This is a pair of JVC Xtreme Xplosives earphones. As depicted above, the main driver enclosure is larger than the average earphone's because- you guessed it- it houses a larger driver for some incredible audio experience. The manufacturer also claims the XX has some of the best bass on board. Not quite.
The bigger enclosure there means if you don't have them sitting in your ears snugly, they'll fall out due to the lash of gravity (yes, it's that dramatic). The bigger drivers are laid to waste simply because they aren't enclosed. Behind the XX brace there, the drivers are actually exposed so this means your earphones are leaking music while in use. It cuts both ways too- extraneous noise would leak into your music so you could still hear the outside world when you are supposed to be shut out entirely in your music haven. This also affects the bass response severely. In fact, there's hardly any extra bass to be heard. Come to think of it, it's akin to an open back amp with a small driver- lots of clarity but lacking in depth, everything sounds too treble-inclined.