HD2020 – Class 1 sound level calibrator The HD2020 sound level calibrator is a portable, battery operated sound source, suitable for sound level meters (portable and laboratory) and acoustic stations. It allows calibrating ½” microphones with mechanical dimensions compliant with IEC 61094-1 (“Measurement microphones. Part 1: Specifications for laboratory standard microphones”) and IEC 61094-4 (“Measurement microphones. Part 4: Specifications for working standard microphones”). The calibration pressure levels of 94dB and 114dB can be selected by the keypad. The 1000 Hz frequency cannot be changed. If the microphone is absent or not inserted correctly into the calibrator cavity, the sound level will blink on the display. To conserve battery life, the instrument is provided with an automatic power off function: if you leave the instrument on with open cavity, it switches off automatically after 30 seconds. If the cavity is closed and the microphone is inserted, the instrument switches off 5 minutes after turning on, provided that you don’t press any key. The calibrator display shows calibration pressure level, battery life, current date and time. Sound level calibrator class 1 according to IEC60942:2003 with LCD display. ISO 9001 calibration report included.