I just calibrated mine for the first time ever, only had the system for a year. I only used the pink noise and was surprised to find that my ears are actually reasonably accurate. My sub was the only offender in the group. Once I turned it down, my CD's sounded much more natural and not as booming as they had been in the past. I decided to recheck at 60db and found it off a little(User error?). I recalibrated at 60db and tested at 70, 80 & 90db and all speakers read the same.
I would think that the only reason to recalibrate would if the room has changed in some way, a new piece of furniture added or removed or the speakers had to be moved for some reason. Or any of the above previously mentioned.
I am hoping to get a setup CD soon and try out the calibration at the different frequencies to see if it gets any better.
