Sound Level Meter Data Logger with type 1 microphone | NSRT_mk3

306.00 $ USD

An optional Audio USB Interface is available for this product.

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The NSRT_mk3 is a sound level meter datalogger with a type 1 digital MEMS microphone, an accurate date/time clock, and a non-volatile 128 Mb recording memory with a fast USB download. Now featuring a dust-protected microphone.

In stock (can be backordered)

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Product Description

The Sound Level Meter Data Logger NSRT_mk3 is the third generation of Convergence Instrument’s smart integrating sound-level meter/datalogger. It includes a type 1 digital MEMS microphone, an accurate date/time clock, and a non-volatile 128 Mb recording memory with a fast USB download.

Running on battery, it can record sound pressure levels for a week. Connected to an external USB charger it can record for months. Its very small size allows it to be attached to or embedded within the monitored equipment.

Every Sound Level Meter Data Logger NSRT mk3 purchased is provided with an Individual Manufacturer’s Certificate of Calibration from Convergence Instruments. This all-digital design includes the A, C and Z weighting curves. It is enclosed in a completely weatherproof casing which is designed for indoors and outdoors applications. Its highly sensitive Type 1 MEMS microphone has a noise floor of 30 dB-A, and is ultra stable with time and temperature variations. The software includes an oscilloscope and spectrum analyzer features, as well as email alarms.

Mounting Base and Tripod Adapter are included.

Sound Level Meter Data Logger NSRT_mk3 Applications

  • Sound level and acoustic dose measurement and recording.
  • Monitoring of safe working conditions.
  • Activity detection and logging.
  • Long-term measurement and recording of acoustic levels for environmental impact studies.
  • Specially designed for long-term outdoors applications.
  • Type I precision
  • A, C and Z weighting curves.
  • Integrating Sound-Level Meter, records L-max, L-min and Leq levels.
  • Log interval adjustable from 125 ms (8 points per second) up to hours.
  • Individual Manufacturer’s Certificate of Calibration from Convergence Instrument provided with every instrument purchased.
  • Digital very sensitive MEMS microphone (30 dBA typical noise floor)
  • Completely sealed weatherproof enclosure designed for outdoors applications. Now includes an ePTFE membrane that seals the microphone against dust and water.
  • All-digital design.
  • Ultra-stable sensitivity (field recalibration is easily done, but seldom required)
  • Very low sensitivity variation due to temperature changes
  • Very low sensitivity to vibrations
  • Software function calculates global Leq and/or dose, according to ISO and OSHA methods.
  • Adjustable response time.
  • Preprogrammed recording start date/time.
  • Integrated oscilloscope function that can show the acoustic signal in real time.
  • Integrated spectral analyzer function that can show the spectrum (or 3rd-octave bands) in real time.
  • Can be used as a high-quality USB digital microphone
  • Allows the observation of recorded levels while the recording is ongoing.
  • Works standalone, or USB connected.
  • Long life internal rechargeable battery that recharges from USB and most USB chargers.
  • Can be field-calibrated.
  • Observes and records 100% of the acoustic signal (no missed samples).
  • Editable individual custom ID for easier instrument management.
  • All settings are stored in non-volatile memory. So the instrument will regain full functionality from hard-reset or battery loss.


Weight 0.35 lbs
Dimensions 7.25 × 3.25 × 1.5 in

20 Hz to 20 kHz

Microphone Sensor

Digital MEMs

Precision Class

Complies with the precision requirements of IEC61672-2002 Type I

Saturation Level (typical @ 1 kHz)

120 dB-A, 120 dB-C, 120 dB-Z

Temperature Error

Better than 0.6 dB (-20°C < T < 60°C)

Sensitivity to Vibrations

60 dBSPL/g (20 dB lower than typical measurement microphone)

Weighting Curve

dB-A, dB-C, dB-Z

Noise-Floor (Typical)

30 dB-A, 46 dB-C, 52 dB-Z

Recording Resolution

0.1 dB

Duty Rate of Signal Capture

100% – No Missed Samples

Min Log Interval

125 ms (8 points of Lmin, Lmax and LEQ per second)

Real-Time Spectral Display

2048-Point Power Spectrum – dB or Lin Scale.


Field-calibrated using a 1/2" calibrator



Internal Battery Type

Integral Li-Poly – USB-Rechargeable

Recharge Time

2 h 30 (Typical)

Internal Battery Autonomy (Full-Charge)

7 days while recording

Internal Battery Life

> 300 Charge/Discharge Cycles

Temperature Range

-20°C to 60°C (-4°F to 140°F)

Recording Memory

Non-Volatile Flash Memory

Recording Memory Capacity (RT128 Model)

128 Mb, Ex: can continuously record Lmax, Lmin and Leq levels at 1s intervals for 32 days, or 10s intervals for 320 days.

Recording/Erasure Cycles

Greater than 100 000

Data Retention

Greater than 20 Years


19 mm x 42 mm x 160 mm – (0.75” x 1.65” x 6.25”)


100 g (0.1 lbs)


Weather-proof enclosure

Microphone Dust Protection

Expanded polytetrafluoroethylene (ePTFE) dust and water barrier

NSRT_mk3 NSRTW_mk3 (Wireless)
Precision Class Type I Type I
Rechargeable Battery Autonomy 7 Days (Recording) 7 Days (Recording)
Connectivity USB USB & wiFi
Email Alarm Functions No Yes
Weighting Curves A, C, Z A, C, Z
Recording of Acoustic Signal Yes Yes
Attachment System Wall or Tripod Mountable Wall or Tripod Mountable
Weight 3.3 oz
93 g
3.3 oz
93 g
Memory 128 Mb 128 Mb
Data Non-Volatile Non-Volatile
Settings Non-Volatile Non-Volatile
Software Instrument-Manager
Timer Yes Yes
FFT Resolution (For Real-Time Display Only, Not Recording) 1024 points 1024 points
Software Description Importance Download
Instrument Manager Universal Installer Instrument Management Software Essential Install BEFORE connecting the instrument
Noise Sentry RT Community Noise Metrics Installer An application to calculate various noise metrics, such as CNEL, LDEN… and many others Optional
Instrument Disk Recorder An application to stream to disk the acoustic signal Optional
NSRT AutoCalc An application to calculate and automatically export standard metrics to Excel (LEQ, Lmin, Lmax, percentiles...etc.) Optional
NSRT Directivity An application to show the frequency response and directivity pattern Optional

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