Does it matter where i install the line out converter?

i have a jbl system in my car it has. trying to hook up an after market sub i hooked up the line converter to the wires of my sub although the sub isnt receiving much power it donesnt even hit my amp is a sony explode 600 wattt 4 channel amp now ive seen it hit before before i bought it from some guy but when i installed it in my car it dont work right i also have the amp bridged to put out more power but **** aint hitting. could it be because the converter is hooked up to the sub wire that are powered by a factory amp. or does that even matter? amp is hooked up to a factory head unitDoes it matter where i install the line out converter?
Whats the name of the line out converter?Does it matter where i install the line out converter?
go to one of your rear speakers and do it there,keep it away from the power line running the amplifier and keep the RCA cables away from that power wire too.some are fixed and some are adjustable follow the instructions in the package.any RCA cables running to close to the power source running the amp can cause a high pitched sound coming threw your speakers and you don't want that.and i must say line out converters can be a pain in the butt there is nothing like the right head unit that's set up to do the job.if you already have a powered jbl system from the factory i would recommend a good car audio installer before you create more problems then you solve.