Something like
this would probably suit you well, you'd just need to find a set of indoor/outdoor speakers you like.
Under my porch I have a couple of Skar Indoor/Outdoor speakers and a cheap Pyle BT receiver. The receiver doesn't put out enough power to run the speakers above half volume, but even at half volume, it's much too loud to carry on a conversation. I'd recommend the Skar speakers, but they appear to have been discontinued.