Sound Level Meter Acoustical Calibrator 94dB & 114dB output levels for 1 inch and 1/2 inch mic

All sound meters drift with time and require periodic recalibration, some models have an internal oscillator that enables you to adjust the signal and correct the reading but this doesn't take into account, the microphone. In order to adjust to adjust the entire system including microphone you need an accoustical calibrator like ND-9.

It has two output levels of 94 dB and 114 dB. The calibrator generates these fixed sound level signals for calibration of sound level meters. This model works with any digital sound level meter. The unit ships with a ½" adaptor installed to accommodate sound meters and microphones with 1" or 1/2" microsphone.

Effect of Atmospheric Pressure and Temperature: Most calibrators including ND-9 are affected by altitude. To correct for atmospheric pressure in areas of high altitude the transducer diaphragm within the calibrator creates the sound as it vibrates against the air. When the air is thinner (at higher elevations) a lower sound level is produced.

ND-9 is calibrated to produce 94dB at sea level. When the unit is operated above se level a slightly lover sound level is emitted depending on altitude. For each 2000ft of elevation sea ND-9 produces 0.1dB less than the 94dB rating.

Applications:
Sensitivity calibration for microphones. Suitable for acoustics field and laboratory use

Specifications
Output Sound Level: 94db & 114db
Accuracy: ±0.3db(20°C, 760mm Hg)
Frequency: 1000±0.1%Hz (allows calibration with A,B,C or D weighting networks or linear)
Temp. range: -10~50°C (14~122 °F)
Storage (with battery removed) -40~65°C (-40 ~ 149 °F)
Extremely low influence of static pressure
Temp.coefficient : 0 ~ 0.01dB/°C
Power Supply: 9v Battery
Battery life approx.100 hours
Size and Weight: 48x48x138mm , 250g