Unit 42 · Advanced

Reharmonization and Substitution

Generate alternatives while preserving melody and direction.

Lesson
Change the harmony without betraying the melody
Estimated time
160 minutes
Status
Previewing
Preview available

Complete the required prior unit before this unit can be marked complete. You may still read and try every activity.

What you will learn

Use diatonic substitution, secondary dominants, tritone substitution, modal mixture, and pedal tones while preserving melody and phrase direction.

Why this matters: Reharmonization is not showing off chord knowledge. It is choosing a different route for the same melody while keeping the listener oriented.

Before you begin

Diatonic function · Secondary dominants · Modal mixture · Extended chords · Voice leading

The melody is the contract

A reharmonization must account for the melody note, phrase goal, bass motion, and style. If the new chords fight the melody without a reason, the change is not stronger.

Use substitutions by function: tonic family, predominant replacement, dominant intensification, modal mixture, tritone substitute, or pedal point.

Progression · Key C · 4/4

Original and reharmonized route

Original 1CI · 1
SubstituteAm7vi7 · 6m7
PredominantDm7ii7 · 2m7
Dominant subDb7subV7/I · b2-7 to 1

Am7 can substitute tonic color, and Db7 can substitute for G7 through tritone motion into C. The melody must still fit or resolve.

1 · Model

Observe: melody-preserving reharmonization

Observe stage for melody-preserving reharmonization, with instructions and success criteria stated in text.

  1. Observe the original melody and harmony.
  2. Hear one functional substitute and one dominant substitute.
  3. Compare a supportive reharm with one that fights the melody.

Help you can use: Complete model · Decision labels

  • Melody remains clear.
  • Substitutions have named function.
  • Bass and phrase direction improve or change for a clear reason.
2 · Guided attempt

Try with prompts: melody-preserving reharmonization

Try with prompts stage for melody-preserving reharmonization, with instructions and success criteria stated in text.

  1. Circle melody notes.
  2. Choose one substitute by function.
  3. Check each strong melody note against the new chord.

Help you can use: Step list · Single-variable revision

  • Melody remains clear.
  • Substitutions have named function.
  • Bass and phrase direction improve or change for a clear reason.
3 · Fade support

Use fewer prompts: melody-preserving reharmonization

Use fewer prompts stage for melody-preserving reharmonization, with instructions and success criteria stated in text.

  1. Use function labels without a chord menu.
  2. Revise bass motion for smoother direction.
  3. Remove substitutions that weaken the phrase.

Help you can use: Check after the attempt

  • Melody remains clear.
  • Substitutions have named function.
  • Bass and phrase direction improve or change for a clear reason.
4 · Independent attempt

Perform independently: melody-preserving reharmonization

Perform independently stage for melody-preserving reharmonization, with instructions and success criteria stated in text.

  1. Reharmonize an eight-bar melody with at least three techniques.
  2. Explain each substitution and melody fit.
  3. Perform original and reharmonized versions.

Help: Complete without prompts or a model.

  • Melody remains clear.
  • Substitutions have named function.
  • Bass and phrase direction improve or change for a clear reason.

Reflect

Explain each changed chord

For each replacement, name the original function, substitute function, melody note, bass motion, and reason the new route is stronger or different.

Guided practice

Build the skill in manageable steps

Exercise 1

One substitute at a time

Keep reharmonization audible and testable.

  1. Play the original phrase.
  2. Change one chord by function.
  3. Check the melody note.
  4. Compare before and after.
Success sounds or feels like
  • Only one chord changes.
  • Melody is accounted for.
  • The effect is described.
Make it smaller when
  • Use tonic-family substitution only.
Increase difficulty when
  • Use tritone substitution.
Exercise 2

Eight-bar alternate route

Create a complete reharm plan.

  1. Choose an eight-bar melody.
  2. Mark strong melody notes.
  3. Apply three substitution types.
  4. Perform original and reharmonized routes.
Success sounds or feels like
  • Three substitutions are labeled.
  • Strong melody notes fit or resolve.
  • The new route has coherent bass motion.
Make it smaller when
  • Use four bars.
Increase difficulty when
  • Add modal mixture and pedal point.

Common mistakes

Match the problem to a better next try

The new chord clashes with the melody by accident.

Likely cause: Melody notes were not checked.

Try: Circle strong melody notes before choosing substitutes.

Too many chords change and the phrase loses identity.

Likely cause: Novelty replaced direction.

Try: Change one structural point first and compare.

Knowledge check

Explain the practice decision

1. What must reharmonization account for first?
2. What does a tritone substitute usually replace?
3. Why label substitute function?

Check your work

Change the harmony without betraying the melody assessment

Complete every required criterion and record the requested reflection or value.

You check off guitar-playing tasks yourself. FretGarden only grades tasks where you tap, click, or choose an answer on screen.

Review plan

Return before the idea fades

Now

Reharmonize one chord and check the melody note.

Next session

Map three substitutions across an eight-bar phrase.

One week

Create a new alternate bass route for the same melody.

Long term

Treat melody and function as the contract for future reharmonization.

Optional extension: Write three reharmonizations of one cadence: diatonic, mixture, and tritone-substitute.