The difference in the 9-12k response here is really just crazy. The 45CA and 4128 you just put up are pretty similar, but the 45CA to 5128DF (comment on video offered that correction) in the first one here is wholly different with a huge dip. The 5128 then, in theory has a similar dip, but DMS’ ear canal (blue in 2nd) has a massive peak.
If anyone was still thinking they can use even 5128 data to EQ the treble, they need only look at that 2nd graph. 18dB swing there. This, FWIW, is that “measurement error” I rambled on about in a video.
