Kevin:

2db can be quite a bit when you are taliking about the imaging between speakers. I find that mis-calibration of less than 1db is obvious in my system, although admittedly it is used for mixing, so it's more critical that it be calibrated as closely as possible. Overall, I would consider fine-tuning by 2db quite useful! If all your speakers were perfectly flat throughout the full bandwidth, the test tone from the 950 and full bandwidth pink noise would yield the same trim settings. Since no speaker is in fact perfectly flat, it makes sense to exercise and take into consideration as much of their bandwidth as possible, rather than a narrow-band "snapshot" when doing a calibration. This is why professional users do it this way.