Unlike a monitor, a projector produces operating noise, which can be distracting, especially when watching films, if it's too loud. The source of this noise is the fan and, with DLP projectors, also the colour wheel. In technical documentation, projector operating noise is usually given in decibels (dB).
Typical projector noise levels are in the range of 32 to 35 dB, and because of the logarithmic scale, a projector at 35 dB already emits twice the sound energy of a model at 32 dB. The threshold of hearing is the zero point of the scale (0 dB); a very quiet room is around 25 dB. A projector at 32 dB is therefore clearly audible, but quieter than normal room volume.
LED projectors also need cooling, albeit to a lesser extent. In eco mode, the need for cooling is reduced, as the lamp or LED unit also produces less heat in power-saving mode. Fan noise therefore also decreases, but not the operating noise produced by the colour wheel in DLP projectors.
