JL Audio 10TW3 D-4, 10" shallow mount sub. Under rear passenger seat/ down firing. Pre-made enclosure with a bit of added polyfill. I could | Nissan Frontier Forum
Adding Poly-Fil to the stock subwoofer to improve sound | VW Vortex - Volkswagen Forum
Ported sub build, lessons learned | DiyMobileAudio.com Car Stereo Forum
Fill your sub with poly-fil - Ford F150 Forum - Community of Ford Truck Fans
Adding Poly-Fil to the stock subwoofer to improve sound | VW Vortex - Volkswagen Forum
How to speakers have more bass, how much polyfill in sub box. M17 - YouTube