Terrarum Locus
MIDI Generator
Locus app icon

Locus

An AUv3 MIDI generator for iOS — a locked-loop mutator that creates evolving one-bar loops without losing their identity. Freeze a loop to build on it, or raise the variation and let it mutate while preserving its character.

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Quick Start

  1. Open your Audio Unit host (AUM, Drambo, Logic Pro).
  2. Add Locus as an AUv3 MIDI effect or MIDI generator.
  3. Route Locus MIDI output to a synth on another track.
  4. Choose an archetype and press Create.
  5. Adjust Variation to freeze or evolve the loop.
Note: Locus outputs MIDI only. It will not make sound until routed to a synth.

What Makes Locus Different

Frozen loops
Variation at 0 never changes — a stable foundation to build tracks on
Evolving loops
Variation above 0 mutates the loop gradually while preserving its identity
Deterministic
Same settings always produce the same output
RT-safe
Real-time-safe audio thread — zero glitches under load

The 13 Archetypes

Each archetype gives Locus a distinct musical personality to start from.

  • Puncture — sharp, accented pointillism
  • Groove — swung, feel-forward motion
  • Pulse — steady, driving repetition
  • Cascade — rolling, descending runs
  • Thump — weighty, low-centered hits
  • Cluster — dense, compact groupings
  • Chaos — unpredictable, scattered energy
  • Even Pulse — grid-aligned even spacing
  • Interlock — two-part hocketing patterns
  • Call/Answer — conversational phrasing
  • Arc — rising and falling shapes
  • Wander — meandering, free motion
  • Sparse Fractal — self-similar space

Usage Notes

Plugin type
MIDI only (no audio output)
Best hosts
AUM, Drambo, Logic Pro, GarageBand
Grid
One-bar motifs on a fixed 16-step grid
Transport
Syncs to the host clock at bar boundaries

Common Questions

  • No sound: Locus outputs MIDI only. Route it to a synth track.
  • The loop keeps changing: Lower the Variation. At 0 the loop is frozen and never changes.
  • It sounds different each time I load it: Same settings always produce the same output. Check that the archetype, seed, and variation match.
  • Changes feel delayed: Locus applies changes at bar boundaries for clean, glitch-free timing.