i put this in the subwoofer section because its related to my subwoofer even though its about amps. my sub is an AQ hdc3a 15" 4.5 cu ft box tuned to 36 hz. my quiestion is if its better to have an adjustable subsonic filter or preset to a certain freq...i have a older rockford power bd1500 amp i want to use but its subsonic filter is NOT adjustable and i searched and cant find what its set at. one guy said 25 hz but cant really trust everyone. say it is 25 hz then if my box is tuned to 36 hz would that be bad?