Hi. My name is Joey Chang aka CelloJoe and I have been using a Rock the Bike Modified JBL Pro PRX 612 for over a year. I have ridden many miles with this speaker strapped to my xtracycle bicycle and used it in many settings from the street in downtown SF to festivals all over the west coast. I have used it to busk at the How Weird Street Festival where there were extremely loud sound systems one block away.
The sound quality is impeccable. The two 12V custom Rock the Bike batteries keep the speaker thumping for 4-8 hours depending on how loud I turn it up.
The speaker is very portable. At 36 pounds it is a bit heavy, but I have carpooled with it and have never had a problem fitting it in a full car.
The only problem I have ever had was when a friend plugged in the AC power while the batteries were plugged into the Nutrix connector.
I highly recommend the Rock the Bike modified JBL Pro PRX series speaker to anyone that wants thumping bass and high fidelity sound in a highly rugged bike tour worthy speaker.