Pattern Design

Core Concepts

Pattern vs Order Table

Patterns: Unique musical content (A, B, C, D)
Order Table: Sequence of pattern playback

Order: [0, 1, 1, 2, 1, 1, 2, 3, 0]
       [A, B, B, C, B, B, C, D, A]  ← Song structure

Result: A plays once, B twice, C once, B twice again, etc.

Key insight: Reuse patterns via order table. Never duplicate pattern content.

Standard Lengths

Rows per beat: At speed 6, BPM 125: 4 rows = 1 beat, 16 rows = 1 bar

Song Structures

Loop-Based (Game Background Music)

Order: [0, 1, 1, 2, 1, 1, 2, 3]
        ↓  ↓←loop back←←←←↓

Pattern 0: Intro (plays once)
Pattern 1: Main A (verse)
Pattern 2: Main B (chorus/variation)
Pattern 3: Transition (leads back to 1)

Restart Position: 1 (skip intro on loop)

Linear (Cutscenes, Jingles)

Order: [0, 1, 2]  (End command at pattern 2's end)
No restart - one-shot playback

Pattern Budget

The 4-Pattern Song: Most simple tracks need only 4 patterns:

• Pattern 0: Intro
• Pattern 1: Verse/Main
• Pattern 2: Chorus/Variation
• Pattern 3: Bridge/Breakdown

Section Templates

Intro Pattern

Rows 0-15:  Sparse (drums only, or ambient pad)
Rows 16-31: Add bass
Rows 32-47: Add melody fragment
Rows 48-63: Build to full groove

Main/Verse Pattern

Rows 0-15:  Full groove established
Rows 16-31: Groove continues
Rows 32-47: Melodic content
Rows 48-63: Lead into next section

Chorus Pattern

Rows 0-15:  Impact! Full energy
Rows 16-31: Hook melody prominent
Rows 32-47: Hook develops
Rows 48-63: Prepare transition

Loop Point Design

Seamless Loop Requirements

1. Harmonic continuity - Last chord leads to first
2. Rhythmic continuity - Beat doesn't skip
3. Timbral continuity - Same instruments active
4. Dynamic continuity - Similar volume levels

Last 8 Rows Preparation

Row 56: Start volume fades (A08)
Row 58: Drum fill or transition start
Row 60: Clear held notes
Row 63: Clean state for loop

Setting Restart Position

module = XmModule(
    # ...
    restart_position=1,  # Skip pattern 0 (intro) on loop
)

64-Row Grid Reference

Rows    | Bar | Beat | Content
--------|-----|------|--------
0-15    | 1   | 1-4  | Phrase A
16-31   | 2   | 1-4  | Phrase A (variation)
32-47   | 3   | 1-4  | Phrase B
48-63   | 4   | 1-4  | Phrase B + transition

Drum Grid (4-on-floor)

Row | Beat | Kick | Snare | HH
----|------|------|-------|----
0   | 1.1  | X    |       | X
4   | 1.2  |      |       | X
8   | 1.3  |      | X     | X
12  | 1.4  |      |       | X
16  | 2.1  | X    |       | X
...

Anti-Patterns

Reference Files

• references/genre-templates.md - Complete templates for dance, ambient, boss battle, etc.
• references/loop-techniques.md - Advanced loop point techniques, fills, transitions