I'm considering options for powering a small backyard 5.1 setup. The longest run is about 100ft from the source. The sats are based on the CHR-70 (4ohm, 22w max). I am not at all concerned about them being loud, as the neighbors are very close all around. Three options I'm considering: 1) small av receiver at the source (Sherwood r-904n pretty much only one that will fit at source) 2) external multichannel amplifier without much size constraint, and 3) powered speakers running line-level from preamp at source. Can anyone give me recommendations for or warnings about the 3rd option? Is there any chance using a spare 300w 12v landscape lighting transformer would provide anything close to good sound with a tripath/chipamp in each speaker? If not, what is a decent, reasonably priced power supply for the powered speaker approach? This will not be a heavily used system, and given the low power requirements of the speakers, would a SLA battery approach (recharged overnight on a timer) be a cheap/decent sounding approach? Just looking for a little inital guidance to get me going... budget is about $300 for amps and PS... speakers already paid for.