Self-noise levels
The self-noise is measured with the calibration set to –26.0 dB corresponding to a microphone sensitivity of 50 mV/Pa.
For voltage input, the level 0 dB then corresponds to 1µV. Typical values for the self-noise are 5dB lower than the
values stated. The noise levels are measured without light in the display.
Noise measured with 18 pF microphone dummy and microphone preamplifier Nor1209, averaged over 30 s of measurement time:
Spectral weighting functions:
A-weighted: 13 dB
C-weighted: 15 dB
Z-normal -weighted: 25 dB
Z-wide -weighted: 45 dB
Filter bands:
1/3 oct: 0,4 Hz to 5,0 Hz:45 dB
1/3 oct: 6.3 Hz to 250 Hz: 10 dB
1/3 oct: 315 Hz to 20 kHz: 5 dB
Noise measured with Nor1225 microphone and preamplifier Nor1209, averaged over 30 s of measurement time:
Spectral weighting functions:
A-weighted: 18 dB
C-weighted: 22 dB
Z-normal -weighted: 30 dB
Z-wide -weighted: 50 dB
Filter bands:
1/3 oct: 0,4 Hz to 5,0 Hz: 45 dB
1/3 oct: 6.3 Hz to 250 Hz: 15 dB
1/3 oct: 315 Hz to 20 kHz: 10 dB
Noise measured with the input terminal on the sound level meter short-circuited to ground, averaged over 30 s of
measurement time:
Spectral weighting functions:
A-weighted: 10 dB
C-weighted: 10 dB
Z-normal -weighted: 15 dB
Z-wide -weighted: 15 dB
Filter bands:
1/3 oct: 0,4 Hz to 5,0 Hz: 0 dB
1/3 oct: 6.3 Hz to 250 Hz: 0 dB
1/3 oct: 315 Hz to 20 kHz: 7 dB