EN-5
•
Reference conditions:
Type of the acoustic field: Free
Reference sound pressure level: 94.0dB (related to 20
µ
Pa)
Reference level range: 60 to 120dB
Reference frequency: 1000Hz
Reference temperature: +23
℃
Reference relative humidity: 50%RH
Reference static pressure: 101.325 kPa
Reference incidence direction: Perpendicular to the front of the microphone
diaphragm.
•
Calibration: Acoustic using calibrator ISO-TECH SLC 1356, B&K 4231 or equivalent.
Calibration check frequency is 1000Hz.
Nominal calibration level for the free field: 94.1dB
Nominal calibration level for the diffuse field: 94.0dB
•
Frequency for acoustic testing: 8000Hz.
•
Warm-up time:
≦
2min
•
Sampling interval: Bar graph indication
→
125 ms approx.
Numeric indication
→
1 sec approx.
•
Microphone equivalent electrical impedance (electrical input device) : Replace
the microphone capsule with a series capacitance of 27pF +/- 3pF
Microphone:
•
Model: MC-21
•
Nominal diameter: 1/2 inch electret condenser type
•
Sensitivity: -37dB (0dB = 1V/Pa)
•
Frequency response: 31.5Hz to 8000Hz
•
Capacitance: 27pF
•
Reference direction and position: Perpendicular to the front of the microphone
diaphragm at its geometric centre.
•
Maximum input sound level: 131dB at microphone for no damage.
•
Operating temperature: -10°C to +50°C
•
Temperature coefficient: Approx. 0.008dB/°C at 1000Hz
•
Dimensions: 13.2dia x 14mm
