popping on turn on and song change

I have dealt with a few popping issues in previous installs of amps and i know that at times, popping on turn on/off means bad ground. But i have never experienced it in song change before. The initial install was not done by me, but by an install shop, but then my roommate has had nothing but issues since. The wires were a jumbled mess and kept pulling out of their locations on the amps due to the sub box not being secured. The car is an 02 Acura Tsx. The headunit is a clarion Vrx775VD, the sub a planet audio 15" with a planet audio 950 watt 1-ohn amp. The rest of the speakers are stock and run off of a soundstream (tarantula) and also mounted on the sub box in the rear. A single 2 gauge power wire run to a fuse block supplies power to both amps and each amp has a 4 gauge ground wire running to a central location in the trunk, in the spare tire compartment. The amp being a 2 channel, the rear speakers and combined into 1 channel and the fronts combined into the other channel. When the system is powered on, the main speakers pop, and then they also pop during song change. As far as i can tell, the sub does not pop during either of these. So my question is, what would cause it to pop during those instances and how can i fix them

Also i noticed when i took it for a drive that i get engine wine noise from the speakers under acceleration

Check the ground to the CD player. If possible ground it to the chassis of the car, or better yet ground it to where the amps are grounded.There is no such thing as free installation!