well mine is silent, its the filter of choice in this price range on many forums and tetratecs support is the best out their, they will replace anything foc
I use EX1200 alongside my eheim 2078 and I do not hear any to be louder than other
normal price, but this 1200 sounds like an ol perkins diesel engine, they are not very stable and start to draw in air making them very noisy , i had 2 of these units and had to get rid of both. dont go above the 900.
very good filter, not sure its such a bargain though. http://www.pet-supermarket.co.uk/products-Tetra-Tetratec-External-Filter_CA4094.htm slightly cheaper. Not voted.