Well I installed a mid's/high's amp. I am running a pioneer deck and alpine amp in my 01 stang. Now when i have the music playing you cant hear the vocals. You can hear the instrumentals perfect, but no vocals. I tried adjusting the amp and I can't figure out whats up.

 

It's been a while since I have messed with my amp. Its setting in the shed as a matter of fact. But there should be a 2 position switch in your amp that will turn the vocals on. I cannot remember the name of it off the top of my head but you wamy wanna check there first.

 

I have never heard of a car audio amp that can switch vocals on on off.

I would check the high and low pass crossovers. Make sure to turn the high pass to between 50-100 hz and turn the low pass off.