@solderdude
I tried many positions and different amounts of pressure. The plot above is the best I could get out of it.
But I just remeasured the K371 with a better setup. The old coupler was made of thin plywood. Now I am using a piece of solid wood in 35 mm thickness. I drilled a hole for my Beyerdynamic MM1. This way I do not have to use the in-ear mic (EM258) which might have had some sealing issues with the cable on the front and maybe some roll-off due to lack of mic calibration.
This is what I get with the new flat plate coupler (w/o compensation):
Now I have the correct low-end extension without roll-off!
Does not change a thing with my personal sealing issues, unfortunately. Still good to know that my sample is within spec at least.
If you ask me, the flat plate and cheek simulators are of only little pratical use as long as you do not compensate for the tilt and at least a fraction of sealing inteference. That is also why most headphones models do not sound right to me when eq'd to Harman, based on generic measurements.
You are definately on the right track with the "seal plots". Too bad there is no common standard for bass evaluation and sealing, yet.
@thewas
Thank you for trying!
As already mentioned, I am one of those guys who rate the Harman target as too hard in the upper mids. The Nighthawk as a concept is interesting because it does do pretty much the exact opposite by attenuating that region instead of boosting it (as actually a lot of AKG cans do, which I rather dislike). Personally, I think that this attenuation takes away the hardness of the "forced" frontal localization and makes the sound much more long-term enjoyable and spatially diffuse.
Maybe I can encourage myself to adapt to the "hard" Harman for a longer period, as an experiment until say the beginning of January, then check my setting again and see if it still works.
Maybe you want to join this experiment, starting at the other end of the scale?
Regards
Dreyfus