I am trying to measure the SW response at my listening position. I am using REW with 1-octave smoothing just to get a gross idea. I am running from 20-200Hz with the crossover at 160Hz for testing purposes. I would expect each reading to be the same as the last. It isn't. In fact some readings are radically different, especially at the lower frequencies. I have turned everything off I can think of. I don't know what else to do about this. Any ideas? Unless I can get consistent baseline readings I won't be able to make valid adjustments.
I figured out the problem. I didn't have enough output. It turn out the lower the output the sloppier the reading, at least at low frequencies. Once I got it up to a reasonable level the readings were pretty much identical. There was a very slight variation but it was hardly measurable, not worth worrying about.
This time around I balanced the subs and mains independently and then balanced all four together for the final adjustment.