Add Rhythm

In this tutorial, you'll learn to work with timing and duration to create rhythmic patterns.

Objective

Create a simple rhythmic melody using different note lengths.

Prerequisites

• Completed Build a Major Scale
• Understanding of beat-based timing

Understanding Time in RMT

Time in RMT Compose is based on:

Property	Description	Unit
tempo	Beats per minute	BPM
startTime	When a note begins	Seconds
duration	How long a note plays	Seconds

Beat Duration Formula

// Duration of one beat in seconds
beatDuration = 60 / tempo

// In RMT expression:
new Fraction(60).div(module.findTempo(module.baseNote))

At 120 BPM: 60/120 = 0.5 seconds per beat

Note Duration Reference

Note	Beats	Expression
Whole	4	beatDuration.mul(new Fraction(4))
Half	2	beatDuration.mul(new Fraction(2))
Quarter	1	beatDuration
Eighth	0.5	beatDuration.mul(new Fraction(1, 2))
Sixteenth	0.25	beatDuration.mul(new Fraction(1, 4))
Dotted quarter	1.5	beatDuration.mul(new Fraction(3, 2))
Triplet	1/3	beatDuration.mul(new Fraction(1, 3))

Step 1: Set Up

1. Reset to a fresh workspace
2. Set BaseNote tempo to 120 BPM:

new Fraction(120)

Step 2: Create the Beat Duration Helper

First, understand the beat duration expression:

// This expression equals one beat duration
new Fraction(60).div(module.findTempo(module.baseNote))

We'll use this as the base for all durations.

Step 3: Create a Rhythmic Pattern

Let's create: Quarter - Eighth - Eighth - Half

Note 1: Quarter Note

1. Add a note
2. Frequency: module.baseNote.getVariable('frequency') (root)
3. StartTime: new Fraction(0)
4. Duration (1 beat):

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

Note 2: First Eighth Note

1. Add note after Note 1
2. Frequency: baseNote × 9/8 (Re)
3. StartTime: note1.startTime + note1.duration
4. Duration (0.5 beats):

new Fraction(60).div(module.findTempo(module.baseNote)).mul(new Fraction(1, 2))

Note 3: Second Eighth Note

1. Add note after Note 2
2. Frequency: baseNote × 5/4 (Mi)
3. StartTime: note2.startTime + note2.duration
4. Duration (0.5 beats):

new Fraction(60).div(module.findTempo(module.baseNote)).mul(new Fraction(1, 2))

Note 4: Half Note

1. Add note after Note 3
2. Frequency: baseNote × 3/2 (Sol)
3. StartTime: note3.startTime + note3.duration
4. Duration (2 beats):

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

Verification

1. Click Play
2. You should hear: short - quick quick - looong
3. Total duration: 1 + 0.5 + 0.5 + 2 = 4 beats (one measure at 4/4)

Visual Check

In the workspace:

• Note 1 is medium width
• Notes 2 and 3 are half as wide
• Note 4 is twice as wide as Note 1

Using Duration Quick Controls

Instead of typing expressions, use the Variable Widget shortcuts:

1. Select a note

2. Find the duration row

3. Click the note-length icons:

   • 𝅝 = Whole note
   • 𝅗𝅥 = Half note
   • ♩ = Quarter note
   • ♪ = Eighth note
   • 𝅘𝅥𝅯 = Sixteenth note

4. Add dots for dotted notes (1.5× or 1.75× duration)

Exercises

Exercise 1: Different Tempo

1. Change BaseNote tempo to new Fraction(60) (60 BPM)
2. Play - the rhythm is the same but slower!
3. The relationships are preserved

Exercise 2: Syncopation

Create an off-beat accent:

1. Make Note 2 start half a beat late
2. Make Note 1 duration 1.5 beats
3. Overlap creates syncopation

Exercise 3: Triplets

Create triplet rhythm (3 notes in the space of 2):

// Triplet duration (1/3 of a beat)
new Fraction(60).div(module.findTempo(module.baseNote)).mul(new Fraction(1, 3))

Exercise 4: Rest Simulation

Create the effect of a rest:

1. Make a note's duration shorter than the gap before the next note
2. Or: create a silent note (set a very low frequency that won't be heard)

Chaining Rhythms

For complex rhythms, use note references:

// Note 5 starts when Note 4 ends
module.getNoteById(4).getVariable('startTime')
  .add(module.getNoteById(4).getVariable('duration'))

This creates a chain where timing flows automatically.

Save Your Module

1. Menu > Save Module
2. Name it rhythmic-pattern.json

What You Learned

• How tempo, startTime, and duration relate
• Creating different note lengths
• Chaining notes for sequential rhythm
• Using quick controls for duration

Next Steps

• Note Dependencies - Create smarter timing chains
• Working with Measures - Add measure structure
• Combine rhythm with chords for fuller arrangements