Personally, I'm not used to seeing very "high end" speakers set up outdoors, so I'm not very quick to suggest investing in amps of the caliber of Outlaw. A pair of M2200 monoblocks could be used to drive the two pairs (they can handle the 4 ohm load that's almost certainly going to be generated by wiring two speakers back to a single amp), but that's around $675 in amplification and a whole lot of power dedicated to some outdoor speakers. Seems like overkill to me, I guess. A 7075 costs about the same as that and would give you three extra channels, but I don't know what you'd do with them. If you had some speakers in an adjacent room that you wanted to have fed with the same signal going outdoors, you could do that, but there still seem like some less expensive options that would serve the purpose fine. Even something like
this curious beastie could do the job, and a pair of them would cost a bit over $200. The in-wall amp is probably only a good choice if you are opening up a wall to run wires or you are building new, since the front power connection would make me want to locate the amp's junction box low in the wall or at least behind some sort of furniture, but other "conventional chassis" small amps can be had for a comparable price (see either the used market or someplace like
Parts Express .
Is this basement a single open space? I'm trying to understand the need for ten speakers in the space with a stereo source being distributed to them all.
Distribution amps and similar switching and distribution hardware is a distinct market, so many of the names that dominate it are unfamiliar outside of that niche. Sites like
Home Tech sell a lot of this sort of stuff: IR distribution, lighting control, drapery control, home automation, racks, in-wall wiring, and unusual wall plates. An example of a distribution amp is
this 12x40W model, which could drive all ten of those basement speakers with two channels to spare.