ok, first things first is for you to check that the amp is connected and the power is on. one of the big problems i seem to find is that noone seems to earth the amp correctly causing it to fail, use some sand paper or other abrasive to scrape paint back to bare metal. If that is fine then take the sub out of the box and make sure that the magnet to cone cables are fine and there are no cracks visible. Always make sure that you run power cables away from speaker cables as this causes major interference. It could also be that you amp isnt up to the job of powering the sub, the rms output of the amp needs to match or be lower that the input on the sub, if you have got a 1500w sub it doesnt mean that you need a 1500w amp. If you are using the sub just for bass then the best bet is to bridge the amp over all 4 channels and if there is a 'lp' switch then flick that on. Make sure that all your cables are in the right spot and that the remote cable from your head unit is connected correctly to turn the amp on. If all else fails then take your sub out and connect it to a hi-fi in your house to see if its working. Hope this helps
James Best
January 2009