i recently built a 4080 box, and put one 12'' alpine type r. I just realized that at high volume, the sub almost acts as if it is hitting something behind it, and the sub definitely doesn't sound 100% right. I was thinking the box may be too small for this size sub, and im really pissed because it took me weeks to build the thing. Anyways, any suggestions or help is greatly appreciated, thanks, greg

 

The sub may be bad -(these are my methods for checking a subwoofer that i've learned, although i don't claim to be a sub expert by any stretch of the imagination)

- you can also just put your finger on it while its thumping (not hard) and if it rattles alot then it may be bad --

if you press the woofer in while it's off and it makes a grinding sound or doesn't move it all it's bad

also try to tap it kinda hard when it's off with your finger and see if it makes any other noise than a solid "thunk", like a soft rattle

Alpine should cover these with warranty.. there may be better / more ways to check but those are what i have learned