I suspect this will lead a lot of people here who've rushed out to buy it somewhat disappointed, and worse, cause them to falsely believe this IEM is what the actual Harman target sounds like, and that their preferences don't match that target.
I see that you're back to your usual harassing form here
@GaryH.
The above is no more misleading than to believe that EQing IEMs to such a nitpicking degree of precision will actually deliver the same FR that the listening panel experienced during Harman's various tests, as anyone who's actually EQed two different IEMs to a target according to ear simulator measurements performed with other samples can easily attest ("they still don't sound the exact same, how come ?").
Between issues such as :
- seal / leakage :
A series of controlled listening tests were conducted to determine the preferred low frequency response of in-ear (IE) headphones. Using a method of adjustment ten trained listeners adjusted the bass level and frequency of a 2nd order low shelving filter applied to a high quality IE headphone...
www.aes.org
- lack of a constant transfer function between ear simulators for IEMs, to a degree that largely exceeds the degree you're nitpicking about, whether between different pinnae or different couplers entirely :
I wrote an article about the Harman Target Curve in Acoustics Today: The Perception and Measurement of Headphone Sound Quality- What Do Listeners Prefer? https://acousticstoday.org/he-perception-and-measurement-of-headphone-sound-quality-what-do-listeners-prefer-sean-e-olive/ I doesn't really...
audiosciencereview.com
- the well known issue of high-frequencies resonances varying with insertion depth, and more importantly the difficulty to predict how deeply different people will actually be able to physically insert and position different IEMs :
From Oratory1990
- combined, for active headphones with a feedback mechanism, with the variation in ratio between the feedback range, where the SPL will stay constant regardless of insertion depth, and the range above where it will vary,
- sample variation, which can span a spectrum from negligible issue to quite an important one (the TRUTHEAR looks pretty decent but
might already reach the degree you're nitpicking about :
https://crinacle.com/graphs/iems/truthear-x-crinacle-zero/)
it is utterly pointless to be nitpicking about 1 or 2 dB here or there for IEM measurements, and quite misleading to think that EQing IEMs to such a degree of precision to the Harman IE target will successfully deliver to anyone's eardrum what the listening panels actually experienced on average during Harman's own testing.
In addition to issues with the IEM Harman target in the first place, which was arrived at with fewer controls for various variables than the over-ears one, and, as a result, is a less foolproof exercise anyway, for example leading this alternative target to be strictly equally preferred by both trained and untrained listeners, to the "official" IE target, in Harman's 2017 article (
https://www.aes.org/e-lib/browse.cfm?elib=19237) :
Which deviates from the IE target by the tune of... 1-2dB in various places.
What you're asking both from ear simulator measurements and from Harman's - or others - research in target preferences is a degree of precision that they simply can't realistically reach.