Bose subwoofer and amp

[smileynialley]

thanks for your reply.
I run a Kenwood head unit but there's no sub-out RCA, just the existing wiring loom and adaptors.
Surely that connector i posted is a way of adding an RCA plug to my standard stereo wiring is it not?
If i'm tapping off one of the existing speakers to add an extra sub and amp, could i not then re-power that speaker using the same amp i'm adding so that it's not lost?