Loudspeaker for open terrace -suggestions.

[swak]

A friend of mine wants speakers for his 16 x 5.5 meter terrace (actuallz for a side of it). The 16(l) x 4(h) m front is compleately open, the two sidewalls are made of brick and the back is glass. The 16 longitudinal meters are arranged in three zones (without wall divisions), sofas on the left side, dining table in the middle and a billiard table at the right side.

So the idea is to place a pair of relatively small boxes on the ceiling about 1m from the open-side front, with the speakers fireing to the inside of the terrace and into the back glass wall. The boxes would be angled (about 70degrees) downwards. These boxes would do 150-20Khz, and two subs placed right below each box would complement the lower end. There is a behringer digital corssover coming for the ease of setting it all up..

Is this a good arrangement?