Voltcraft slc 100 sound level calibrator voltcraft slc 100 the voltcraft slc 100 sound level calibrator allows the simple alignment of sound level measuring devices and for testing measuring accuracy the calibrator generates a 1khz sinusoidal sound signal with a switchable sound level of 94 or 114db microphones with a diameter of 12 7mm 0 5in can be inserted in the calibration chamber the specified accuracies are obtained at an atmospheric pressure of 1013hpa an ambient temperature of 2