Hi Bruce,
Both the AP840 and AP650 are both excellent patio speakers. The main differences are in size of the woofers and the power handling capabilities. The AP840 has an 8� woofer and up to 200W power handling, while the AP640 has a 6.5� driver with 150W power handling. The 8� woofer will handle lower frequencies (bass) better than the 6.5� woofer due to the larger size cone. However, the AP650 is the best in its size and outputs plenty of bass and volume without being too bulky. If you have a large area to fill and, think about the AP840s but double check that the dimensions of these large speakers will work for your application.
CL/MA 1985