when i turn on my sub i can barely hear any sound. the amp is on and i can tell that the sub is on but the volume is very low. even when i turn up the volume on the headunit i cant even tell the sub is on. any advice?

alpinr 1241d type-r 12"
jbl px600.2 amp
alpine cda-9805

i rechecked the rca connections, made sure the ground was secure, tested the voltage with a multimeter to the amp and its fine, fuses are fine, turned up the sub level on the hu, not wired at 8 ohms, changed the gain, rechecked the polarity several times and its all correct, set the filters to every setting.

i have no other amps or subs to test with.

any other advice?

 

If you've already checked out everything else, make sure the sub isn't out of phase (actually, you'd still be able to hear it, it'd probably just sound like crap)...that's the only thing I can think of other than what you've mentioned. Otherwise, recheck the ground on your amp and all other connections once more...hopefully you didn't buy the sub used.

 

check the level of your gain. if it is all the way at the bottom, you will not hear anything. turn it up a bit and see if that works. also, make sure that the sub-level off ur headunit is turned on/up.

 

Here's a little bit of a ghetto test. Bring the sub into the house and try playing it on your home stereo (if you have one). Dont put the volume up too high!!! House speakers are rated at 8ohms your sub is rated at 4ohms (2ohms if you connect both voice coils). If you hear sound from it, its your amp... if not, its the sub.