i am running (2) 15"D2 Btl's in 6 cub. ft. @ 32hz right now. the amp i am using is a zx2500.1. what is a safe or optimal freq. to turn the amp to? is this something that is done by listening or is there a general rule of thumb.

i am just noticing that the higher notes in almost all the songs i listen to, are almost not even audible. the lower notes are def there but what would correct this "problem?"

i think some people say 80 but i just go with what I think sounds best, just mess with it.

Some nice Mid bass speakers up front will correct your "problem." Sub woofers are meant to play sub-bass frequencies. You could tune higher also, to like 35-37 if you REALLY want to. I don't think you can damage the subwoofer by playing too high, it's too low you have to worry about. No lower than 1 octave below tuning frequency.

Example: You're box is tuned to 32Hz, don't play lower than 16Hz.

ok thanks. i am going to look around on the forum to get more info. appreciate it