I used this video. The Hz value is displayed throughout, then just pause the video at the exact point where you either hear or don't. Much easier to note down the results that way.
Edit: Just for reference; my results:
Yamaha HS7: 115 Hz – 12000 Hz
Swans M10: 44 Hz – 12000 Hz
Audio-Technica ATH-M50: 20 Hz – 11000 Hz
Audio-Technica ATH-M50x: 20 Hz – 13200 Hz
Nocs NS200: 20 Hz – 12500 Hz
Tested the Nocs just for fun since they are my 'throw in a bag' iPhone cans. I was surprised by the result and it shows doing your research even before buying cheaper gadgets/equipment pays off in the end.