Here's a quick explanation as to why my earlier measurements of the Xelento (
https://www.head-fi.org/showcase/beyerdynamic-xelento-remote.22337/reviews?order=likes#reviews) didn't match those posted by
@jude in the main Xelento thread (
https://www.head-fi.org/threads/beyerdynamic-xelento.827372/page-78#post-14480482).
Firstly, my original measurements were diffuse-field compensated. This was done to match what InnerFidelity were doing at the time. As you can see, the agreement with
@jude's measurements is poor, though some of the peaks and troughs appear to be roughly in the same location:
Note the background color above. White = diffuse field compensated. I've tried to be consistent in that, when posting raw data, I always use a dark background. Here's the raw comparison (with a slightly different insertion depth):
Still not that great. The next issue was that I was using (and measuring with) SpinFit Cp100 silicone eartips.
@jude had used the stock Xelento eartips. Eartips always make a significant difference. So here are my Xelentos measured with the stock Xelento eartips:
Getting closer. The next issue was that I was using a conventional 711 coupler, whereas
@jude was using the latest "hi-res" (RA0402/RA0401) coupler from GRAS. This intentionally puts a strong damping on the half-wave ear canal resonance, which, in the case of shallow-insertion IEMs, can have an influence at frequencies well below 10 kHz. Here are my Xelentos, using stock Xelento eartips, measured with the GRAS RA0402 coupler:
Still not 100% perfect agreement, but these differences could be more easily attributable to unit variance.
The morals of this story, as I see them:
1) Don't use diffuse-field compensation.
@jude patiently spent an afternoon convincing me this was a bad idea, and I agree. Raw data is far easier when comparing with others, which is ultimately what we want to be able to do.
2) Always compare using the exact same eartip type and
size (
https://www.head-fi.org/threads/ety...and-your-couplers.908512/page-6#post-15108352).
3) Always compare with the same type of coupler. There are supposedly advantages of the RA0401/2 for manufacturers. I'm not entirely convinced that these "hi-res" couplers are ideal for end users, since ear canal resonances are a real phenomena, and (at least from my limited experience) the standard 711 couplers appear to get closer to what I hear than does the RA0402. But I'm open to persuasion if others have had the opposite experience...