> There should exist frequencies impossible to reach for anyone but post-pubescent men.... Of course that would make it teen-age verification at best.
Yes and no. Like geology, the more you dig into audio, the more is uncovered and available.
A child/teen with a deep voice has very unique perturbations that don't exist in other cohorts across feature sets. Adults may share some characteristics, but not at the levels found in specific age groups.
What about women, though? Do they not get to age verify themselves? :P
Women also undergo voice change, just less pronounced.
Now the problem turns into being able to tell men from women.
EDIT: this of course isn't a serious proposition.
Then again I wonder what effect this would have implemented on e.g. a porn site. Women also watch porn, but with enough tuning I think it shouldn't produce too many false positives - if only due to the demographic of the users.
Surely the vocal cords and larynx of an adult woman are on average larger than those of a 10yo boy?
There should exist frequencies impossible to reach for anyone but post-pubescent men.
Of course that would make it teen-age verification at best.