Yeah.., I know women do typically hear higher frequencies.., but for me that wasn't the case (until the last few years). My wife has great hearing.., but for years I was capable of detecting higher frequencies than she could.

I had a hearing test not too long ago.., and I do know my higher frequency range has declined. I attribute that to the many years I spent playing in rock and alternative bands. I played keys and guitar. A lot time was spent with my Gibson or Fender standing in front of a Marshall full stack (my ears would ring for days after doing some shows).

I tested other keyboards I have too.., and I'm almost certain it's down to the sample quality of those particular notes. Which isn't too surprising either considering that the S series is the semi-pro market for Yammie. Add in compression of sound sets and things like this can become an issue for those I guess that have hearing that may be more sensitive to that range.