With a noise level of 37 decibels, the PT-VX425N has a fairly loud noise level compared to most of the other 10000:1 contrast ratio projectors that have been around for a comparable time to this projector. The average noise level of data projectors of this spec and age is 34dB.
It may also be worth also looking at one of the alternative 37dB noise level multimedia projectors currently available including cheaper projectors such as the Panasonic PT-VX420 (£676.79).
If you would consider a projector with a louder noise level then you might want to look at the Vivitek DH758UST (£1,069.63) (37dB), or the Panasonic PT-VW355N (£939.76) (37dB).
What does "noise level" mean?