When it comes to playing bass, it’s easy to stick to specific patterns, rely on our ability to provide the musical foundation with the root and the fifth, and leave the chord knowledge up to the guitar players. Although there are musical situations where playing the root and the fifth is appropriate, it is essential for bass players to understand chord qualities (this goes for all music, not just blues). This column is going to focus on the difference between major and minor chords in blues as well as different types of minor blues chord progressions.
First and foremost, classic blues progressions rely on the use of dominant 7th chords, or a chord that is built with the root, major 3rd, 5th, and flat (dominant) 7th. Typically, the first “blues bass line” that someone learns will go “1, 3, 5, 6, b7” and then descend. In the key of C, the corresponding notes would be C, E, G, A, Bb. This bass line has an unquestionably major tonal quality and clearly outlines the dominant 7th chord. In most “shuffle” feels, the same bass pattern can work over all three chords in the progression since each chord is a dominant 7th chord. Therefore, you can start the pattern on the I chord (C7), then move the same pattern over to the IV chord (F7: F, A, C, Eb) and the V chord (G7: G, B, D, F).
Other blues bass lines will incorporate the minor third even though the chord being played is a dominant chord. Although it may seem counter-intuitive, the tension that is created is characteristic of the “blues sound.” Manipulation of the 3rd of the chord (sliding or bending the note) gives you the freedom to play a minor third over a major chord and have it sound “bluesy.” This is one of the reasons why the blues scale (or minor pentatonic scale) has a minor third instead of a major third. We’ll go more in-depth with this in a future column.
With minor blues chords, the third is flatted and the standard shuffle bass pattern will sound dissonant and out of place. The major third will stick out like a sore thumb and you’ll most likely get the death stare from the guitarist. Therefore, think about creating a bass line with the root, minor 3rd, 5th, and dominant 7th (C, Eb, G, and Bb in the key of C). Certain bass patterns omit the 3rd altogether and stick to using just the root, 5th, and dominant 7th over both major and minor chords. If you have a difficult time distinguishing major from minor (in some blues songs it may not be too obvious), you’ll be less likely to clash with the chords being played if you create a bass line with the other “safe” chord tones.
An interesting quality about minor blues progressions is that, sometimes, not all chords in the progression are minor. The I chord will always be minor but the IV and V chords may be dominant 7th chords. For instance, let’s say the I and IV chords are both minor, so in the key of C, the chords would be Cm7, Fm7, and G7. It is also common for all of the chords to be minor (the G7 would then be a Gm7). To figure out what chords are in the progression, listen closely to the chord qualities, ask someone in the band, or pay attention when the leader describes the song…they may say “all minor chords.” While you can still use a bass line that excludes the 3rd over all of these chords, be mindful of this if you’re soloing or if you’re using passing notes to transition from chord to chord.
One common mistake that people make is the transition from the minor I chord to the IV chord. The natural tendency is to play the major third of the I chord as the leading tone to the IV chord. Since it is a half step away from the following chord, it adds direction to your bass line and anticipates the upcoming chord. This works well for major blues but it is a big no-no for minor blues. Since this involves the major third of a definitively minor chord, it will create dissonance and demonstrate the fact that you’re unaware of the chord quality. In this situation, using the fifth of the chord (which is a whole step away from the IV chord) is a better transition note to play off of.
As I’ll reiterate time and time again, the best thing you can do in any musical situation is to listen. You’ll be able to hear dissonance if you play a note that doesn’t fit. At the same time, you’ll recognize that something works by hearing it within the context of the other instruments. Remember that not all blues progressions are alike, but your ability to anticipate what some of the options are will help you distinguish one kind of progression from another.