No, it has nothing to do with On ear or Over ear. This specification exists for both. That's not what you think.
Info:
When you put closed headphones on your ears, it's a given that there is acoustic isolation from the outside world. Professionals such as DJs can isolate themselves from the noise of the sound system. For individuals, this can be a good solution to isolate yourself at work or from the noise of your children at home. Listening is also discreet for those around you: someone can read next to you without you disturbing them.
However, an open headset provides a better listening experience. The sound is more natural and the spatial effect is improved. Therefore, if there is not too much noise around, open headphones are a good choice.
A perfect compromise between closed and open, semi-open headphones are mainly intended to hear as little outside sound as possible while preserving the width and spatialisation of the sound.
More information:
http://www.materiel.net/minisites...
Image 1:
http://www.projethomestudio.fr/wp-content...
Image 2:
http://www.journaldugeek.com/files...
Image 3:
http://img1.lesnumeriques.com/produits...
