mp3 player or stereo on atv

[coaxxx]

has anyone done this and if so how?
ps i know there are pre-built stereos for motorcycles and atvs but im looking for something simple i can build.
really all i want is an mp3 player with desent sound

buy an mp3 player, put it in a backpack and use the earbuds...
i have a walmart camelback rip off that has a waterproof pocket for an mp3 player

[coaxxx]

i tried that and only problemis i can hear when i need to shift...lol
so i was looking for something external