I love my Preludes.
I had them in a ~10 X 20' room, along the long wall, less than foot from the wall.
I recently moved and they are now in a VERY big room, cathedral ceilings. And they hold up fairly well; the extra room for them to breath, able to pull further from the wall, etc, really 'breathed' some extra life into them.
They are now more sensitive to quality of recording it seems.
Most would say they arent up to the task of a room that big, but I am going to try a sub with them before I try a larger speaker, there is just something about the sound of these I am loathe to give up.
Depending on the recording, I sometimes find them a bit strident on the top, but am going to try also roll the tube in my Peachtree Nova, and am upping the amplification a bit with Red Dragon M200 monoblocks.