Day 29: 32-Bar Form and Chords in GarageBand
Thursday, April 30th, 2026
Objectives
- I can import a MIDI chord progression into GarageBand and assign it an instrument sound.
- I can arrange chord regions into AABA (32-bar) form in the GarageBand timeline.
- I can add a drum loop and begin writing a melody using Musical Typing or a MIDI keyboard.
- I can use the arpeggiator to transform chords into a moving melodic pattern.
Warmup — Download and Import MIDI Files
Step 1: Download the chord progressions ZIP archive.
Step 2: Unzip the file. You will find folders of MIDI files organized by key and mood. Browse the file names — each one tells you the chord progression and a mood description (for example, C – I V vi IV – Hopeful Romantic or A – i VI III VII – Nostalgic Hopeful).
Step 3: Pick one chord progression you like the sound of.
Step 4: Import your chosen MIDI file into GarageBand.
- Open a new GarageBand project.
- Drag the MIDI file from Finder directly into the GarageBand timeline. GarageBand will create a new Software Instrument track automatically.
- Double-click the region to open the Piano Roll and look at the chord notes inside. You should see groups of notes stacked vertically — those are your chords.
Step 5: Click the track instrument name (it might say “Steinway Grand Piano”) and try a few different sounds. Pick something you like — piano, strings, or an electric keyboard all work well.
Work Session
Key Vocabulary
- AABA form (32-bar form)
- A four-section structure used in thousands of jazz standards and pop songs. The A section states the main musical idea, B (called the “bridge”) provides contrast, and the final A brings back the main idea. With 8 measures per section, the full form is 32 measures: A (8) + A (8) + B (8) + A (8).
- MIDI
- Musical Instrument Digital Interface. MIDI files do not contain audio — they contain note data (which notes, how long, how loud). That is why you can change the instrument sound after importing without re-recording anything.
- Arpeggiator
- An effect that automatically plays the notes of a chord one at a time in a repeating pattern instead of all at once. The result is a moving, melodic texture built from the chord.
- Musical Typing
- A GarageBand feature that turns your computer keyboard into a MIDI keyboard so you can play notes without a physical controller. Press Command + K to open it.
Part 1 — Build the AABA Form
Each MIDI file you downloaded is already a complete chord progression — it has all its chords and is ready to use as-is. Your job is to arrange it into AABA form by duplicating and placing the region in the timeline.
AABA form has four sections. Each section should be 8 measures long. If your chord progression is shorter than 8 measures, loop it to fill the full 8 measures — Option-drag copies of it end-to-end until the section reaches measure 8. For example, a 2-measure progression would be repeated 4 times to make one 8-measure A section.
| Section | Role |
|---|---|
| A | Main idea — your chosen chord progression |
| A | Repeat of the main idea |
| B | Contrasting section (the “bridge”) |
| A | Return of the main idea |
Step 1 — Duplicate your A section region
Your imported MIDI region is your first A section. First, if needed, Option-drag copies of it end-to-end to fill 8 measures. Then Option-drag the complete 8-measure A section two more times so your timeline reads: A (mm. 1–8) – A (mm. 9–16) – [gap mm. 17–24] – A (mm. 25–32).
Leave an 8-measure gap between the second A and the third A — that gap is where the B section will go.
Step 2 — Create the B section
The B section should contrast with the A sections. Try one of these approaches:
| Option | How to do it |
|---|---|
| Different MIDI file | Import a second chord progression with a different mood and drag it into the gap. |
| Same chords, different sound | Option-drag your A region into the gap, then change the instrument sound to something that sounds clearly different — strings vs. piano, for example. |
| Same region, different octave | Option-drag your A region into the gap, open the Piano Roll (double-click), select all notes (Command + A), and press Shift + Command + Up Arrow to move them up an octave. |
Pick whichever option sounds best to you.
Step 3 — Add a drum loop
- Open the Loop Browser (press O or click the loop icon in the top-right corner).
- Search for a genre or style that fits your chord progression’s mood.
- Drag a drum loop into the timeline — GarageBand will create a new track automatically.
- Extend the drum loop to cover the full length of your project by dragging its right edge to the right.
Part 2 — Explore the Arpeggiator
The arpeggiator takes your chord notes and plays them one at a time in a pattern. It can make a simple chord progression sound much more interesting.
Step 1 — Open the arpeggiator
- Click on your chord instrument track to select it.
- Click the Smart Controls button at the bottom of the screen (the button that looks like a row of knobs), or press B.
- In the top-right corner of the Smart Controls area, look for the Arpeggiator button — it looks like a staircase icon. Click it to turn it on.
Step 2 — Try different settings
| Setting | What it does |
|---|---|
| Rate | How fast the arpeggio moves — try 1/8 or 1/16 for a busy, rhythmic feel. |
| Order | The direction: Up, Down, Up/Down, or Random. |
| Octave Range | How many octaves the pattern spans. Try 1 or 2. |
Press Space to play back and experiment.
Step 3 — Decide whether to keep it
If the arpeggiator makes your track sound more interesting, leave it on. If it sounds too busy or clashes with something else you plan to add, turn it off. Either choice is fine.
Part 3 — Begin Your Melody
Start a melody on top of your chord progression today. You will have all of Friday (Day 30) to finish and refine it — the goal right now is to get something started. You have two options for how to record.
Option A — Musical Typing (computer keyboard)
- Press Command + K to open Musical Typing.
- Create a new Software Instrument track (click the + button at the top of the track list).
- Choose an instrument that sounds different from your chord track — a flute, synth lead, or vibraphone can work well for a melody.
- Make sure the record head (the playhead) is at measure 1.
- Press R to begin recording. Play a few notes using the keyboard.
The keyboard layout:
- The A, S, D, F, G, H, J row plays white keys starting from C.
- The W, E, T, Y, U row plays the black keys (sharps/flats).
Option B — MIDI Keyboard
If you have a MIDI keyboard at your station, plug it in. GarageBand should detect it automatically. Create a new track, select an instrument, press R, and play.
Melody Guidelines
- If your chord progression is major (C major): Use notes from the C major scale — C D E F G A B C. Start and end your melody on C.
- If your chord progression is minor (A minor): Use notes from the A natural minor scale — A B C D E F G A. Start and end on A.
- If your chord progression is in a different key: Your scale uses the same pattern, just starting on your root note. For example, G major is G A B C D E F# G, and D minor is D E F G A B♭ C D. If you are unsure which scale fits your key, ask Mr. Willingham.
- Your melody should follow the AABA form of your chords — but you can simplify it. Even a 4-measure melodic idea repeated in the right places is enough.
- Use the Piano Roll to clean up any notes that did not record the way you intended.
- You do not need a complete melody today. Getting the first A section started is enough — you will finish on Day 30.
Checkpoint: Work Session
- I have four sections in the timeline — A (mm. 1–8), A (mm. 9–16), B (mm. 17–24), A (mm. 25–32).
- My B section sounds different from my A sections in at least one way.
- I added a drum loop that covers the full length of my project.
- I tried the arpeggiator and decided whether to keep it on or off.
- I started recording or drawing in melody notes on a new track.
- I saved my GarageBand project.
Closing
Play your project from beginning to end and listen for these three things before you save:
- Does the B section sound clearly different from the A sections? If they all sound identical, pick one thing to change in the B section — the instrument, the octave, or the chord file.
- Does the melody (even if incomplete) feel like it belongs over the chords? If a note sounds like it clashes, open the Piano Roll and move it up or down by one step until it fits.
- Is the overall volume balanced? If the drums are drowning out everything else, click the drum track and pull the volume slider to the left.
When you are done listening, save your GarageBand project — you will open it again on Friday to finish and submit.
Standards
- MSMTC8.CR.1 — Generate musical ideas for various purposes and contexts (importing MIDI chord progressions and adding original drums and melody in GarageBand).
- MSMTC8.CR.2 — Select and develop musical ideas for defined purposes and contexts (selecting a chord progression by mood and arranging it into AABA form with a contrasting B section).
- MSMTC8.CR.3 — Evaluate and refine selected musical ideas to create musical work that meets appropriate criteria (using playback to identify and fix clashing melody notes, balance issues, and weak B-section contrast before submitting).
- MSMTC8.CR.4 — Share creative musical work that conveys intent, demonstrates craftsmanship, and exhibits originality (saving a GarageBand project with chords, drums, and a melody-in-progress arranged in AABA form, to be finished and submitted on Day 30).