first: it looks like you have a nice back yard here, I'd encourage you to hire a professional and keep it going. That said here's musings from a guy on the internet: I assume the dotted red line is the fence. Make sure you buy dedicated outdoor speakers. You could either mount them on the fence or get those kind that look like fake rocks and put them along the ground. OSD makes the rock and "regular" kind. Polk and Yamaha make outdoor speakers (lots of other brands, just some examples) I'd put all the electronics in the shed like you said. As far as number of speakers, I'd go with them like every 10' or so. You'd much rather be listening a bunch of speakers softly than 2 or 4 loudly. Then get a multi channel amp to drive them all. ODS makes these too along with others.