I’ve come to the conclusion that all of these EQs in which specialists like Oratory1990, Crinacle, et. al try to make every headphone sound the same in an attempt to even out the frequency response of each and every headphone defeats the purpose of getting any specific pair of headphones. Why not just get the most neutral headphone and call it a day?
I’d guess it’s because you like the sound signature. Whatever deviations the creators of the headphones made from this Harmon curve was intentional and you happen to like them. Enjoyment is the name of the game.
I’m not sure how much consensus there is here about the most neutral headphone response. I think the best practical definition is “the response that would create the same sound pressure at the entrance of the ear canal when using speakers with flat frequency response at the correct placement in an anechoic chamber”. The difficulty is that the frequency response of a headphone depends on the type of headphones, the position on the head, the cups, and, according to the above definition, the anatomy of each individual (most importantly, head size and shape and size of ear lobes). If you want the best results, you need to calibrate your own headphones while wearing them using in-ear microphones.
Yeah, I think it’s fun… It’s not only neutrality though. I wanted to simulate the sound of my floor-standing speakers through headphones, so I’ve built in-ear microphones from foam pads, miniature condenser capsules and an old headphone cable. I can’t seem to build enough free time though…
A speaker system is my next goal. I love listening to music through great headphones, powered by a good amplifier, but…nothing beats sitting in a room and listening to music through a great set of speakers adapted to your room.
I believe that this assumption isn’t quite correct. The Harmon curve is based on the fact that due to the structure of the ear canal and the close placement of headphones with respect to the ear canal a “flat” frequency response would not sound “flat” therefore the Harmon curve deviates from a flat frequency response as way of compensating for these issues.
Now as to whether or not all headphones equalized to have their frequency match as closely as possible the Harmon curve (done in Roon using DSP and convolution filters) sound the same, well that’s just not true. The better the headphones, the less effect applying a convolution filter will have on their sound since good headphones are more often than not designed to follow the Harmon curve as closely as possible.
I suggest that you test this out for yourself if you own at least two different headphones. Listen to them without convolution filters and then with the correct convolution filter applied. They will still sound different and sound different enough that you will easily be able to tell them apart.
Of course you also have the option, using Roon’s DSP function, to apply whatever EQ you want and really customize the sound of the headphones to your liking.