Sell a fraction of tickets at higher prices (perhaps via auction) ahead of time, and sell the rest at the door. Scalpers cannot pretend to be multiple people if they have to enter the venue and pay.
The known-price door tickets set a bound on the value of advance tickets, with the latter having a premium for certainty of getting in. Younger people with less money will place less value on certainty (they can wait in line at another concert).
Scalpers can still buy advance tickets and scalp them, but they have reduced pricing power because buyers might rather take a chance at $50 door tickets than pay $500 to a scalper. And there may be less bad press about tickets costing $500 if most of them are sold at the door for $50.
sell low price vouchers, require ID for them, make them refundable in 90+ days or in person with ID only
set up a membership/trust/reputation system for fans and/or frequent venue goers (eg. locals), and if they actually show up to gigs, then you can reduce the refund wait time for them, etc.
The known-price door tickets set a bound on the value of advance tickets, with the latter having a premium for certainty of getting in. Younger people with less money will place less value on certainty (they can wait in line at another concert).
Scalpers can still buy advance tickets and scalp them, but they have reduced pricing power because buyers might rather take a chance at $50 door tickets than pay $500 to a scalper. And there may be less bad press about tickets costing $500 if most of them are sold at the door for $50.