RHA is releasing a new IEM, the T20, with a brand new type of dynamic transducer, appropriately named the 'DualCoil' driver. Most dynamic driver has one diaphragm driven by one voice coil. Even the Dual-Dynamic-Matrix driver we have first seen on Radius a few years ago still uses two diaphragms with two independent voice coil to form a single drivers assembly. RHA's DualCoil driver however utilizes just one diaphragm, but driven by two voice coil simultaneously, one for upper frequency and one for lower frequency.
Kudos to RHA for being a new innovation to the IEM world.