im measuring at three diffrent points. eigth space, quater space, and half space. eighth space, i get just over 140db at max SPL levels between 1,100 - 1,300watt at one meter (10-30% over RMS rate). but my high db ratings are for, like i said the high SPL levels. normal between 750-1,000watt at one meter, i get anywhere from 130-135db. when i hockup 4 of these bad boys, at one meter with combined strangth im getting just above 150db running the horns at high SPL levels. at 750-1,000watt at one meter, i read just below 150db for 4 horns. this is all done at quater space (horns set near a wall). in eighth space i get a little bit higher, mabey +3 or 4db, for half space its about -2 or 3db.