I have an old pair of AKG 240 DFs. I mainly bought them because of their IRT compliance, and the price was right.
When I first put them on I was disappointed. They're very flat in their response unlike HiFi phones. However I quickly
grew to absolutely love them, even before they were properly broken in. AKGs take a while. I'd buy AKG again, but
would take a closer look these days because AKG too has jumped on the artist-endorsed bandwagon.