Put a subwoofer system in my camaro.....one amplifier and when i turn it up the volt gauge bottoms pretty bad, even goes to the red zone.

I grounded the amp to the seatbelt mechanicism under the right back plastic panel. Sanded it to bare metal and grounded the wire to the stud. The only thing i did not like about that is the bracket i grounded to is just tack welded to the body. I guess i could run a 4 gauge ground temporarily frm the battery just to see if it helps.

I was also wondering would beefing up the power wire from the alternator to the battery, might help this.

Brand new battery installed also.........

Any ideas, ?? Or any else have had this hapen

 

Looks like you don't have a power flow problem, actually you're flowing too much out of the battery, faster than the alternator can replenish it!
Try a heavier battery cable, but I'm more inclined to say the amperage rating of your alternator just ain't cutting it.

 

^^^ agree, what battery, amp, and alternator do you have? what power is each.

 

If working properly your alternator maxes out at around 1500 Watts. What is the continuous power rating of your amplifier? If the total power load of the accessories, power train management stuff, lights, entertainment stuff, etc.. exceeds the output of the alternator, the battery will have to supply the missing power, and the voltage will drop as the battery discharges.
Also, is the input of your amp fused? With the amount of current draw you are experiencing, an unfused connection is asking for an electrical fire.

 

Along with what has already been suggested, throwing in a capacitor would be a good idea too.