Audeze LCD-2 planar magnetic headphone Circumaura - open style, magnetic planar type transducer Frequency response: 5 Hz - 20 KHz, usable high-frequency extension of 50 KHz Total harmonic distortion (THD): Less than 1% throughout entire frequency range Impedance: 60 Ohms, purely resistive Cable: single-ended, 0.25-Inch TRS to 2x4-pin mini XLR, length: 2.5 m or 8.2 ft