One aperture. Both carriers.
Each of the three plate assemblies is a complete dual-carrier instrument: a compression driver for sound and a flattened coaxial horn for radio-band light, sharing one Ø410 face. Sound and light leave through the same surface at wavelengths five orders of magnitude apart — the mesh that radiates sound reads as solid metal to the radio waves, and the slots that launch the light are far too sparse to block the sound. The physics is the diplexer; no diplexer part exists.
A compression driver, rebuilt as an instrument.
Three piezo elements sit at a common throat; phasing them against each other twists the sound as it leaves — chirality by drive, not by geometry. A torus doubles as the horn flare, its section fitted to the acoustic area law — never decreed. The horn feeds a density-graded ceramic gyroid: graded, because a uniform lattice is a filter and a graded one is a library, every frequency finding its own depth. The terminal layer opens straight into the face perforations.
A sunflower, machined.
The acoustic perforations are laid out on a golden-angle spiral — the same rule that packs sunflower seeds — so the pattern never repeats and its spectrum stays diffuse. Read the parastichies and you count 21 arms one way, 34 the other: consecutive Fibonacci numbers, not a choice. Equal counts would give a periodic lattice, and a periodic lattice is a filter with blind spots.
- Micro-horns, not holesEach perforation is cut with flared walls from both faces — a tiny biconical horn, acoustically matched, made by two spiral toolpaths.
- Slots, not tracesThe twelve spiral slots are voids in the conductor — a flattened coaxial horn that launches single-cycle electromagnetic pulses. Their geometry is defined by angles alone, so one printed face covers many octaves.
- Mirrored handednessFacing plates are mirror images with opposite intrinsic handedness — together they close the twist modes, and the pair can run as a coherent absorber for the dissolve mode.
- Aperiodic on purposeThe virtue is a diffuse spectrum, proven the hard way: we pre-registered the more exotic alternative against frozen criteria and retired it when it measured 12–16 dB worse. The sunflower earns its place by winning.
Two mirrored coils, never one.
Every winding in the machine is a pair of mirror-image coils on one torus, each with its own feed. That rule is informational, not aesthetic: with two independent circuits the same copper is a confined induction port, a fast pulse exciter, or anything in between — chosen per microsecond by drive, not by rewiring.
Sum mode
Drive both windings together and the flux stays confined in the ring — an induction port that levitates and heats conductive droplets in the bore column without touching anything.
Difference mode
Drive them against each other and the pair becomes a fast, low-inductance ring current — the exciter for the machine's single-cycle electromagnetic pulses.
Traveling wave
Three pairs stacked on one axis make six independent circuits — enough to synthesize a wave that travels along the bore and carries feedstock with it. The elevator is a field.
Every surface is a computed hologram.
The spiral slots, the sunflower field, the graded gyroid — none of these are shapes we chose. They are outputs of one procedure: solve for the surface that produces the field you want, then realise it in metal and ceramic. Half the boundary is printed and steers by frequency; the other half is driven and changes every microsecond. The plate pattern stops being a shape we choose and becomes a pattern we compute.
And because the design is specified in angles, ratios, winding numbers and grading laws — not millimetres — it renders on whatever the current generation of tooling can make. The milled plate is the optimum as pronounced by a milling machine; its job is to build the machine that pronounces it better.
The two carrier papers hold the element-level physics of the plate — horn, gyroid, face and windings on the acoustic side; slots, feeds and the optical stem on the electromagnetic side.