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Sound and Vibration Instrument Hire and Calibration

Norsonic 140 Specifications

Norsonic 140 Sound Level Meter

Nor 140   Precision Sound Level Analyser with filters, statistics and logging £ 24 a day *

Overall Performance

The Nor 140 meets the following standards set for sound level meters, 1/1-octave and 1/3 octave filters:
IEC 61672-1:2002 class 1, IEC 60651 class 1, IEC 60804 class 1, IEC 61260 class 1.

Analogue Inputs

Number of channels: 1
Input connector: 7 pin LEMO connector for Norsonic microphone systems.
Microphone : Nor 1225, 1/2", free field, 50 mV/Pa
Preamplifier : Nor 1209 (Normal) or ICP®-type by menu selection.
Preamplifier supply voltage: ±15 volt, max 3 mA
Polarisation voltage: 0 V and 200 V, selectable.
Maximum input signal: ±11 V peak
Preamplifier ICP®:
Supply current: 4 mA
Supply voltage: 24 V
Input impedance: > 100 kΩ, < 650 pF

Measurement Range:

Measurement range: 0,3 µV - 7 Vrms (10 V peak) in one range corresponding to -10 dB to 137 dB (140 dB peak) with a microphone sensitivity of 50 mV/Pa.

High pass filter

The input section is equipped with an analogue high-pass filter to reduce noise from wind or other sources with frequencies below the frequency range for measurements. The filter is switched on if the limited frequency range is selected >6.3 Hz. Filter type: 3rd order HP filter -3 dB at 3.4 Hz, Butterworth response.

Analogue to digital conversion

The analogue input signal is converted to a digital signal by a multi-range sigma-delta converter with an effective sampling frequency of 48 kHz. The anti-aliasing filter is a combination of an analogue and a digital filter.

Frequency weightings

Simultaneous measurement of A and C-weighting or A- and Z-weighting. 1/1 octave band or 1/3 octave band levels may be measured simultaneously if options providing these weightings are installed.
1/1 octave filters: 0.5 - 16000 Hz, class 1, digital IIR filters, base 10 system IEC 61260 and ANSI S1.112 0 0 4 Class 1.
1/3 octave filters: 0.4 - 20000 Hz, class 1, digital IIR filters, base 10 system IEC 61260 and ANSI S1.1120 0 4 Class 1.

Level detector

Detector type: Digital true root mean square ( RMS) detection, resolution 0.1 dB which may optionally be increased to 0.01 dB for indicated levels in the range -9.99 to 99.99 dB.
Crest factor capability: The crest factor is only limited by the peak-value of the signal.

Simultaneous measurement of the following functions:

SPL, Lmax, Lmin, Leq, LE, Lpeak, Ln (the exceedance level for F-time-weighted sound pressure level, the cumulative distribution); LeqI; LEI; Lmax5.

Indication range

Indication range The calibration of the instrument allows microphones with sensitivity in the range -84 dB to +15.9 dB relative to 1 V/Pa to be applied. The corresponding display range for the indicated sound level is -50 dB to +180 dB.

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 1 µV. Typical values for the self-noise are 5 dB lower than the values stated.
Noise measured with 18 pF microphone dummy and microphone preamplifier Nor 1209, averaged over 30 s of measurement time:
A-weighted : 13 dB
C -weighted : 15 dB
Z-weighted : 25 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 Nor 1225 microphone and preamplifier Nor 1209, averaged over 30 s of measurement time:
A-weighted : 18 dB
C -weighted : 22 dB
Z-weighted : 30 dB
1/ 3 oct: 6.3 Hz to 250 Hz: 15 dB
1/ 3 oct: 315 Hz to 20 kHz: 10 dB

Power supply

Batteries : 4 cells, IEC Lr6, AA-sized
Typical battery life time: up to 14 hours
External DC: 11-16 V. Power consumption approximately 1.2 W depending on selected modes of operation. The mains adaptor Nor 340 is recommended for use with the instrument. If the external supply falls below 9 V, the instrument will use the internal batteries if available.


The display is a monochrome, transreflective LCD graphical display with 160x240 pixels (WxH) with automatic temperature compensation for contrast and viewing angle. Pressing the light key illuminates the display. The light switches off automatically two minutes after the last operation of any key. The bargraph display covers 80 dB which may be scrolled in 10 dB steps to cover the total range.

AC output

3.5 mm stereo jack. Both channels have identical signals driven by two separate amplifiers. Load impedance shall be 16 Ω or more.
Output voltage is generated by the 48 kHz DAC based on data from DSP. Full scale on the display bargraph corresponds to 100 mV.
Output impedance: Less than 10 Ω AC-coupled 100 µF.
Gain accuracy 1 kHz: ±0.2 dB
Frequency response re. 1 kHz: ±0,5 dB for 20 Hz < f > 20 kHz.


USB interface: USB type 2.0 USB socket: B411
Serial I/O port: Rs232 port, 9600-115200 baud.
Digital inputs: 3 pc
Digital outputs: 4 pc

SD Memory Card

The instrument may use SD memory card for storing of setup information and measurement results. 1 x SD memory card included, on sale-or-return, with each instrument hired.

Data Storage

Measured data is stored in the internal memory of the sound level meter or on the SD memory card. The internal memory is of the "flash type retaining the information without battery supply. Approximately 25 Mbyte is available for the data storage which corresponds to one of the following examples:
More than 50,000 global measurements with all available global functions and statistical distribution when filters are switched off.
More than 12,500 global measurements with all available global functions and distribution when filters are switched off.
Approximately 12,500,000 samples of L(t) when only one function is logged, corresponding to more than 60 hours with a resolution of 0.1 sec.

Environmental conditions for operation

Temperature: -30 °C to +60 °C
Humidity: 5 to 90 % RH, dew point less than 40 °C
Atmospheric pressure: 50 to 108 kPa


Depth: 30 mm
Width: 75 mm
Weight incl. batteries: 410 g
Length, excl. microphone/ preamplifier : 210 mm
Length, incl. microphone/ preamplifier : 292 mm
E&OE - specifications subject to change without notice.