Active low-frequency noise control

Low-frequency noise is an unsolved problem. We're solving it.

Walls don't stop it. Barriers don't bend it. Distance barely dulls it. Phase LF cancels low-frequency noise at the source — with clamp-on active noise control that installs in minutes on the equipment you already run.

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Fan discharge — sound pressure spectrum
Untreated With Phase LF Control band 40–250 Hz
01 The Problem

The noise everyone hears and no one has fixed.

Below 250 Hz, sound stops behaving. Wavelengths stretch to meters, passive absorbers become uselessly thin, and barriers are simply diffracted around. The low hum from fans, generators, and industrial machinery carries for kilometers, passes through walls, and drives the complaints, ordinances, and permitting fights that stall projects. The industry's answer has been mass and distance. Neither scales.

40–250 Hz The band where passive treatments — foam, panels, barriers — quietly stop working.
>1 m Absorber thickness needed to passively treat a 63 Hz tone. Nobody builds that.
km-scale How far low-frequency noise carries past the fence line, long after high frequencies fade.
#1 Low-frequency hum is the leading driver of community noise complaints around large facilities.
02 The Product

Clamp-on active noise cancellation for large fans.

The Phase LF duct unit clamps onto the discharge of the fans you already operate. Reference and error microphones feed a self-tuning DSP that drives anti-phase speakers inside an open duct section — cancelling the fan's low-frequency tone in the air, with zero impact on airflow and no modification to the fan itself.

ERROR MIC ANC DRIVERS DSP AMP CONTROLLER REFERENCE MIC DUCT SECTION TOOL-FREE CLAMP COLLAR EXISTING AXIAL FAN (shown for reference — not included)
Fig. 1 — Side cutaway. Unit clamped to fan discharge; airflow unobstructed.
15 dBUp to — LF cancellation
40 lbsUnit weight
5–10 minInstallation
  1. Clamp Seat the collar over the fan discharge ring and hand-tighten. Fits standard guards — no drilling.
  2. Plug in Line power only. No connection to fan wiring or building controls.
  3. Press start The controller self-calibrates and converges on the fan tone within one minute — with the fan running at full load.
Specifications
Control band40 – 250 Hz
LF cancellationUp to 15 dB
Adaptive algorithmFxLMS, self-tuning
Convergence time< 60 s after power-on
Fan compatibilityAxial, 25 – 49 in diameter
Airflow impactNegligible — open duct section
Equipment modificationNone
Supply100 – 240 VAC, < 50 W
EnclosureOutdoor, weather-resistant, −20 to +55 °C
Unit weight40 lbs
03 Applications

Wherever big fans and engines hum.

One standardized unit. Any common large fan or rotating machine. No custom engineering — and before/after dB spectra provided with every installation.

01

Air cooling systems

Data center dry coolers, CRAC units, and chiller fans — the blade-pass hum that defines a facility's fence-line noise.

02

Generators

Standby and prime power gensets whose firing-frequency drone carries far beyond the pad.

03

Industrial equipment

Process fans, blowers, and rotating machinery on plant floors and rooftops.

04

HVAC & chillers

Commercial rooftop units and chiller plants operating next to offices, hospitals, and homes.

05

Heat pumps

Large air-source heat pump installations facing residential low-frequency noise limits.

06

Compressors & pumps

Continuous-duty compressor and pump stations with persistent tonal noise.

04 Get Started

Quiet the hum. Keep the airflow.

Tell us about your site and the equipment you run. We'll tell you what Phase LF can take off your spectrum — with measured before/after data from every installation.

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