Across all the multimedia projectors that have been on the market for more than two years the noise levels range from 37dB to 38dB, and the average noise level is 38dB. The Benq MW727 has one of the quieter noise levels (only 37 decibels) amongst 11000:1 contrast ratio multimedia projectors of this age.
There are a number of alternative 37dB noise level projectors currently available which you might want to consider including the Benq MX726 (£602.89) which is cheaper.
If you would consider a multimedia projector with a louder noise level then you might want to look at the Benq MH740 (£644.04) (38dB).
What does "noise level" mean?