Casella CEL CEL-63X - Manual (Page 75)

CEL-63x Environmental & Occupational Noise Meter
75 Casella CEL
10 Additional information
The following additional information relates to testing under IEC 61672-1:2002
section 9.3 of the standard.
1. Reference sound pressure level
The reference sound pressure level can be selected to 94 dB or 114 dB.
2. Reference level range
The CEL-63x instrument has a single measurement range of 0 dB to 140 dB.
3. Microphone reference point
The microphone reference point is the centre of the microphone‟s diaphragm.
The 0° reference direction is perpendicular to the microphone‟s diaphragm.
4. Acoustical frequency response testing
Table 3 shows the pressure to free-field correction data for the CEL-251
microphone used for periodic testing.
Table 3. Pressure to 0° free-field corrections
Frequency
Without wind
screen
With wind
screen
Without wind
screen
With wind
screen
Expanded
uncertainty of
corrections at 95 %
probability (k=2)
Bruel & Kjear 4226
calibrator
Bruel & Kjear UA0033
electrostatic actuator
Hz dB dB dB dB dB
31.5 -0.1 -0.1 -0.1 -0.1 0.2
63 -0.2 -0.2 -0.2 -0.2 0.2
125 -0.2 -0.2 -0.2 -0.2 0.2
250 -0.2 -0.2 -0.2 -0.2 0.2
500 -0.2 -0.2 -0.2 -0.2 0.2
1000 0 0.1 0 0.1 0.2
2000 0.3 0.7 0.3 0.7 0.3
4000 0.7 1.4 0.8 1.5 0.3
8000 2.8 2.5 3.1 2.8 0.4
12500 5.3 4.1 6.2 5.0 0.6
16000 6.4 4.5 7.8 5.9 0.6