Arturia iMini User Manual page 5

Volume Controls the volume of each oscillator. Tap the on button to the
right to make sure the oscillator is enabled.
External Input Volume Sets the volume of external input.
Noise Volume Sets the volume of the noise module.
Noise Type The noise module in iMini produces two types of noise: white
and pink.
White noise is the richest of noises, having all signal specturm frequencies
at an equal volume level. For this reason, the noise module is used to create
different noises like the imitation of wind or special effects.
Pink noise is also often present on synthesizers. It is less rich in the high
frequencies than white noise. Also note that the audio output of noise can
also be used as a modulation signal (especially when strongly filtered) to
create random cyclic variations.