The HD 2020 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.

Advantages of the HD 2020 Sound level calibrator are:
• The 1000Hz frequency allows calibrating sound level meters with any weighting (LIN, A, B,...), without applying any correction factor.
• The calibration sound pressure level is independent of atmospheric pressure: you don't need to adjust the value according to static pressure over a wide range of values.
• The HD 2020 calibrator can be conveniently used both in laboratory and in the field. The 114 dB sound level allows performing calibrations even in high background noise environments.
• Its simplicity of use allows the use even by unskilled personnel.
• The presence of the LCD helps you through the steps of setting the calibrator, signal the end of the span and allows you to check the status of the battery.

ACOUSTIC CALIBRATOR
1. ON-OFF key: turns on and off the instrument. When you turn the instrument on, the display will switch on about three seconds later.
2. SETUP key: allows you to enter and scroll menu. To exit, press it repeatedly until you go back to the standard screen.
3. Display. When you turn the instrument on, it shows all segments on, and then the sound pressure level (94 or 114dB) will appear in standard view.
4. Calibrator cavity for conventional ½ inch microphones.
5. Down: in standard mode, it selects 94dB and 114dB pressure levels alternately. In menu mode, it decreases the current value.
6. Up: in standard mode, it selects 94dB and 114dB pressure levels alternately. In menu mode, it increases the current value.
7. Battery lid.