So it's intentionally distorting sound? Even so, it could be measured and compared, with more complex sound patterns (as opposed to sine waves or whatever is normally used for frequency response).
Not criticizing, just stating OPs argument.
... and you cant measure it is at the heart of all audiophoolery. Either it reproduces source material as close to 1:1, or it distorts it tricking your psychoacoustic system to perceive a positive difference, for example by making the sound louder (wins every single blind test).