guys, when i turn up my system (pioneer h/u, vibe amped 12" system

) to only 20 out of 50 it starts cutting out and is embarrasing :embarassed:. i have used extra negatives to make sure it is earthed properly. my question is, what can i do to stop this happening?
can i use a larger amp battery or do i need to change the alternator for a more powerful one?
