How the Pros Use Inversions

A student recently asked me:

“I’m not 100% sure I get the necessity of inversions… I understand them, but when I’m playing and I need a third or a fifth, I just think of the note I need and then go up or down, which doesn’t require the extra calculation of the inversion interval… What am I missing?”

You say you “need a third or a fifth”. The crucial considerations are: do you mean the interval from your starting note and is it ascending or descending? Or are you referring to the third or fifth of a chord or scale? For example, an ascending fifth from C is G. A descending fifth from C is F. However, when you refer to the fifth as a chord tone or scale degree, in C major this will be a G regardless of whether you ascend or descend. So when you “go down” (to use your phrase) from the C to the scale’s G below, that C and G you are playing form the interval of a fourth, not a fifth (even though it is the fifth scale degree in C). So, you may be closer than you think to “getting inversions” but lost in confusion about some crucial aspects.

One such aspect is to mistake interval inversions (fourths and fifths are inversions of each other for example!) with ascending and descending intervals.

In the example above, if you do what you say correctly, you just think of the note you need and hit it either above or below the root! By doing that you actually are calculating/playing the inversions. You play a fifth ascending and a descending fourth, or, to use your other example, you play an ascending third or a descending sixth and both of those will lead you to the same note, just in different octaves.

My guess is this is what you mean: You’re playing a Bossa groove, for example, with two bars of a C chord. So you start with the root and fifth of the C chord to create your groove and to switch things up sometimes you play the G above and sometimes the G below the C. You are playing the chord tone of the fifth, in this case G. The intervals you play are an ascending fifth or a descending fourth.

In this sense it’s absolutely crucial to understand inversions. Many theory books I checked are painfully incomplete about this. They talk of C and G and then G is a fifth whether you play it ascending or descending. That is only true if you assume C major as the key. In other words, giving the correct context is important to avoid confusion. If for example the key were G major, then C to G means playing from the fourth to the tonic. Some people are sloppy with this stuff and if you don’t understand it 100%, it will come back to bite you later.

Watch the video to learn more!

Why you need to know inversions as a bassist

• The shape of the hand playing an interval is key. Kinesthetic knowing (feeling/muscle memory) is always much faster than conceptual knowing.
• Transposing: If you know the right note in both directions (ascending and descending from the root) as a shape, you have a much easier time transposing!
• [my favorite reason:] Ears! The sounds of the inversions are related (check out my Ear Confidence Course for more info here!):
  • seconds and sevenths: tense
  • fourths and fifths: open
  • thirds and sixths: sweet, romantic, pretty
  • Chord inversions. Makes it much faster to grasp those if you know your interval inversions
  • If you run out of strings or frets at any point, it helps to find the right note quickly
  • Fourths and fifths are easy. But make sure you have this down for thirds and sixths (major and minor),  plus seconds and sevenths (major and minor of course), as well.
  • As the basic building blocks of music, having a good handle on intervals is a must. Once we get into symmetric scales, extensions, alterations, melodic minor and harmonic minor and their modes – you can’t afford to have to think hard or know things in one key only (typically in the key of C)

Famous Inversion

“I wish” by Stevie Wonder shows off:

• major sixths and minor thirds are inversions of each other (Ebm)
• major thirds and minor sixths are inversions of each other (Ab)

[Side Note: The chord changes in the verses are Ebmin to Ab7,  so I notated the key signature as Db major (Eb dorian).]

Watch how using the inversion creates a cool variation and makes the groove a two bar phrase (even though the notes stay the same).

Musical Effects of Intervals

One secret that even some pros don’t fully realize, is that the inversion of intervals spans a different width of intervallic space. Using the “I Wish” example: an ascending minor third is a rather small interval. Compare that to the descending major sixth which is a much bigger jump and therefore covers a wider space. The effect of the bigger jump is more dramatic. Use with taste and to fine tune the musical effect you want to create!

If your bass line goes into a higher range because you have a jump in there and it could interfere with other elements of the arrangement, you can keep the selection of your notes and strategically reverse some interval jumps to stay in the lower range.

All About Inversions and more…