Music Theory Basics

Introduction to Music Theory for MIDI Composition

Understanding basic music theory isn't just for classical musicians—it's an essential toolkit for anyone creating music with MIDI and digital tools. This resource introduces fundamental concepts that will help you make more informed creative decisions and get the most out of MIDI Muse's AI-powered generation.

While MIDI Muse can generate compelling musical content even if you have no theoretical background, understanding these concepts will help you shape and refine generations more effectively, communicate your musical intentions more clearly, and create more sophisticated compositions.

The Building Blocks: Notes, Scales, and Keys

Notes and Pitches

Western music divides the octave into 12 equal parts, creating the 12 semitones we're familiar with: C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab, A, A#/Bb, and B. In MIDI, these are represented as numerical values from 0-127, with middle C (C4) being MIDI note 60.

Scales: The Palette of Notes

Scales are organized sequences of notes that form the foundation of melodies and harmonies. The most common scales include:

Beyond these basic scales, there are numerous other scales that create distinctive moods:

• Pentatonic Scales: Five-note scales that sound pleasant in almost any context
• Blues Scale: Adds a "blue note" to the minor pentatonic scale
• Modal Scales: Include Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian
• Harmonic Minor: Natural minor with a raised 7th degree
• Melodic Minor: Different ascending and descending patterns

Keys and Key Signatures

A key centers your music around a particular note (the tonic) and typically uses notes from a specific scale. For example, the key of C major uses notes from the C major scale, with C as the tonic.

The key signature is the set of sharps or flats that appear at the beginning of a piece to indicate its key. While MIDI doesn't visually display key signatures, understanding what key you're in helps ensure that generated content will sound harmonious.

Creating Harmony: Chords and Progressions

Chord Construction

Chords are three or more notes played simultaneously. The most basic chords are triads, which consist of three notes:

• Major Triad: Root, Major 3rd, Perfect 5th (e.g., C-E-G)
• Minor Triad: Root, Minor 3rd, Perfect 5th (e.g., C-Eb-G)
• Diminished Triad: Root, Minor 3rd, Diminished 5th (e.g., C-Eb-Gb)
• Augmented Triad: Root, Major 3rd, Augmented 5th (e.g., C-E-G#)

Extended chords add additional notes beyond the triad, creating richer harmonies:

• 7th Chords: Add a 7th above the root (e.g., Cmaj7 = C-E-G-B)
• 9th Chords: Add a 9th above the root (e.g., Cmaj9 = C-E-G-B-D)
• 11th and 13th Chords: Add even more extensions for jazz and complex harmonies

Chord Progressions

Chord progressions are sequences of chords that provide the harmonic foundation of a piece. In any key, chords are built on each degree of the scale and are often referred to by Roman numerals:

Some of the most common chord progressions in popular music include:

• I-IV-V: The foundation of blues and rock (C-F-G in C major)
• I-V-vi-IV: The "pop-punk progression" used in countless hits (C-G-Am-F in C major)
• ii-V-I: The quintessential jazz progression (Dm7-G7-Cmaj7 in C major)
• vi-IV-I-V: The "sensitive singer-songwriter" progression (Am-F-C-G in C major)

Creating Movement: Rhythm and Time

Time Signatures

Time signatures define how beats are grouped in a measure. The top number indicates how many beats per measure, while the bottom number shows what note value gets one beat:

• 4/4: Four quarter-note beats per measure (most common in popular music)
• 3/4: Three quarter-note beats per measure (waltz time)
• 6/8: Six eighth-note beats per measure, often felt as two groups of three
• Odd time signatures: 5/4, 7/8, etc., create interesting rhythmic patterns

Rhythm Values

Notes can have different durations, creating rhythmic variety:

• Whole notes: Last for 4 beats in 4/4 time
• Half notes: Last for 2 beats
• Quarter notes: Last for 1 beat
• Eighth notes: Last for 1/2 beat
• Sixteenth notes: Last for 1/4 beat
• Triplets: Divide a beat into 3 equal parts instead of 2
• Dotted notes: Extend a note's duration by 50%

In MIDI, note durations are specified precisely, making it easy to create complex rhythmic patterns that would be challenging to perform live.

Bringing It All Together: Melody and Structure

Melody Writing

Effective melodies often combine these elements:

• Contour: The overall shape (rising, falling, arching)
• Motifs: Short, memorable patterns that can be repeated and varied
• Tension and Release: Moving away from and back to stable notes
• Question and Answer: Phrases that feel like they respond to each other
• Scale-based vs. Chromatic: Using notes from the scale vs. adding outside notes

To learn more about creating effective melodies with MIDI Muse, see our detailed guide on Creating Complex Melodies.

Song Structure

Most popular music follows recognizable structures:

• Intro: Sets the mood and introduces musical elements
• Verse: Presents the main narrative, often with the same music but different lyrics
• Chorus: The catchiest, most memorable section that often contains the main message
• Bridge: Provides contrast and a break from the verse-chorus pattern
• Outro/Coda: Brings the piece to a conclusion

Common structures include Verse-Chorus-Verse-Chorus-Bridge-Chorus (ABABCB) and Verse-Chorus-Verse-Chorus-Bridge-Chorus-Outro (ABABCBO).

Practical Application in MIDI Muse

Setting Parameters Based on Theory

Understanding music theory helps you make informed choices when setting MIDI Muse parameters:

Analyzing and Editing MIDI Muse Output

After generating MIDI content, you can apply your theoretical knowledge to analyze and refine it:

1. Identify the key centers to understand where the music is stable vs. creating tension
2. Look for accidental notes that might be outside the scale—decide if they create pleasing color or need correction
3. Analyze the chord progression to see if it follows functional harmony or creates interesting deviations
4. Examine rhythm patterns for consistency and variety
5. Check melodic contour to ensure it has a pleasing shape with appropriate climaxes

Conclusion

Music theory isn't a set of rigid rules but rather a framework for understanding how music works. With MIDI Muse, you can apply theoretical concepts to guide the AI generation process, then use your musical intuition to decide what works best for your creative vision.

As you gain more theoretical knowledge, you'll find that you can communicate more precisely with MIDI Muse's generation parameters, resulting in compositions that more closely match your creative intentions.

Remember that great music often comes from understanding the rules well enough to know when and how to break them. MIDI Muse gives you the tools to explore both conventional and experimental approaches to composition, all informed by your growing understanding of music theory.

To apply these concepts in practice, explore our other Academy resources, particularly our guides on Creating Complex Melodies and Multi-Context MIDI Generation.