this is what i did and use daily. it is a goal zero speaker. REI has them, and sometimes costco has a roadshow for them. not bluetooth, but plugs directly into my iPod or smartphone. i mount the iPod in little suction cup thingy bob i found at target. speaker seats under the arm and has a little downward pressure from the arm to keep it from sliding. works perfect for me. you can also link two of the speakers together if you want. i find it plenty loud for my needs. the speaker has internal battery that i charge thru the lighter when need.
andy
andy

