Build a Major Scale

In this tutorial, you'll build a major scale using just intonation ratios - the exact fractions from the natural harmonic series.

Objective

Create an 8-note major scale (Do-Re-Mi-Fa-Sol-La-Ti-Do) using pure ratios.

Prerequisites

• RMT Compose running
• Familiarity with the Variable Widget
• Understanding of Core Concepts

The Major Scale Ratios

Degree	Name	Ratio	Decimal
1	Do	1/1	1.000
2	Re	9/8	1.125
3	Mi	5/4	1.250
4	Fa	4/3	1.333
5	Sol	3/2	1.500
6	La	5/3	1.667
7	Ti	15/8	1.875
8	Do	2/1	2.000

Step 1: Set Up the BaseNote

1. Open RMT Compose
2. Click the BaseNote (orange circle)
3. In the Variable Widget, scroll down to the bottom and click "Clean Slate" to remove all notes except the BaseNote
4. Verify the BaseNote settings are what you want:
   • frequency: e.g. 440 (A4)
   • tempo: e.g. 120 (120 BPM)

Step 2: Create the Root (Do)

1. With the BaseNote selected
2. In the Variable Widget, find "Add Note / Silence" section
3. Select "Note", then click "Create Note"
4. Select the new note
5. Set its frequency:

base.f

Legacy JavaScript syntax

module.baseNote.getVariable('frequency')

6. Set its duration to a quarter note:

beat(base)

Legacy JavaScript syntax

new Fraction(60).div(module.findTempo(module.baseNote))

7. Click Save

Step 3: Create Re (9/8)

1. Select the Do note you just created (Note 1)
2. In "Add Note / Silence", keep "Note" and "At End" selected, click "Create Note"
3. Select the new note (Note 2)
4. Set its frequency:

base.f * (9/8)

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(9, 8))

5. Click Save

Step 4: Create Mi (5/4)

1. Select Note 2
2. Click "Create Note" (in "Add Note / Silence" section)
3. Select Note 3
4. Set its frequency:

base.f * (5/4)

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(5, 4))

5. Click Save

Step 5: Create Fa (4/3)

1. Select Note 3
2. Add a new note
3. Set frequency:

base.f * (4/3)

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(4, 3))

Step 6: Create Sol (3/2)

1. Add note after Fa
2. Set frequency:

base.f * (3/2)

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(3, 2))

Step 7: Create La (5/3)

1. Add note after Sol
2. Set frequency:

base.f * (5/3)

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(5, 3))

Step 8: Create Ti (15/8)

1. Add note after La
2. Set frequency:

base.f * (15/8)

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(15, 8))

Step 9: Create High Do (2/1)

1. Add note after Ti
2. Set frequency:

base.f * 2

Legacy JavaScript syntax

module.baseNote.getVariable('frequency').mul(new Fraction(2))

Verification

1. Click Play to hear your scale
2. You should hear 8 notes ascending
3. The last note (high Do) should sound like the first note, but higher

Check Your Work

Select each note and verify the frequency ratio in the Variable Widget:

Note ID	Expected Ratio
1	1/1
2	9/8
3	5/4
4	4/3
5	3/2
6	5/3
7	15/8
8	2/1

Save Your Module

1. Click Menu > Save Module
2. Rename to major-scale-just.json

Exercises

Exercise 1: Descending Scale

Modify your scale to descend from high Do to low Do.

Hint: Change the order of start times, or create new notes in reverse order.

Exercise 2: Change the Root

1. Click the BaseNote
2. Change frequency to 330 (E4)
3. Play - the scale is now in E major!

Exercise 3: Longer Notes

Change all durations to half notes:

beat(base) * 2

Legacy JavaScript syntax

new Fraction(60).div(module.findTempo(module.baseNote)).mul(new Fraction(2))

What You Learned

• Major scale intervals as pure ratios
• Creating sequential notes using "At End" positioning
• How changing BaseNote transposes the entire scale
• The relationship between tempo and duration

Next Steps

• Create a Major Triad - Build a chord
• Add Rhythm - Create varied rhythms
• Compare with 12-TET to hear the difference