OK, the Harman curve for headphones has been puzzling me. I have set up a "headphone system" fairly recently which I'm still tweaking when I have time. I've started EQing my headphones either via Morphit, or ReaQ with settings from github (typically Crinacle or Oratory1990 settings). On both my Stax Sigma and Sennheiser 280 PRO, I get way too much bass with occasional distortion, when I use the Harman correction in Morphit, and tend to much prefer their Diffuse Field correction. I'm not done exploring the github settings but they seem to work fine.