Population — A Persistent Unit of Voices

The shortest useful mental model of conchordal is not a note followed by another note. It is a population definition becoming a persistent population of living voices:

PopulationSpec + Placement --place()--> Population --> Voice(s)
                                                |
                                                `-- later generations

Community = every Population sharing the runtime terrain

A PopulationSpec is a reusable pre-placement definition. It combines the founder Voice defaults with policy that belongs to the population as a whole, such as lifecycle, viability, and respawn. A Placement says where and how many founder voices enter. place() combines them and immediately returns a Population: one stable handle for the placed population, not one handle per Voice. The runtime Community is the aggregate of all Populations that share the Landscape.

let population_spec = harmonic()
    .amp(0.035)
    .sustain()
    .respawn_capacity(6);

let population = place(
    population_spec,
    consonance(90.0, 900.0).count(6)
);
wait(3.0);
release(population);

Here population controls six founder Voices together. Reports distinguish their shared population_id from each individual voice_id. If a Voice dies and is replaced, its voice_id and generation change; the Population and its population_id do not.

The placement boundary

place() is the only transition from definition to runtime. Configure all initial-only properties on the PopulationSpec first. Once placed, a Population exposes only live patches and release; it cannot be turned back into a specification or have its founder policy rewritten.

let spec = harmonic()
    .brightness(0.4)
    .brain("entrain")
    .endurance(8.0);

let population = place(spec, consonance(220.0).count(3));
population.amp(0.03); // Live patch at the current script time.
flush();              // Emit pending live patches without advancing time.
wait(2.0);
release(population);

wait(seconds) also emits pending live patches, then advances the script cursor. Neither wait() nor flush() creates a deferred or draft Population: the founder Voices were scheduled by place() itself.

The API Reference marks PopulationSpec methods as initial-only and Population methods as live-patchable.

Five independent questions

A PopulationSpec answers several independent questions. Keeping them separate prevents one musical decision from being mistaken for another.

Question	Main controls	Meaning
What sounds?	`sine`, `harmonic`, `modal`, `brightness`, `modes`	The founder Voice body and spectrum.
What kind of life?	`brain(name)`: `entrain`, `seq`, `drone`	Whether articulation participates in ecology, follows an authored life, or persists as terrain.
When does it sound?	`sustain`, `repeat`, `metric`, `entrained`, `flow`	Phonation and onset timing.
Where does pitch go?	Placement, `anchor`, `seek_consonance`, `temperature`	Founder entry position and later movement.
How does the population persist?	`endurance`, `recovery`, viability, respawn	Voice energy, death, and Population turnover.

Calls on different rows compose. Calls on the same axis are generally last-write-wins; the API Reference identifies the exact builder behavior.

Articulation life: `brain`

brain(name) selects how a Voice lives while it is sounding:

brain("entrain") is the default living articulation. It can respond to consonance and rhythmic fit through the metabolism and lifecycle controls.
brain("seq") is an authored event with a fixed life. It ignores field viability and metabolism.
brain("drone") is undying until explicitly released. It is useful for terrain anchors and other persistent material.

This is separate from phonation timing. In particular:

brain("entrain") chooses a kind of life; .entrained() chooses medium coupling of repeated onsets to the shared meter.

The similar names describe different axes and may be used together.

let colony = harmonic()
    .brain("entrain")
    .entrained()
    .cycles(2)
    .seek_consonance()
    .endurance(8.0)
    .recovery(4.0)
    .consonance_viability(0.30, 0.80);

place(colony, consonance(90.0, 900.0).count(5));
wait(8.0);

The brain does not choose the body, Placement, or pitch strategy. A drone may be audible or habitat-only; a living Voice may be anchored or moving; the same modal body may use any articulation life.

Phonation and duration

Phonation answers two questions: when an onset occurs, and how long that onset remains open.

sustain() holds while the Voice is alive.
repeat() selects repeated phonation with defaults.
metric(), entrained(), and flow() select regions of the shared-meter coupling continuum and imply re-attacking behavior.
cycles(n) expresses duration in rhythmic cycles.

The lower-level once(), pulse(rate_hz), while_alive(), and adaptive duration controls are available when the presets do not express the intended gesture. Start with the presets; use explicit timing only when the piece needs it.

Release is not death

release(population) is a terminal script decision: later patches on that Population are ignored, its current Voices enter their release envelopes, and the Population closes. Ecological death is a runtime result: one living Voice exhausts its energy, after which the Population’s respawn policy may replace it. A section or play scope also releases the Populations it created when the scope ends.

The next chapter explains Voice and Landscape — Sound–Environment Feedback.

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