So I have upgraded my rear subs and run them through a convertor and amplifier using the signal wire from the original subs.Sound is still Pony Now plan to take a feed from the 2 front 8inch speakers and run that through the additional amp then to my new subs
my question is do I need to put some kind of resistor on the original sub wires that I won't be Using Will the amplifier cut the output from the rear mids as well because of it thinking the subs are faulty as in not connected

 

My 2015 doesn’t have any issues with the sub disconnect but that may not be the case if a more recent car. Also no point amplifying the oem sub output as nothing there worthwhile.

 

You will most likely need LGD's (Load Generating Device) between the factory amplifier and the Sub amplifier to make things behave correctly. Gray LGD-60 would be the correct ones for a Meridian 380 system. If you don't use them thing get a little wacky as modern Class D amplifiers need to see a speaker load which is different than a amplifier hi level input. Some aftermarket amp and line level convertors already have this feature built in, if not they are cheap.