What do you guys think about the difference that 2 isd's would have over 4 isd'd? the room is 22x17x8. i am going to add 2 more isd's to my 2 i have now. there will be 2 stacked in each of the back corners. what do you guys think of the configuration? right now i have 2 stcked in one (left) back corner. when i get the other 2 i am going to stack them in the (right) other back corner. what will be the spl advantage with adding 2 more? i love this forum and enjoy the replys. thanks guys and wish me luck!