so i have a pdx5 hooked up to an alpine type s 12" 4ohm sub in a truck box. it sounds good but i listened to a friend that has a 10' type r with a alpine mrp m450 amp and it blows mine away. could i have my sub hooked up wrong. on the back of the sub the two terminals in themiddle are conected together with the little jumper wire and the 2 wires coming from the amp are going to the outside conections on the sub. any ideas?