i have two sets of speakers that i want to connect to my Sony home stereo system, in the hope that it will increase and improve and make the sound louder.. the speakers arent the original ones that came with the system, but one pair is also Sony, and the other pair is Pioneer, the impedance of the speakers are all 8 ?, and on the back of my stereo system it says impedance use: 6 - 16 ? .. so will connecting the four speakers not be a problem, and will they increase the sound, even when the volumes set to max?