2.9 Pattern & sound atlas: parameter → pattern → sound → feeling
To learn which setting creates which pattern and which feeling, the atlas plays the instrument through a grid of settings: separation, alignment and cohesion each at 25 / 75 / 125 / 175 (the centres of 0–50, 50–100, 100–150, 150–200) — 64 settings, each settled for 20 s and measured for 20 s with two seeds, plus a 10 s video clip and a still of each. The beat layer stays off and is not in the clips: the radii don't decide the beat (speed, max force and the grid do), so the beat has its own atlas (2.10).
- Pattern: flocks, largest flock's share, share of boids in flocks, order inside flocks, flock births per second.
- Sound: loudness, notes per second, drone pitch, harmonicity, brightness, pitch movement.
- Feeling, after a common model of music psychology: energy (arousal) = loudness, note density, movement, brightness; mood (valence) = consonance and register. Both are ranked against the other settings, so the words mean “compared to the rest of this instrument”. The model mostly follows harmony, so these automatic words are a first guess, refined by listening.
Separation 0–50 · 50–100 · 100–150 · 150–200
Separation 0–50
Alignment ↓
Cohesion →
Cohesion →
0–50
50–100
100–150
150–200
Alignment 0–50
Alignment 50–100
Alignment 100–150
Alignment 150–200
Separation 50–100
Alignment ↓
Cohesion →
Cohesion →
0–50
50–100
100–150
150–200
Alignment 0–50
Alignment 50–100
Alignment 100–150
Alignment 150–200
Separation 100–150
Alignment ↓
Cohesion →
Cohesion →
0–50
50–100
100–150
150–200
Alignment 0–50
Alignment 50–100
Alignment 100–150
Alignment 150–200
Separation 150–200
Alignment ↓
Cohesion →
Cohesion →
0–50
50–100
100–150
150–200
Alignment 0–50
Alignment 50–100
Alignment 100–150
Alignment 150–200
2.9.1 Each parameter on its own
One parameter at one range, averaged over all settings of the other two (computed from atlas.csv):
| Parameter | Range | Flocks | Largest | Loudness dB | Notes/s | Harmonicity |
|---|---|---|---|---|---|---|
| separation | 0 – 50 | 2.5 | 74% | -17.7 | 9.2 | 0.99 |
| 50 – 100 | 2.5 | 70% | -19.9 | 11.9 | 0.84 | |
| 100 – 150 | 1.4 | 69% | -21.3 | 15.7 | 0.83 | |
| 150 – 200 | 2.0 | 57% | -23.3 | 13.7 | 0.74 | |
| alignment | 0 – 50 | 3.1 | 39% | -26.5 | 19.8 | 0.48 |
| 50 – 100 | 1.9 | 57% | -22.6 | 17.3 | 0.84 | |
| 100 – 150 | 2.2 | 79% | -17.4 | 8.2 | 0.99 | |
| 150 – 200 | 1.2 | 95% | -15.7 | 5.3 | 0.99 | |
| cohesion | 0 – 50 | 1.9 | 47% | -25.3 | 9.7 | 0.99 |
| 50 – 100 | 2.4 | 55% | -22.5 | 11.7 | 0.92 | |
| 100 – 150 | 2.7 | 76% | -18.1 | 14.5 | 0.79 | |
| 150 – 200 | 1.5 | 92% | -16.2 | 14.7 | 0.77 |
2.9.2 What each parameter does
| Parameter | Role | Low → high |
|---|---|---|
| alignment | harmony — the strongest mood control | bell-like and quiet → one big ordered flock, a clean chord, loud |
| cohesion | gathering: how many voices | with low alignment, 75–125 splits the swarm into many small flocks (up to 12) = 4 voices at once; high pulls everything into one mass |
| separation | encounter notes and spacing | the larger the radius, the more boids meet at its edge: about 9 notes/s at 0–50, 14 – 16 at 100–200. At 150–200 the stage gets crowded (about 131 px per boid), the swarm jams and trembles, and the trembling crackles (2.4.3) |
Interactions matter: cohesion 175 gives a bright chord with high alignment, but a dissonant mass with low alignment. The per-parameter table is a rough guide; the 64-setting table in the atlas is the real map.
2.9.3 Seven sound recipes
| Recipe | sep / ali / coh | Pattern | Sound |
|---|---|---|---|
| 1 · Crackle | 150–200 / ≤ 75 / ≤ 75 | jammed, trembling in place | a quiet crackle with scattered notes (about −40 to −33 dB) |
| 2 · Rain | 25–75 / 25 / 25 | scattered | only encounter notes, 20–24/s, no drone, quiet |
| 3 · Bell polyphony | 25 / 25 / 75–125 | ~10 – 12 small flocks | 4 bell-like voices + dense rain, lively |
| 4 · Still chord | 25–125 / 125–175 / 25 | one aligned flock | pure consonant chord, almost no notes |
| 5 · Full chord + rain | 25 / 125–175 / 125–175 | one big flock | loudest, consonant, dense notes: climax |
| 6 · Turbulence | 175 / 125 / 25–75 | flocks form and break (~4/s) | voices jump in pitch: nervous, unstable |
| 7 · Dissonant mass | 125–175 / 25–75 / 175 | spread out, yet one flock | one loud, bell-like, unresolved drone |
My own example, 25–50–90 (“many small flocks, vivid, dynamic, high tone”), falls in recipe 3: the measurements agree with the ear.
2.9.4 In the club edition
The club edition (2.5) arranges the same swarm differently, so the atlas was played once more in it: the same 64 settings and seeds — the flights are the same, since the club never touches the flock — heard at 110 bpm, with the beat, the drones and the notes at their middle volume. Under each still in the atlas, a second line says what the club plays most of the time, and its own play button plays it: ten seconds of the same flight as the clip.
| What the club plays most of the time | Settings | Beat flights |
|---|---|---|
| the drop: four, blip, bass | 41 | 11 |
| pulse | 11 | 0 |
| half time + bass | 4 | 0 |
| four to the floor + bass | 2 | 0 |
| jam beat | 2 | 0 |
| four to the floor + blip | 2 | 0 |
| pulse, beat at times | 1 | 0 |
| four to the floor | 0 | 1 |
| half time | 1 | 0 |
The club's arrangement is coarse. Wherever one flock holds a quarter of the boids or more, the club plays the drop — four to the floor, the blip and the bass — and the radii make such a flock in most settings. The quieter parts live at the edges of the map: scattered boids at low alignment and cohesion leave only the pulse (a breakdown), loose swarms play half time with the bass, and the jam at the largest separation keeps the beat without a flock. So in the club edition the radii mostly choose between breakdown and drop; what lies between comes from the flight, the tempo and the volumes.