Okay, I know this setup is not optimal, but i dont have the money to buy another amp right now so ive got to make due with what i have. I have a 4 channel 1400 watt Pyramid Crystal amp (what it is really capable of Im sure is significantly less than what it claims considering how cheap of an amp it is). My subwoofer is an Alpine type-R 1242, so dual voice coils (each 4 ohms), 500 RMS, and 1500 peak. My car audio knowledge is very shakey when it comes to figuring out the optimal setup and deciding whether to wire in parallel vs series and deciding whether to bridge channels.

Right now I have my four channels bridged into two channels (because I previously was running two subs). I have one of the two channels connected to my sub, which is wired in parallel. The wires for my other channel are simply laying loose unconnected to any sub. The sub sounds pretty good and I could just leave it the way it is and be happy with the sound, but I was just wondering if theres a better way to set this up.