So I have a theory that we could take tools commonly used in an audio mixing environment to gain more knowledge about how different headphones sound, but I don't have the gear to try and validate that. I have however done some listening in my DAW using various softwares and I think there's untapped potential there.

As an example it's common in mixing to have a mid/side EQ to independently adjust centered (mono) and side (stereo only) information. I tried simulating a typical sine wave sweep but for the mid and side signals separate and found both signals to have different peaks/dips from each other. My LCD-XC has a boost at 7-8k that is only present on the side signal whereas that region is slightly attenuated on the centered signal (for my hrtf anyway). Obviously I would need to do more thorough testing with actual measurement equipment to validate that, but it's an interesting observation nonetheless.