speaker problem

Hi have dvd cd deck installedand have RCA outs to after market amp,  back speakers run off  the after market amp in the trunk useing the RCA's. i also have  subs connected to another amp useing sub wire on the deck the sub works ok, but you can here voices not just sub sounds is this right .the front speakers are on deck power to the factory amp, they work fine. the other  problem i have is the back speakers sound ok but there is a clicking sound coming from the back speakers, when i turn off the right and left front and the right back speaker, the left back speaker has no sound. but it still has the clicking sound. when i turn on the right back speaker and turn it up, the left and right speaker both work. is this telling me that the amp is not a 2 channel  amp and what  is the clicking sound. ? this in a 2000 impala ls.

How many RCA outs do u have on your deck ( front, rear, sub) and how do u have them wired?Mastermindz

Fronts, rears, video ins and video outs and sub. RCAS . rear rca's go to amp in the trunk, fronts are on deck power  connected to deck by wires from harness in the dash, they run to the factory amp then out to the front speakers using factory wires. sub RCA to a amp and to the sub in the trunk . 

Ok I think u might have your sub amp lpf to high try setting it around 65-100 hz, and for the clicking noises on your rear speakers, at any point do your RCA wires cross any ground, power, or any other cables that could produce interference? Try lowering the gains and see if it gets rid or minimizes the clicking noiseMastermindz