Systems and techniques for cancelling fan noise by providing an anti-noise waveform are disclosed. In some embodiments, the systems and techniques include receiving, at a fan, a pulse width modulated signal from a power supply. A fan blade of the fan is rotated at a spin speed that is measured by a first sensor. A second sensor detects a position of the fan blade. Based on the spin speed and the position, an anti-noise waveform is generated that is configured to cause destructive interference with a fan noise of the fan. An audio signal is output that corresponds to the anti-noise waveform to cause destructive interference with noise caused by the spinning blades of the fan.
