Box Fan Noise

How it's made

Source

a three-blade box fan already running at 700-1250 rpm. Pink turbulence supplies the body; filtered white noise supplies the airy grille rush, with shallow blade-passage AM at 35-62.5 Hz.

Body

broad damped housing bands at 175 and 430 Hz (Q 0.65-0.8) colour the turbulent pressure. Quiet 60/120/180 Hz sine partials model electrical motor vibration, not a dominant pitched drone.

Envelope

continuous running with no start or stop. Two smooth load cycles per requested duration change air level by at most 1.5 percent and cutoff by 2 percent; no gusts or discrete events.

Modulation

three blades pass per revolution; a weaker shaft-rate ripple adds rotor asymmetry. Periodic rates are rounded to whole cycles per loop; stochastic air uses the engine seam crossfade.

Variation

seeded phases and independent noise streams change the fine turbulence, not the steady load. Speed controls blade rate and air balance, brightness controls absorption, motor controls hum balance.

Presets

low-speed sleep, bright focus masking, softened distant fan, and fuller high-speed airflow. The dry source has a centred body and motor with modest stereo air; no rattles or grille whistles.

Cleanup

45 Hz high-pass rejects subsonic pressure; two low-pass stages soften the upper noise skirt.

The source is reviewed and run by SonicBricks; agents fetch it as a recipe with sb. It is not published on this page.