71 headset stereo pc headset usb headset design over ear types dynamic closed transmission mode cable types of connection usb 20 usb sound mode 20 hardware type of headphones headband features in line control padded headband passive noise cancellation volume control adjustable headband function mute sound system dolby digital headphone transmission range 15 26000 hz sensitivity 113 dbmw headphone impedance 19 ohm microphone properties nois