Leaving aside the many other problems with your comment, I'd like to draw your attention to this better-informed comment from svantana:
> You could, for example, have a bunch of expensive headphones with frequency response that varies randomly in the [-1,+1] dB range, and a bunch of cheap headphones that are in the [-10,+10] dB range -- that would also show up as uncorrelated.
> Indeed, they did find a significant difference in magnitude response _error_, although the effect was quite small.
> You could, for example, have a bunch of expensive headphones with frequency response that varies randomly in the [-1,+1] dB range, and a bunch of cheap headphones that are in the [-10,+10] dB range -- that would also show up as uncorrelated.
> Indeed, they did find a significant difference in magnitude response _error_, although the effect was quite small.