With a noise level of 39 decibels, the Vivitek DX3351 has one of the louder noise levels amongst 10000:1 contrast ratio projectors of this age. The noise levels of similar spec projectors that have been available for a comparable time to this data projector range from 27dB to 48dB, and the average noise level is 34dB.
Other 39dB noise level projectors currently available which you might want to consider include the Epson 1970w which is cheaper.
Other multimedia projectors with a louder noise level that you might want to look at include the Benq MH856UST (£1,150.30) (37dB), or the Vivitek DW3321 (£1,150) (39dB).
What does "noise level" mean?