NL42 (Class 2)

The NL42 is a SLM meets the following Sound Level Meter standards: IEC 61672-1: 2013/2002 class 2, ANSI/ASA S1.4-2014/Part1 class 2, JIS C 1509-1: 2017 class 2.  The measurement functions include simultaneous measurement of the following items with selected time weighting and frequency weighting. Processing on the main channel enable Instantaneous sound pressure level, equivalent continuous sound pressure level, sound exposure level, maximum sound pressure level, minimum sound pressure level, and percentile sound levels: (0.1 to 99.9%, 0.1-increment steps, max 5 values)

In addition to main processing items, one of the following can be selected for simultaneous processing:

• C-weighted equivalent continuous sound level: LCeq
• C-weighted peak sound level: LCpeak
• Z-weighted peak sound level: LZpeak
• ｴ-time-weighted equivalent continuous sound level: LAｴeq＊2
• Maximum ｴ-time-weighted equivalent continuous sound level: LAｴmax＊2
• The power average of the maximum level of each 5 second interval: LAtm5
• The frequency weighting for the additional processing synchronizes with the frequency weighting
• of the sub-channel, so when the sub-channel has A-weighting, LAtm5 can be selected.
• When C-weighting (Z-weighting ) is selected, the additional processing LCeq and LCpeak
• (LZpeak) are selectable.

Microphone: UC52 with a sensitivity level of -33dB

Measurement range:

• A-weighting: 25 dB to 138 dB
• C-weighting: 33 dB to 138 dB
• Z-weighting: 38 dB to 138 dB
• C-weighting peak sound level: 55 dB to 141 dB
• Z-weighting peak sound level: 60 dB to 141 dB

 Inherent noise     

• A-weighting 19 dB or less
• C-weighting     27 dB or less
• Z-weighting 32 dB or less

Frequency range  20 Hz to 8 kHz

Frequency weighting  A, C, and Z

Time weighting  F (Fast) and S (Slow)

Level range  Single range (Linearity range: 113 dB)

Bar graph display range max  Max. 110 dB (20 to 130 dB)

Switching of bar graph display  Set the upper/ lower limit in 10 dB increments.

RMS detection circuit  Digital processing method

Sampling cycle  20.8 μs (Lp, Leq, LE, Lmax, Lmin, Lpeak : sampling frequency: 48 kHz) 100 ms (LN )

Calibration  Electrical calibration performed according to IEC and JIS standards, using internally generated signals: acoustic calibration performed with the NC-75.

Correction functions  Windscreen correction: Compliant with IEC 61672-1 and JIS C 1509-1 standards when the windscreen is installed.  Diffuse sound field correction: Correction of frequency characteristics in order to comply with standards (ANSI S1.4) in diffuse sound field.

Delay time  The meter can be set to start measuring a specified time (OFF, 1, 3, 5 or 10 s) after the start button has been pressed or when a user-set trigger is exceeded.

Back erase function   When the PAUSE key is pressed to pause measurement, the preceding (user selectable) 0, 1, 3 or 5 s data are excluded from processing.

Display   Backlit semitransparent color TFT LCD display WQVGA (400 x 240 dots) ＊LCD with touch panel (Capacitive Touch Panel) Numerical display update frequency: 1 s  Bar graph update frequency: 100 ms

Storage Manual   Data for measurement results are stored manually in single address increments. Number of data Internal memory: max. 1000 sets SD Card: depends on the capacity of the SD Card＊1

Storage Auto＊2 Instantaneous values (Lp mode) and processed values (Leq mode) are   stored continuously and automatically at preset intervals.

• Lp sampling cycle 100 ms, 200 ms, 1 s,
• Leq 1sLeq sampling cycle 10 s, 1, 5, 10, 15, 30 min, 1, 8, 24 h, and user selected time (up to 24 hours)
• Measurement Time 1000 h in Auto Lp storage mode, max. 100 000 addresses in Auto Leq

Data recall  Allows viewing of stored data

Setup memory      Up to five setup configurations can be saved in internal memory, for later recall Start up via file settings previously stored on SD card possible

Waveform recording＊2＊3

• File format Uncompressed waveform WAVE file
• Sampling frequency Select 48 kHz, 24 kHz or 12 kHz
• Data length Select 24 bit or 16 bit

DC output  Output DC signals using a frequency weighting characteristic selected by processing.

• Output voltage 5 V, 25 mV / dB at bar graph display full scale

AC output  Output AC signals using a frequency weighting characteristic selected by processing or by A, C, Z-weighting.

• Output voltage 1 V (rms values) at bar graph display full scale
• Comparator Turns on when the open-collector output exceeds the set value  output＊2 (max. applied voltage 24 V, max. current 60 mA, allowable dissipation 300 mW).

USB  Allows USB to be connected to a computer and recognized as a removable disk  Allows USB to be controlled via communication commands

RS-232C communication    Allows for RS-232C communication via use of a dedicated cable

Data continuous output＊2                                

• Instantaneous value Lp
• Processed value Leq, Lmax, Lmin, Lpeak

Output interval    100 ms

Power requirements Four IEC R6 (size AA) batteries (alkaline or rechargeable batteries) or external power supply

• Battery life (23 ˚C) Alkaline battery LR6 (AA): 26 h  Ni-MH secondary battery: 25 h
  • At the maximum ＊Depends on the setting
• AC adapter NC-98E
• External power voltage 5 to 7 V (rated voltage: 6 V)
• Current consumption Approximately 90 mA (normal operation, rated voltage)

Ambient conditions

• Temperature -10 to +50 ˚C
• Humidity 10 to 90 % RH (non-condensing)

Dustproof / water-resistant performance＊4              

IP code: IP54 (except for microphone) See precautions regarding waterproofing

Dimensions, weight Approx. 250 (H) x 76 (W) x 33 mm(D), approx. 400 g (with batteries)

Supplied accessories  Storage case x 1, Windscreen WS-10 x 1, Windscreen fall prevention rubber x 1 Hand strap x 1, LR6 (AA) alkaline batteries x 4, SD card 512 MB×1 (NX-42EX preinstalled model only)storage mode(depends on the capacity of the SD card)＊1