I purchased mine with the saddlebag extension kit, which is basically a longer cable to reach in the saddlebags, but noticed that one of the lines, cause it comes with two, was making one of the speakers not play.
SO....if you experience sound not coming from one speaker check the connecting cables from ipod to interface before you go batshit crazy trying to figure it out. It happened to me and for a whole day, a second RF PBR amp, one week later it still did to only figure out it was that damn cable. switched it out and it worked.
"Just put that hammer down and give it hell" -Jerry Reed.