Not dissimilar to me. I'm 56, and the hearing in my right ear is pretty good for someone of my age. My left ear has 'issues' at the top of the frequency range.
I'm still perplexed by anyone over 50 who thinks the treble on the 990s is 'unlistenable', because it's probably lower than the treble of well-EQd HD650s to a sub-30 year old.
At 30 your hearing's frequency range should be flat, and at -5dB compared to an average 18 year-old. At age 50 the average 50 year old loses 15dB at 8khz. At 60 it's closer to 25dB, so a typical 55 year-old is losing c.20db, which is 15dB below anyone below 30. Amir's measurements show maximum deviation from the curve at 8khz of +12.5dB.
Now we are the audio SCIENCE review forums, and the science suggests a 55 year old would need to boost the 990s by c.2.5dB to get a flat response (though also adjusting for other frequencies, too).
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