x2. you will need to find the aux turn-on output in the back of the head unit (yes, it has one, but make sure it's not an antennae remote, and sometimes, there is no wire in the terminal) or, there is sometimes a feature on the amp to sense voltage offset through the high level inputs (recently saw that on a kicker kx500.1) or low level rca signal sensing. which comes back to the amp. depending on what it is, it may have high level inputs, where you just tap into the rear speaker wires and hook to the high level inputs, or buy a line out converter, and tap into the speaker wires and plug rcas into the box.