"That is because you have power distributed to 8 or 9 devices so power distortion levels are very, very low vs. single driver measurements. "If you were to make an educated guess, how many decibels down would the addition of each speaker unit(or group of 2 or 3 units) would the distortion levels go. Would you expect that for each unit the distortion would drop one decibel, so for 9 of them the level would drop 9 decibels?
Jim Muro