Why the parallel *minor* pentatonic scale works so well over a *major* blues

This is a question that’s haunted me in a low-level way since I was in the eighth grade and my guitar teacher in Silver Spring MD first taught me that I could solo over the 12-bar blues changes using the parallel minor pentatonic scale. He probably didn’t use the words “parallel minor” at the time, and I only learned these years later in freshman theory/aural skills. But yes, he was right: not just the relative minor works, but the parallel minor. I knew a little about relative minor, even then. I knew that if I was soloing over a blues in C major, I could safely use the C major scale, and also C major’s relative minor, A minor, and therefore also the A minor pentatonic. But a C minor pentatonic?? Not only didn’t the parallel keys end up clashing horribly as might be expected, but the C minor pentatonic was probably the most “bluesy” sounding choice! How could this be?

While trading solos over a C blues with some cello students today, with a Music Compass on the stand demonstrating the C minor pentatonic, I finally grasped one neat reason why.

Blues Legend B.B. King

Let’s start with the chords in the C major 12-bar blues progression. We need a I, a IV and a V chord, and in the blues all three of these are typically dominant seventh chords. So, in C major, that means a C7, an F7 and a G7 chord. Since I was playing the chord accompaniment on cello, I wanted to reduce each of these four-note chords to the essential notes so my hands didn’t get tired too quickly. I reduced each chord to a dyad of just two notes — the root and 7th — to make sure I was both anchoring the root motion and supplying that dominant 7th sound so characteristic in the blues. So here’s what I was playing for each chord:

C7 (root + seventh)
F7 (root + seventh)
G7 (root + seventh)

If you take all three of these dyads consisting of root notes + sevenths, and combine the notes into one shape, you get… the C minor pentatonic!

C Minor Pentatonic

This is a big reason why the C minor pentatonic can “float” so nicely over the three dominant seventh chords of the 12-bar C major blues.

Now try building a C minor pentatonic using the Music Compass webapp, and jamming over a C major blues backing track available on youtube, like this one!

How to keep a steady beat (pulse) while performing music

In my high school string orchestra class, where we’re rehearsing Handel’s Sarabande, I’ve been having an ongoing discussion with the students about the unintended tendency of our tempo to fluctuate — rush or drag in certain sections. Some of the students immediately want to use a loud, rehearsal room metronome to keep the performance in time. My instinct is to encourage them to subdivide and to listen around the ensemble for the finest subdivision — in our case eighth notes. My sense is that we need to try listen and internalize subdivisions. “How can we internalize something if it’s not externalized first?” some of the students complain, with a certain logic.

Classic style metronome and wood stringed bass

How does metronome practice “work”, anyway? Do we have to be highly attuned to where we rush, where we drag, for it to be an effective learning process that leads to improvement in our consistency of pulse? Or does metronome practice work more by rote and repetition, ingraining a clockwork in our minds and muscles?

I asked Farsheed for his input on the issue, figuring his skills as a drummer mean that he’ll likely have some ideas. Here’s his response:

"I think the way metronome practice works is more through slow repetition that builds muscle memory. The goal isn’t to get better at playing along with a metronome like a robot, but to improve our ability to play without one. That means ideally when playing along with a metronome, you can hear it but you don’t have to pay close attention to it. If playing along with a metronome feels stressful or difficult, that’s probably a sign the tempo is too fast for what you are trying to do. Slow the metronome down to the point where you can play along in a more relaxed state of mind and so the metronome no longer feels imposing. I think issues with rushing and dragging often happen because we are not in a relaxed state of mind & body, and that anxiety causes us to overthink and causes our muscles to tense up. So, I think the idea of practicing with a loud metronome in class is not a bad idea, but maybe only at a very slow tempo to make sure the students are relaxed and that the metronome is not an elephant in the room. Then once everyone feels comfortable at the slower tempo (comfortable to the point of boredom), you can try gradually increasing the tempo and/or remove the metronome. Your idea to have students listen around the ensemble for the finest subdivision seems a bit counterintuitive as you want them to hear and pay close attention to a kind of relative ‘hidden’ metronome. That might lead to a distracted and tense performance, which may lead to more rushing and dragging. I wonder though, is your idea to focus on listening to subdivisions because students are having trouble understanding how to play the notated rhythms?

I really like Farsheed’s idea of aiming for a relaxed state of mind in which the metronome is no longer imposing, and getting there by starting well under the desired tempo. We’ll try that in rehearsals next week! In the Sarabande, our unintended tempo changes usually occur in transitions — for example the violins are playing an eighth note accompanying role, while the cello section has a melody with longer rhythms, in this case dotted half notes and quarter notes. When the roles reverse in a transition, there will be a tendency for the tempo to drag, the guilty party usually being the violins taking on the melodic role with longer tones. The idea is that keeping the listening focus on the chugga-chugga eighth notes (the finest subdivision) before and after the transitions will help keep the tempo consistent. String players are renowned for taking their sweet time with long tones in the melody, and in their bliss, blocking out all else. I know because I’m one such string player myself!

Two-Part Harmonies in Pop Music (Part 1)

I want to take a closer look at vocal harmonies in pop music– specifically, which intervals are frequently used between voices? Which are more unusual? What are the effects of the different intervals in terms of the character of the music? I’ll explore these questions this in a series of posts on vocal harmonies.

After making a short cello arrangement of Major Lazer/DJ Snake’s tune Lean On, I’ve started listening for the use of perfect fourths (P4) and perfect fifths (P5). Fourths and fifths sound “open”, “hollow” and “scary” to me. The uses of fourths and fifths in the examples below probably violate prohibitions against “parallelism”, but that’s another subject for a different post!

Perfect Fourth (P4)
Perfect Fifth (P5)

Danish singer MØ uses fourths and fifths throughout Lean On. The first example is right at the beginning: “…innocent, remember, all we did was care for eachother….” In the arrangement below, the piano RH (second line) is playing the fourths and fifths.

Another tune that came to mind when I tried to think of any recent (and not-so-recent) pop tunes with “hollow” and “scary” vibes was Lorde’s song Royals. Sure enough, it also has lots of fourths and fifths in the vocal harmonies, here also taken by the piano RH (middle line). “…I cut my teeth on wedding rings….”

Are there any other good examples of pop tunes that make use of fourths and fifths in the vocal harmonies? The genre of bluegrass is coming to mind for some reason. Are these intervals more common there? Jazz too might have more examples of parallel fourths and fifths, though perhaps more frequently between instrumental rather than vocal lines. Maybe also soul and gospel harmonies?