Let me make a bold statement here:
If we have two different headphones with the same CSD plots, it will be not possible to tell a difference between them in blind testing.
Can someone prove me wrong? Are there other scientifically proven properties beside waterfall plots which can influence how sound equipment will sound? Because if there are not, then with Occam's razor in mind, we can assume that my statement is true.
If that's true, then if someone invents a relatively flat sound headphones with very quick decay across whole FR range, it could be reshaped to any other existing headphones with precise EQ (a longer decay could be artificially added by software).
I hope I don't sound like an ignorant, I'd really like to learn more about sound science. The first thing that comes into my mind is the interference between frequencies, for example if there is a constant sine wave at some frequency point it could also change response of others, however I haven't found any article proving this.