Audio Systems: car stereo system, car stereo system, pioneer stereo

Question
I put in a pioneer stereo system and new wiring to all speakers and a sub woofer. I am noticing that when I step on the brake the sound goes lower and sometimes the right rear speaker sounds static like a short but it is not all the time and it is only when the music is playing. I don't think it is a blown speaker because it is intermittent. Can you tell me if both problems are related and if you have any ideas how I can find the problem? Thank you for your time.

Answer
I dont think both problems are related.  but the break one is strange.  I would sugest running a separate power wire from the battery to your cd player.  10 guage wire is plenty.  hook it up to the constant power on the cd player (usually the fat yellow wire). Make sure its attached firmly to the battery and put a fuse no less than 12 inches from the battery on it. (15 to 20 amps) Run a new ground as well.  dont use the black wire from the factory, find a place you can screw down a ring teminal to the body.  sand the paint off, screw the ring terminal down tight.  use 10 guage as well.
If your cd player's red wire is fatter than the yellow than thats the one used for power and this is a more difficult fix.  DO NOT wire the red wire staight to the battery.
As for the speaker crackling check the connections to it.  maybe solder the wires to it and see if that helps.
Good luck!