If your daughter plays travel softball you will know what I am talking about. I have searched the internet for hours looking for examples with almost no luck. I am looking to build a 12v system that will run off a car/marine battery. It will need to have at least one subwoofer (preferably two because 10 year olds love their bass) a couple of smaller speakers, amp, and a head unit that will accept our I-pod. All of this will be in an enclosed box wheeled around on a a heavy duty hand wagon. Thanks in advance for any suggestions, or sites that may be of help.