Printed with standard PLA settings, no supports (3d Model should already be correctly oriented in the 3mf file).
For your convenience I added the FreeCAD source file for easy width adjustment for different headbands.
The author remixed this model.
Original headphone rest was too wide for the Beyerdynamic MMX300 and the sidewalls not high enough, allowing the headphone to wobble around way too much for my taste.