BP, welcome. The only "breathing" factor is that the back ports should be at least a few inches from the wall behind. The distances from the center of the mid-woofer cones to the three nearest room surfaces(floor and two walls)should be unequal, but there's no requirement that the distances be large. The M22s should be excellent in a room that size and some members have even used larger tower models in similar rooms.

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Enjoy the music, not the equipment.