Two patent-pending inventions that passively attenuate HVAC duct-propagated noise across 200–900 Hz — without powered equipment, plenum boxes, or duct modification.
App. No. 64/072,212 · VOXN-001-PROV · VOXN-002-PROV · Priority May 22, 2026
Voxnil™ covers the entire acoustic register attenuation space through two independently licensable, patent-anchored systems — each manufacturable via standard injection molding.
Co-formed resonator insert seated in the register throat. Helmholtz unit cells and tortuous-path channels attenuate duct-propagated airborne sound without duct modification or powered equipment.
The register faceplate itself is the attenuator. Co-formed labyrinthine resonator geometry within the plate body provides passive broadband attenuation — no protruding structures, no power, no plenum box.
Require duct modification, reduce airflow below code minimums, and address a downstream segment rather than the terminal register where duct noise re-radiates into occupied space.
Add cost, volume, and above-ceiling labor; cannot be field-retrofitted without significant ductwork reconfiguration. Overkill for the 200–900 Hz range that drives occupant complaints.
Requires power, microphones, and continuous calibration. Prohibitively expensive per register and vulnerable to signal drift. No commercially viable ANC register grille exists at scale.
Fibrous liner addresses mid-to-high frequencies in long runs; provides negligible benefit at the throat where standing-wave re-radiation into room occurs. Also requires re-lining entire duct system.
The Voxnil Insert is a single-piece injection-molded component that drops into any standard ANSI register throat. Arrays of Helmholtz unit cells — cavities connected to the airflow channel by calibrated necks — are tuned to resonate at the target frequencies (200–900 Hz), destructively interfering with incoming sound energy.
Tortuous-path channels add viscous dissipation, boosting broadband attenuation between resonance peaks. The geometry is co-formed: no adhesives, no separate components, no field assembly. Open area ≥60% ensures airflow retention ≥75% per ANSI/ACCA MJ-8.
Co-formed metamaterial insert for register throat; labyrinthine resonator geometry within insert body; passive attenuation of duct-propagated airborne sound 200–900 Hz; ANSI/ACCA MJ-8 compatible; no powered equipment.
Helmholtz unit cells with D/T_b ∈ [0.10, 0.90] and W/H_r ∈ [0.05, 0.25]; multi-frequency tuning with |f_r1−f_r2| ≥ 100 Hz; tortuous-path L_p ≥ 3×T_b; membrane-backed cavities.
Single-piece injection molding; ≥60% airflow open area; ≥75% airflow retention; tool-free installation; ANSI faceplate compatibility; additive manufacturing embodiment.
Insert as sole acoustic attenuation component in HVAC terminal unit; no supplemental plenum box; ≥10 dB TL across 200 Hz bandwidth (ASTM E90); drop-in retrofit.
Multi-frequency Helmholtz sub-bands; shared plenum cross-talk reduction; distributed multi-register deployment with combined attenuation coverage; two-register shared-plenum system.
Replace non-attenuating register faceplate; passively attenuate duct-propagated sound without duct modification or power; tool-free ≤120 s install; frequency-tuning selection method.
The Voxnil Cover Plate replaces the standard register grille entirely. The attenuation mechanism is co-formed within the faceplate body itself: labyrinthine resonator channels and Helmholtz cavity arrays are molded into the plate cross-section during manufacture.
No throat insertion required. No plenum box. No modification to the duct or existing register frame. The plate mounts identically to any standard grille while delivering ≥10 dB transmission loss across the 250–800 Hz band — targeting the most problematic HVAC noise range for occupant complaints.
Register faceplate with co-formed labyrinthine resonator geometry within plate body; passive broadband attenuation 250–800 Hz (ASTM E90); no separate attenuator insert; no powered equipment required.
Helmholtz cavity arrays within faceplate cross-section; tortuous-path channels ≥3× plate thickness; resonant frequency tuning via cavity depth/neck ratio; injection-moldable polymer or co-formed composite.
≥10 dB TL across 250 Hz contiguous band; ≥55% open-face airflow area; compatible with standard ANSI register frame; ≤120 s tool-free field replacement; no structural duct modification.
HVAC terminal unit with acoustic cover plate as sole attenuation element; drop-in faceplate replacement; no plenum supplementation; retrofit to existing register frames.
Multi-plate distributed deployment; shared-plenum cross-talk attenuation; frequency-staggered plate arrays for broadband coverage; combinatorial deployment with VOXN-001 insert for dual-mode attenuation.
Single-pass injection molding of labyrinthine resonator geometry into faceplate body; field replacement of non-attenuating grille; passive operation without commissioning or calibration.
VOXN-001-PROV (App. No. 64/072,212) and VOXN-002-PROV consolidate into a single non-provisional under 35 U.S.C. §119(e) before May 22, 2027.
Hart & Cooley, Metalaire, Price Industries, Tuttle & Bailey, Broan-NuTone. Both systems manufacturable via standard injection molding — no retooling barrier.
Products licensed independently or as a bundled acoustic register system. OEM, aftermarket, and distribution channel structures available. Portfolio license includes both provisionals.
Jeffrey D. Retherford · 14597 Marr Court · Woodbridge, VA 22193
jeffrey@voxnil.com · (571) 597-9641
VOXN-001-PROV (App. No. 64/072,212) and VOXN-002-PROV consolidate into a single non-provisional before May 22, 2027.
Freedom-to-operate analysis complete. Primary risk patents require powered blower — absent from both Voxnil systems.
Hart & Cooley, Metalaire, Price Industries, Tuttle & Bailey, Broan-NuTone. Standard injection molding path.
14597 Marr Court · Woodbridge, VA 22193
jeffrey@voxnil.com · (571) 597-9641
Adjust parameters below to observe real-time resonant frequency, transmission loss, and geometric constraint compliance — the same physics recited in Claims 2–9 of VOXN-001-PROV.
OEM, aftermarket, and bundled portfolio licenses available for both products independently or as a combined acoustic register system. Standard injection molding path — no retooling barrier.