2008 a4 quattro Aftermarket radio (non bose)
 

So I have had this A4 for about 3 months and finally decided to swap the radio out for a touch screen and add some subs. Every thing went well on the install and sounds great, but if I turn the radio up it sounds like the amp is clipping or cutting out for a millisecond but very consistent. It's a pioneer deck I installed and the wiring harness and steering wheel control are from crutchfield. I am baffled. I have replaced lots and lots of radios. I checked my wiring and everything is wired + to + and - to -. Any ideas or suggestions would be greatly appreciated. This is super annoying. Thanks in advanced!!