Free online fan noise generator

What kind of noise is a fan?

A fan is closest to pink noise, not white. Its energy falls away as pitch rises rather than sitting flat, which is why it sounds softer and rounder than the hiss most people picture when they hear "white noise". If you want the full comparison, we went through it in depth.

But a fan is not just noise with a slope on it. The part that makes it a fan is the slow rhythmic movement as air moves past the blades. Its slower amplitude motion runs from 0.08 to 0.6 Hz depending on the fan. That sweep may be part of why some people who cannot sleep to plain noise find a fan easier to sleep to.

The seven fans, and when to use each.

Every fan here is shaped by where its energy sits in the spectrum and how its level moves. The three desk speeds also layer a low motor texture and faint flutter. The table lists the center frequency and slower movement so you can compare their foundations.

A lower center frequency sounds deeper and further away. The listed movement is only one part of the texture: the three desk fans keep their slow drift very shallow while their motor and flutter distinguish the speeds. The other four use a more audible sweep.

Do you need a louder fan?

Usually not. When a fan is not covering what is bothering you, the instinct is to reach for a louder one, but volume is rarely the variable that matters. A fan whose energy sits where the disturbance sits will mask it at a far lower volume than a louder fan pointed at the wrong part of the spectrum.

Voices and traffic live in the mid-range, so a medium or fast fan covers them at a volume a slow fan cannot reach. A rumble from a road or a boiler needs the low end, so ceiling or bladeless will do more than turning up a desk fan. This is the practical argument for having seven rather than one: changing fan is usually cheaper than changing volume, and easier on your ears across eight hours.

A rough test that works for all seven: if you would have to raise your voice to talk over it, it is louder than the job requires. The full three-step method is here.

How a synthesized fan differs from a recording.

A recorded fan is a recording of one room. It carries that room's reflections, whatever else was audible that day, and the microphone's own character, and none of that can be removed afterwards. It also has to loop, and a fan's sweep makes the loop point easier to catch than almost any other sound, because your ear is already tracking a rhythm.

A synthesized fan has no room in it and no take. It also has no motor whine, no bearing rattle and no dust, and it does not cool the room down at 4am or stop working in winter. What it keeps is the part you actually wanted: the airflow and the sweep.

How this generator actually works.

Each fan is a live signal chain, not a clip. White noise runs through a bandpass filter that sets the tonal character. Slow, Medium and Fast also layer a low motor band and faint irregular flutter, with a very shallow sub-1 Hz sine oscillator adding drift. The other four use the simpler filter-and-oscillator chain, with a more audible sweep.

All seven share the same pair of noise buffers, about 30 and 37 seconds long, as the app. Their different lengths keep the combined noise bed from returning to the same alignment for a long time. Switching fans crossfades over a third of a second instead of cutting, so you can compare two of them without a gap in between.

Try the other sounds.

If a fan is not the right texture, the noise colors are a different approach to the same job: white, pink, brown, green, grey and blue, or all six side by side.