well my large 75 gallon tank makes alot of noise
if you tank has a wet/dry filter then try covering the "spill tank" or "overflow tank" with a towel (this will muffle to noise), you might also want to try and adjust the tube that connect the "spill tank"/"overflow tank" to the acuall filter, this will release any air pockets that can cause load sucking noises.
if you are using a hanging (dont know the acuall name but its the common ones that hang on the side of the tank) filter then try filling your tank. normally its the water making the noise.