Quote Originally Posted by reptar View Post
I'm using a Mercury audio m800 amp. Not really sure about the the exact dimensions of the enclosure but it's made of fiberglass and is shaped a like a cylinder. Sakto lang lang sa spare tire well
Was the enclosure properly designed for the sub? I suggest you use a slim sealed rectangular enclosure (made of MDF). Focal recommends a sealed enclosure with a volume between 15 liters (0.53 cubic feet) and 25 liters (0.88 cubic feet) for the 25a4 (as per specs). To adjust loudness, you just have to lower the gains on the amp to provide a cleaner signal for the sub.

With my 10" RF sub before, I used a 12x12x12 (inches) sealed enclosure that came out to around 0.75 cubic feet which was good enough for in-car listening.