So I decided to put an amp in my 06 cooper s to help boost the sound and now I have no sound coming from the rear speakers. My cooper doesn't have the hk upgrade. This is what I've put in so far:
wired in a line out converter to the stock hu just for the rear speakers
Installed a Dual brand 600w amp, power and ground from the battery in the boot, remote from the line out converter
ran wires from the amp back up front to the speaker wires

A few months ago I put Alpine 610c's in the doors and they work perfectly
to test all the new equipment I just put in I hooked the amp up to these and sound came out.
what is different about the rear speakers that my amp won't power them?

 

Are you powering rears with hu only? If so why the converter? Doesn't the hu provide speaker level output?

I'm no expert.

 

I'm using the stock hu it doesn't have a line out