As far as affordable on-ear headphones go, it may seem iGrados are the de facto choice. Not so; their open-back design means they leak noise badly, making them an inconsiderate choice for commuters.
That's where closed-back headphones like the Sennheiser HD 218s come in. They may lack the spaciousness of open models, but at least you won't fall out with a stranger on the train.
What they offer is a weighty, clear and refined delivery that'll flatter heavily compressed music and tame a bright-sounding MP3 player.
We would like greater detail and attack, and bass – though deep – could be tighter, but they're good by the standards of affordable closed-back cans.