23-07-2014, 12:02 AM
Yeah, it's very hard to be sure unless you're using calibrated headphones and a calibrated signal. Anything overmuch going on above 18 k is likely to distress and fatigue someone with very good hearing, but I doubt he'd be aware why. Even 17k is really really high, and most natural sounds gently roll off start around 10 k... Keyword being gently, so it's a good quality for a mix to have.
I'm grateful for comments and suggestions. Thank you for listening!