ios 6.0.1 AV problems

I have been trying to get a speaker dock for my iphone 4S that would charge my phone as well as play music, however, whereas the iphone will charge on 99% of the systems while docked, it will not play through the speakers. Additionally, on one Sony system, the phone wouldn't even charge on the dock. On one JBL system, the unit would work as described because the JBL amp up app that was meant to work with it would not open on the iOS 6.0.1 operating system on my phone. I've tried multiple options, multiple systmes, turning the phone on and off, etc. Finally, I just bought an apple charging dock and a Jambox bluetooth speaker. While this does solve my problem, it is not ideal and I would still like to know why the iPhone 4S running on iOS 6.0.1 will not work on docking systems.