> Driver types don't matter. What matters is FR at the ear drum.

While this is technically true, planar drivers by design are able to deliver a more linear response than dynamic drivers are able to. Driver types AFFECT FR at the eardrum.

That is why dynamic drivers have roll-off in the treble and bass, and why good speakers have multiple drivers to cover different parts of the response. Trying to get all of them to cover 20 hz to 20 khz has its drawbacks, and we can see that in most dynamic driver FR graphs.

> I believe your "low res" experience is due to marketing telling you that planars are "better" and "more advanced" making confirmation bias kick in

Definitely not, I am not subjectivist by any stretch of the word, I argue with audio magic believers all the time, just check my comment history, lol. I'm a recording engineer. I know how this stuff works, it's my job to understand it.

In this case, FR at the eardrum is different in every headphone, they even change based on how the cups are positioned on your head, and FR measurements that we have of them are only accurate up to 10 khz, and even then, they're still smoothed over. There's tiny little differences in the response that account for a driver's properties, which is why with current tech, we can't EQ KSC75 to sound like Susvara.

Then, you start getting into the fact that some drivers, measurably, objectively, distort the more you mess with them, compared to others. Planars TEND to distort less, but there are plenty of dynamic drivers that are fine too.

In my experience, the HD6X0 series is not a driver type that handles EQ well, at least below about 400 hz. Treble/Mid EQ works just fine on it, which is why you can fix the recessed treble the 6XX has without issue.

But the bass... good god. It becomes a mud canon with only a little bit of a boost... Then again, it's a mud cannon at stock too, it's just bloated and has no definition whatsoever. HD600 handles this far far better, though the bass overall is reduced.

No, the reason why it sounds that way to me on some headphones is because a lot of driver adjustments are done with dampening, and the 6XX (my main dynamic drivers I personally own) are over-dampened, and it's very obvious when you listen to them.

Like you said, all that really matters is FR at the eardrum. My Ananda are heavily EQ'd, and even when using the same exact setup, measurements, target, etc etc, the Ananda do not have any of the negative qualities I'm used to hearing from the 6XX.

And I know it isn't in my head, because I have level-matched tests (done within 0.1 dB with an SPL meter) with them for people who have ZERO idea about how anything audio-related works, not told them what's what, and they report to me the exact same thing I hear. As in, my fucking mom noticed what I said without me asking or prompting anything related to the sound, and she barely understands how to open files on a computer.