The quietest noise level of 20000:1 contrast ratio data projectors that have been around for a similar time to this projector is 26dB, the loudest is 37dB, and the average noise level is 32dB. At only 29 decibels, the Optoma W331 has a fairly quiet noise level compared to most of the other projectors that were released one year ago.
We think you might also be interested in some of the other 29dB noise level data projectors currently available including the Optoma DS347 (£349) which is cheaper.
Multimedia projectors with a louder noise level that might also be worth considering include the Viewsonic PJD6550LW (£510.26) (32dB).
What does "noise level" mean?