wiring speaker lvl input

i am adding a sub and amp to my stock stereo, was wondering should i just tap the rear speakers wires with speaker wire and run speaker wire to amp then attach the speaker to RCA then attach to amp? Or do i tap the speaker wire to rca adapter to the wires behind dash then run female/female adapter then run a set of patch cables from behind dash to amp?

 

bump

 

Does you amp have high level inputs? If so you can tap the wire from you rear speakers and connect to the high level inputs. Then just connect your speakers to the amp. If not, then you will have to have an high to low level converter. You will run the rear speaker wires from the radio (either behind radio or from speaker) to the converter then run RCA's from the converter to the amp.

 

the amp has high lvl input on it i just didnt know if it was ok to just run speaker wire from radio to amp then wire on RCA adapter. does it lose signal the farther from source? thats why i wasn't sure if i tap right at harness then using barrel adapters run a better cable like monster and such BTW the amp is JL Audio Slash v2 series

 

You will be fine by splicing into the wire at the rear speakers and running to the amp. Since it has speaker level/ high level inputs you won't need any adapters though.