[podnosimyszafe]

I have already seen numerous videos about the research conducted by Harman that concluded in coming up with famous Harman Curve. Regarding methodology, I only recall something like "participants had two sliders to increase/decrease bass and treble". This makes me think, that while the results of this research are extremely valuable, there is still something missing - shape of bass and treble region.

There are (simplifying things a lot) two ways of boosting bass: bass shelf and bass slope. Example of these 2 shapes can be seen in bass shelf of Sony XM4 and bass slope of DCA Stealth.

Also not all treble regions are created equal. It is more visible in case of IEMs so I will use them to ilustrate my point (as far as I am concerned Harman also conducted this research for IEMs). Two IEMs with more less the same amount of treble can sound very different because of scoops and boosts within a treble range. Good example of this are IMO Moondrop Blessing 2 Dusk and Sennheiser IE600. More less the same amount of "combined treble" but in case of IE 600 it is achieved by making some of the frequencies boosted or scooped.

 

[castleofargh]

The slider for more or less bass and treble was for one of the early experiments/papers out of... IDK, I'd say 13? that lead to the final Harman target. But I still don't think they bothered testing too many bass response tuning. One because the lower we go the lower our sensitivity to variation(needs bigger change for us to really notice). And 2 because they found out that the biggest variations in preference between listeners were about bass, and well explained by high variations in seal quality, age and stuff like that. Which are pretty much per user per headphone problems, so each should probably fine tune to his preference/need and only care about the target as a good statistical reference, a good place to start.

Personally I don't like having any boost above 100Hz. I'd rather create a little dip in the 150Hz area from a counter EQ than leave the bass rising early. So I'm with you on considering other shapes for the low end that we might prefer. But at the same time, I'm only me ^_^. Maybe most people like the slower more progressive rise in the bass? IDK.


About trebles, the variations between users are huge and near impossible to measure accurately/consistently. And that is even more problematic with IEMs as the smallest change in insertion will shift the ear canal resonances. For a slightly longer ear canal, a difference in insertion of the IEM, or just a different tip that occupies a different volume, those resonances will have a frequency shift. That obviously doesn't oppose the possible need for a more custom curve for you or me. Just that's it's riskier to part from fairly smooth and gently rolling off when looking for a generic solution to please( or at least not displease) a majority of listeners.