20NFR was designed for applications where true full-range frequency response from one driver is required. From low  to up to 17kHz, this driver truly delivers that. With additional DSP, the driver can be used from about 60Hz up. We have developed very lightweight foam surround material. This material is our preference anywhere where we are designing larger cone excursions, yet lightweight piston is required. It delivers excellent acoustical properties without the mass penalties.The magnetic circuit was designed around neodymium slug magnets, with u-cup style steel. The circuit delivers very high performance in very small and lightweight form factor.