Used LEWITT LCT 540 Condenser Microphone

To measure the self-noise of the LCT 540 S, Lewitt built a unique device. It's ten times more massive than conventional ones, weighing over 9,900 lb. in total. This amount of mass will dampen frequencies up to a 1/10,000th of their sound pressure. The frequency range from 20Hz to 20kHz is dampened by 60dB, up to 80dB on the higher frequencies. Every single LCT 540 S undergoes a series of measurements followed by adjustment of the polarization voltage to achieve the same sensitivity in every LCT.