I fully acknowledge that my plots do not necessarily represent absolute reality and I appreciate what you are trying to do from a theoretical and scientific level. But as you said, it was never my intention to find a "Grand Unifying Theory" of headphone measurements. I'm a pragmatic, and just wanted to find something that works without the complexity of compensating functions (for each headphone enclosure) and HRTF (for each person.) I've the stated the premise of my methods numerous times in this thread and have never attempted to hide this. I've expressed caution and asked readers to take these measurements with a "grain of salt" (in post #1 of this thread.)
P.S. I'm tending to not like the solid plate tests, especially below 2-3kHz, because they either amplify and extend existing driver ringing, create their own enclosure based ringing (in which IMO is mostly filtered out by our ears/brains.), or exacerbate the differences between the peaks and the nulls. The effects of this are so severe that they mask and even dominate significant areas of the spectrum. What's really needed is an compensating impulse response for each headphone enclosure. I'll leave you to this.
Hi Marv, I certainly like the intelligibility of these "sort of free field" CSDs and trust that you must be doing something right if the objective results are meshing with subjective opinions of several people (whom you've brainwashed to your measurement technique before hand ;) just kidding! ;) ). I tend to view everything a bit more rigorously simply because I am in the field but can be pragmatic as well, so give me some more time to get to the idea that these tests really are better ;). The truth is, it is almost like saying "you guys have been using the wrong microphones for years, here's the kind of stuff you should be using". Dummy heads are expensive for a reason (well beyond the fact that the market is virtually non-existent hence the high cost of entry): the better ones have surface impedance which is close or aiming to mimic that of human head. It's probably closer to 2mm thick foam than purely anechoic.
Anyhow, please explain me in more detail what you mean by impulse response compensation for each enclosure. Do you mean using notch filter to compensate for the acoustic resonances? Again, I don't see the value vs. say a free field measurement with the unbaffled headphone?