Shure SE215 is actually a dynamic driver. Maybe becoz of their size that they call it Dynamic MicroDriver but it's mostly a marketing naming. There is no balance armature inside. It requires slightly more power than their brothers but it shares a similar sound except for their more warmer and more dynamic like sound. It's quite a good one indeed especially if you like shure sound.

That's call hissing. Some earphone do that regardless of their price. May i know which model you are referring to.