one thing i concluded from my measurements (taken with digital spl and producing sine waves) is that it is incredible inaccurate for the higher frequencies. The measurements are totally of and if you start correcting it above lets say 5k it will sound very out of tune. I think this is due to the fact that its very hard for tweeters to reproduce a powerful sine wave!! i have no validation for this but its what i concluded from my measurements....correcting it above 5k with this method will make the highs sound extremely of!... below that however you should be fine.