i got 2 amps n a neon n power cap all earthed 2 the same place. let me explain, wit the engine off it n the system on it was runnin bout 11.4 on the alternator, wit the subs workin, turned on the engine, alternator went 2 14 n the subs stopped, not a lack of power there. looked in the boot n watched the power cap readin, at 14 the subs were fartin n not doin much, when that dropped 2 12 they began workin, which means the amp runnin them is prob got 2 much power in it, this could b cos all the earths r at the same point which i found out can b very bad, 1 dodgy supply could blow the rest, so i have 2 wait 4 my bloke 2 get home sunday to eliminate movin the earths to seperate points, if thats doesnt work its trial and error all the way