Musical simple: Groove Is In The Heart

In college, I played in a cover band called Harsh Mouse (because the band members all lived in Marsh House.) One of the high points of our repertoire was this song.

The irresistible groove at the heart of this track was sampled from “Bring In The Birds” by Herbie Hancock, from the score of Michael Antonioni’s film Blow-Up.

Herbie’s tune is fun in that Austin Powers way, but the two-bar intro is its best feature. Deee-Lite had the good sense to recognize that if you loop the intro, you get a reliable dance-floor-filler.

The “Groove Is In The Heart” riff is more or less a steady stream of eighth notes over a simple chord progression, A♭7 and D♭7 alternating back and forth. The rhythmic excitement of the riff comes from the way that it anticipates the chord changes.

You conventionally expect important musical events like chord changes to happen on strong beats. The strongest beat in a measure is beat one, the downbeat, and that’s the likeliest place for a chord change to happen. The first note of the riff is A-flat, the root of the A♭7. It falls on the downbeat, right where you expect it. But then at the end of measure one, the riff lands on D-flat, the root of the D♭7, an eighth note earlier than you’re expecting it. At the end of measure two, the riff walks chromatically up to A-flat, once again anticipating the next A♭7 chord. The resulting metrical instability gives the groove its deliciously off-kilter feeling.

Let’s look more closely at the chord progression. Simple though it is, this progression is hard to explain using the rules of Western tonal harmony. Dominant seventh chords are “supposed” to resolve down a fifth, so the A♭7 should resolve to D♭. Indeed it does, so it would appear that D-flat is our home key. But the D♭7 chord is a dominant seventh too, and tonal theory says that it’s supposed to resolve to G♭, not lead us back to A♭7. Anyway, regardless of the chord qualities, A♭7 feels like the “home base” chord because of its metrical position and emphasis. So we must be in A-flat. But are we in A-flat major, or minor, or what? Tonal theory can’t tell us.

“Groove Is In The Heart” may not be tonal, but maybe it’s modal. Do the two chords imply a mode? We could think in jazz terms and treat A♭7 as emerging from A-flat Mixolydian mode. The scale is shown below, on the chromatic circle on the left, and on the circle of fifths on the right. The blue lines show the A♭7 chord.

The D♭7 chord would similarly suggest D-flat Mixolydian mode. The purple lines show the D♭7 chord.

Notice that the two scales are almost identical. You could rotate either of them one notch on the circle of fifths to get the other. Closeness on the circle of fifths is a good proxy for harmonic relatedness generally.

When you combine the pitches from A-flat and D-flat Mixolydian together, you get A-flat Mixolydian with an added flat third (C-flat, which is the same pitch as B). This scale is known in jazz pedagogy as the A-flat Bebop Dorian scale.

So, there’s our mode. Problem solved, right? Not quite. When you look at the vocal melody in the chorus, there’s a note that doesn’t fit: the D natural in the fifth measure.

The chorus melody is a classic example of the blues scale.

Remember how I said that closeness on the circle of fifths is a good proxy for harmonic relatedness? By that standard, D natural is the weirdest note possible in the key of A-flat–It’s on the exact opposite side of the circle from the root.

The blues scale is generally inexplicable in Western tonal theory terms. It has the flat third characteristic of minor tonality, yet it’s frequently used over major and dominant chords, as it is in “Groove Is In The Heart.” Really, the tune isn’t in A-flat major or A-flat minor. It’s in A-flat blues tonality. That’s not a standard term in music theory, but it should be. If a harmonic practice is this common and this well-loved, we need to adapt our music theory to be able to accommodate it.