We’re taking another big step forward in our harmonic fluency journey by looking at sounds that add motion, tension, and arrival in a very direct way. b5 substitutions, often referred to as tritone substitutions, along with what I call “Approach from Above/Below”, both give us powerful tools for creating movement without overcomplicating the harmony. These sounds show up everywhere in jazz, blues, and American popular music, and once they are under your fingers they begin to feel natural and intuitive. This is the kind of material that helps your playing sound intentional, connected, and alive in real musical situations.

Key Learning Outcomes and Topics Covered

• Understand what a b5 substitution is and how it relates to the tritone
• Learn how and why b5 substitutions create strong half-step resolutions
• Apply b5 substitutions as replacements or passing chords
• Understand the concepts of approach from above/below
• Apply approach techniques to blues, ii–V–I progressions, and static harmony
• Use bass motion and voice leading to create smooth harmonic movement
• Combine b5 substitutions with companion minor, diminished chords, and inversions
• Develop musical judgment by testing ideas with your ear

Introduction

This lesson brings together two closely related ideas that are often taught as separate theory topics but are deeply connected in sound. The b5 substitution, sometimes called the tritone substitution, has long been part of the jazz vocabulary, while approach from above/below offer a more ear driven way of understanding the same harmonic motion. Rather than getting stuck in terminology, the focus stays on how these sounds function, how they feel, and how they can be applied musically across standards, blues, and solo guitar settings.

Lesson Summary

The lesson opens with a clear explanation of the b5 substitution. Two dominant chords whose roots are a tritone apart share the same essential inner notes, the third and seventh that form the tritone. For example, A7 and Eb7 contain the same core pitches. Because of this shared structure, either chord can resolve to the same destination, with the most noticeable difference being the bass note. That half-step bass motion is a major part of what makes the sound so compelling.

From there we explore how b5 substitutions function in context. They can be added alongside the original dominant or used as a complete replacement. Longer progressions such as ii–V–I forms offer especially good opportunities, allowing the harmony to flip between the original dominant and its b5 substitute or pass smoothly through both. It should also be emphasized that b5 substitutions do not need heavy alterations. Keeping them relatively straight often preserves their connection to the original chord.

The concept is then broadened beyond dominant chords. By thinking in terms of bass motion rather than chord labels, the same b5 relationship can apply to major and minor chords as well. Sometimes the substitution appears as a full chord, and other times it shows up simply as a bass note moving underneath a stable voicing. This flexibility makes the sound usable in many musical situations.

At this point, the lesson reframes the idea through approach from above/below. Any chord can be approached from a half-step above or below, often for a beat or two before arrival. Approach from above tends to create a strong V to I feeling, closely related to the b5 substitution. Approach from below creates a leading tone effect, more like a IV7 sound resolving home.

We also explore how approach chords can be dominant chords, the same chord quality as the destination, or diminished chords when approaching from below. Attention is given to voice leading, especially the movement of the outer voices. Using contrary motion helps the harmony feel smoother and more musical instead of heavy or mechanical.

These ideas are applied to blues, ii–V–I progressions, Rhythm Changes, and static dominant harmony. We hear how bouncing between a chord and its approach can create motion even when the harmony itself is not changing. The lesson also revisits earlier concepts such as companion minor, showing how a dominant can be preceded by its companion minor to create a suspension and release effect before resolving.

Diminished chords are introduced as another form of approach from below, taking advantage of their symmetrical nature and multiple inversion possibilities. When combined with inversions, b5 substitutions, and approach tones, the harmonic possibilities expand dramatically without requiring a large number of new shapes.

The emphasis stays on using these sounds in music, not just understanding them on paper: learn the basic changes first, then test these ideas with your ear. Use them differently depending on whether you are playing solo, in a duo, or with a bass player. Sometimes these movements belong in the arrangement, and other times they live entirely above the bass line as part of spontaneous comping or solo playing.

Soundbites

• “If it sounds good, it is good.”
• “It’s all about motion. It’s all about landing the chord of the moment in a way that makes sense to your ear.”
• “The trick is to test it out with your ear.”
• “All of these devices can lead us to a lot of variety and good sounds.”

Closing Thoughts

b5 substitutions and approach chords give you some of the most flexible and expressive tools in harmonic playing. Whether you think of them as b5 subs, approach from above, or approach from below, the goal is always the same: making the harmony move in a way that feels natural and satisfying. Take these ideas one song at a time, listen carefully, and give yourself permission to experiment. Trust your ear, stay musical, and let these sounds become part of how you hear harmony rather than just something you think about.

Keywords

• Harmonic fluency
• Reharmonization
• b5 substitution
• Tritone substitution
• Approach from above
• Approach from below
• Dominant chords
• Jazz harmony
• Blues harmony
• ii–V–I
• Voice leading
• Bass motion
• Half-step resolution
• Companion minor
• Diminished chords
• Chord substitution

Downloads

b5 Sub & Approach from Above/Below PDF