← 0

Fig. 1: Signal Path

sonic.org.uk · the published schematic

0 · signal path MIC 1 ANALYSER f0 · envelope RESONATOR BANK 2 · eight 2-pole TPT filters, Q 18–240 0102 0304 0506 0708* ⋮ COUPLING 8×8, rows Σ=1 3 SPACE ENGINE diffuse → 8× FDN Householder reflect 8 primes, 20–120ms shimmer + grains RT60 0.1–240s 4 SHAPER 4× oversampled MERGER ch 1–8 dry ch 9 shaped 5 virtual device → DAW
No energy is generated anywhere in this diagram. It is moved, delayed, and lost. That is the whole of the idea and the whole of the honesty.
1
Microphone, analysed only: never recorded, never routed to any output.
2
Eight resonators, four hard-wired pairs (dashed). Resonator 08 (*) drifts towards the room's estimated fundamental.
3
Coupling matrix: energy redistributed between resonators, never amplified (rows sum to exactly 1.0).
4
Space engine: Dattorro-style diffusion, then eight prime-length delay lines mixed through a Householder reflection (Fig. 2), scaled and timed together by FORM. An octave-up shimmer voice and grains harvested from the delay memory feed back into the same loop, both derived from the current ratio set, never a separate generator.
5
Nine channels out: 1–8 dry, 9 the shaped sum. Not the same signal twice.

Engine

Sample rate
48,000 Hz
Quantum
128 frames (2.7 ms)
Channels out
9
Oversampling
4× (shaper only)

Resonator

Topology
TPT state-variable (Zavalishin)
Q range
18 – 240 (up to 240 × 2.2 at rest, settling ii)
Fundamental range
22 – 880 Hz, untempered
Space engine lines
8, prime-length, 20 – 120 ms
Space engine RT60
0.1 – 240 s

Constraints

Coupling/space feedback gain
0.003, the least this project could stay stable at
Matrix smoothing
40 ms
Reflection orthogonality
HᵀH = I to 1e-12, asserted at build and in dev
Coupling row sums
1.0 ± 1e-6
Bundle, gzipped
under 200 kB, fonts excluded
Offline
yes, after first load

No energy is generated anywhere in this diagram. It is moved, delayed, and lost. That is the whole of the idea and the whole of the honesty.

Fig. 2: Geometry

The five ratio sets HARMONIC sweeps, and where the octagram's numbers come from

AtSetRatios
0.00Unison1 · 1 · 1 · 1 · 1 · 1 · 1 · 1
0.25Tetractys1 · 2 · 3 · 4 · 6 · 8 · 9 · 12
0.50Octagram1 · 1.8478 · 2 · 2.4142 · 2.6131 · 3.6955 · 4.8284 · 5.2262
0.75Vesica1 · 1.7321 · 2 · 3.4641 · 4 · 6.9282 · 8 · 13.8564
1.00Phi1 · 1.2720 · 1.6180 · 2.0582 · 2.6180 · 3.3302 · 4.2361 · 5.3884
HARMONIC interpolates continuously between these five anchors in the logarithmic domain. Resonator n sits at f0 · ratio[n]. Nothing snaps and nothing is labelled on the dial.
0 · the octagram 1 2 3 4 5 6 7 8
The octagon's eight vertices (brass) and its four distinct chord lengths (arc, one opacity per step size): 2R·sin(kπ/8) for k = 1…4, plus their octaves. The interface was always a ratio table; on the ring itself (§8), these same chords light up in arc as HARMONIC sweeps through 0.5.