Earfun Free Pro 2 - neutral tuning 6000hz (Patreon)

I finished a neutral tuning for the Free Pro 2 which should offer a similar spectrum to neutrally equalised speakers in a room and should sound similar to my neutral headphone target. They all do not sound exactly the same, but it was close to impossible to achieve this, also as the ear canal being the only sound forming factor for an IEM can even change during day and make the IEM appear to sound different in the morning or in the evening. After more than 2 weeks of tweaking I came up with a response which sounds really nice with my parciular Free Pro 2 unit and with my ear canal. I tried it also on some of my other units and the results were not that great with the newer units due to sample variation. Older units still sounded slightly different but close enough to be accepted.

Below you can see the final response measured with my couplers and with a GRAS in pink, overlaid with the Harman target in grey:

I think this is the only sensible way to compare it to the Harman target, if I reference them at 1khz the Harman target will appear even more off:

Nevertheless the Harman target appears nowhere close to a neutral spectrum coming from speakers. It sounds just wrong in all aspects.

Compared to my old "reference" tuning, you can see that they shouldn't sound that different overall, just that the current neutral should appear brighter with less upper bass, and slightly more lower bass:

Compared to the MH1 you can notice that both resemble each other quite well, just that the Sony MH1 has too much bass and too thin treble, despite these issues this may still explain why I always regarded the MH1 as one of my favourite IEMs:

Compared to the Etmyotic ER2SE you can see that the Etymotic has way more mids, although the overall tendency seems pretty similar, but also the lack of upper treble is visible for the Etymotic, it was always rated as 20hz-16khz only. The bass measures completely flat for the Etymotic, but is perceived differently due to the deeper insertion and probably some additional bone conducting effects:

I would also like to throw in a highly regarded IEM back then, which to me always sounded completely wrong: the Moondrop Blessing 2 together with the Harman target:

Interestingly the Moondrop mostly peaks where there should actually be a dip, I still wonder how this could ever become that popular.

As the final response will vary so much between different units and different ears, I won't delve into creating further settings for other ear canal resonances, as due to strong averaging among all the units that I own the final result may still be off to someone else and the work simply to no avail.

If there is interest I could offer on demand settings for particular resonances. The most secure would be to tune particular units towards particular resonances, this way I can ensure that you actually get what I intended. If this will sound correct to you is still unsure, as the response shown recreates the effects of my own concha to some degree. How others may perceive this despite the same ear canal resonance is unpredictable.

I am still keen on knowing how others may perceive this setting optimised towards their earcanal and a particular unit. I could purchase single units and create settings for these with the given ear canal resonance. I could offer such individualised units for maybe 100€ + shipping. It would cost me several hours to measure them precisely and tweak my settings towards the desired ear canal resonance. Another option would be to measure all my units and create an average out of them, and then offer settings for the desired ear canal resonances. But due to the high effort, I could do this for the hifi-level maybe. It depends a lot on what you desire.