/A C/A♭ C/G C/G♭ C/F
And that explicitly tells us we have a bass line moving downward through the chromatic scale.
This is a quick way to combine chords and bass lines in one sheet. And it's a cool way of thinking about combined harmony.
Holding a Pedal
My favourite use of slash chords is to modulate over a pedal point.
For example, we could hold F as the bass note and change chords over top of it:
E♭/F D/F D♭/F C/F B/F
In fact, I use these exact chords in the first half of the chord progression in my track Salt Lamp. Check it out:
Salt Lamp is from the album Fine Dining With An Octopus.
I personally love pedal points. Try modulating through different slash chords and see what you come up with!
Next, let's take a look at what scales could we potentially use to write melodies over the above chords? Let's dive into it!
Slash Chord/Scale Relationships
In our study of chord-scale relationships, our aim is to find which scales and modes fit over which chords in order to consciously build stronger melodies and improvisations.
Slash chords present a different way of writing and thinking about chords and harmony. They give us a defined root which is helpful in naming a compatible scale. And sometimes, a slash chord is the neatest way of writing and thinking about a certain chord.
Let's first look at an example. We'll take our previous example of C/F♯.
So that's a C major triad (C E and G) over an F♯. Let's look at our intervals and build compatible scales around them:
- F♯ is our root
- G is a ♭9 (or ♭2) above F♯
- C is a ♭5 above F♯
- E is a ♭7 above F♯
So, based on F♯, we have the scale degrees of:
1 ♭2 ♭5 ♭7
C/F♯ sounds like this:
Now we ask ourselves which scales have those intervals in them?
Well, to name a few (other than the chromatic scale), we have (based on F♯):
All the above scales (starting on F♯) play well over a C/F♯ chord since they contain the intervals of the chord C/F♯!
Another way of looking at this chord is as C Lydian with the characteristic ♯4 is in the bass. But since the F♯ is in the bass, it gives more of a Locrian sound within diatonic harmony. If the F♯ was sounded above the C major triad, I would definitely call it C Lydian.
With that being said, I will present some tables here with C major and C minor triads over each of the 12 possible chromatic bass notes complete with the scales that can be played over them.
The scales and modes in the table are based on the bass notes of the chord and are sourced from the following scales:
- Octatonic Scale
- Major Scale
- Melodic Minor Scale
As an exercise, I'd encourage you to find all the scales that would fit each slash chord (similar to what I did with C/F♯). This is not necessary to understanding slash chords and their relationships with scales, but could be an interesting theory practice.
Without further ado, here are the tables:
List of C Major Slash Chords With Scales
List of C Minor Slash Chords with Scales
Have some fun with these slash chords and their corresponding scales!
Slash chords are an interesting concept to think about when composing music. I encourage you to think about the possibilities of slash chords in your writing!
Are there any compositional techniques you enjoy implementing that involve slash chords? Please leave a comment, I'd love to hear from you 🙂
As always, thanks for reading and for your support.