2 ohms or 8 ohms?

I'm about to hookup a single JL Audio 12W6V2 D4 to a Hifonics 600x1 W at 4 ohms. The sub has jumpers on it to connect to 2 (parallel) or 8 (series) ohms. Which one do i connect? Does it really matter? What happens if i dont connect any jumpers?

whats the exact amp you're using? Model number?

i'm running the Hifonics Zeus ZX6000

you're going to want to either wire it in parallel and run it off of just 1 channel or wire it in series and bridge the amp and run it that way. Wiring it in parallel and bridging the amp will clip the signal since it's an ohm load the amp can't handle in mono which will lead to destruction of your amp or sub.

I plan on bridging the 2 channel amp to 1 channel so i guess i'll be running the sub in series. Thanks.

You can wire it either way. It depends on what ohm load the amp is stable at... If its stable at 2 ohms Mono, wire it in parallel, if not, series to 8 ohms... Keep in mind, the power of the amp will be substantially lower if you run it at 8 ohms.

Or just exchange it for a 12W6V2-D2 and do it right the first time.