I'm having a problem with the radio on my 99 Bravada, Everytime I go over a bump the front dash speakers make a buzzing sound. The speakers work until I hit the bump. They will buzz until I press the power button on the radio and turn it off, couple seconds later I turn it back on and all the speakers work fine again till I go over another bump. I thought it was bad speakers, so I replaced all of them with BOSS Audio speakers and upgraded to 4x6 dash speakers and they still do this. Would the radio be the problem? Does my vehicle have an onboard amp? If so should I suspect that? Please help as I'm getting very frustrated when I'm listening to some of my favorite songs and all the sudden it's replaced with an annoying buzz sound

 

Sure "sounds" like a bad solder joint within the radio. An easy fix if you are comfortable with taking the radio apart and re-flowing solder joints, otherwise time to just replace the radio.