Perceptual Interfaces — Haptic, Tactile & Whole-Body Listening Surfaces

If loudspeakers put sound “over there,” perceptual interfaces put it “through here.” The division’s lineage begins with motorized resistance in microtonal keyboards — keys that re-weight as tuning shifts — and extends to a 128-point somatosensory floor array on which low-frequency content is rendered as standing-wave pressure underfoot.

Technical work centers on closed-loop haptics with sub-millisecond latency, capacitive polyphonic pressure sensing, and psychoacoustic validation. The 128-floor was evaluated with whole-body categorical perception studies; results showed listeners can localize narrowband content via plantar vibration with accuracy comparable to interaural time differences below 80 Hz. The microtonal surface couples just-noticeable-difference pitch metrics to motor torque, so a performer feels when they are between tunings.

Published interfaces are accompanied by task-based evaluations, hazard notes where actuators can pinch or overheat, and browser proxies where haptics are simulated via audio-reactive visuals in SPECTRA//LAB.

Haptic evaluation couples psychophysics to bench spec. The 128-point floor was tested with a two-alternative forced-choice task: listeners standing on the array localized narrowband 40 Hz content via plantar vibration alone, with mean error 18° vs 14° via audition — near parity in the band where audition degrades. Thresholds, confusion matrices and trial-level data are summarized in the monograph and linked to the prototype dossier’s bill of materials (e.g., solenoid part Bourns 3852A, tolerance ±10%). The microtonal keyboard’s torque map was co-designed with JND pitch data so that a performer feels, not just hears, when they cross a 12-cent boundary.

Instrumentation is openly specified so replication is possible without ZIAA hardware. Capacitive pressure is read at 1 kHz via Teensy 4.1, fused with WASM gesture tracking, and logged as research notes with telemetry (splDecibels, magneticFlux, spectralCoherence). Browser proxies do not pretend to be haptics; SPECTRA//LAB renders floor zones as audiovisual fields with pointer interpolation, so the mapping logic is testable without the floor. Hazard notes — pinch torque 2.1 Nm, thermal limit 68 °C — are published alongside, not hidden.