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Topinst - 428 Class 2 Data-Logging Noise Dose Meter
Portable high-accuracy decibel meter with 1/1 octave band filter (optional 1/3 octave band filter upgrade) / Includes factory calibration certificate according to ISO 9001

Topinst-428 is a class 2 data-logging noise dose meter that meets IEC 60651:1979, IEC 60804:2000, IEC 61672-1:2013, ANSI S1.4-1983 and ANSI S1.43-1997 requirements. This portable high-accuracy sound level meter has a large easy-to-read illuminated LCD screen that displays the sound pressure level (SPL) numerically and graphically in real time. Thanks to octave band filtering, even the slightest difference in frequency is detected.


The handheld meter also functions as a data logger, recording measurements at an adjustable interval from 1 s ... 24 h and storing the recorded measurement data to a micro SD card memory. The SD card can be removed from the meter and inserted into the SD card reader of a PC. Alternatively, the decibel meter can be connected directly to a PC via USB. The provided PC-compatible software allows for quick and easy data analysis.


This device measures from 25 ... 136 db(A) at a frequency of 20 Hz ... 12.5 kHz. The meter features A, B, C and Z frequency weightings as well as fast, slow and impulse time weightings. The 428 decibel meter is commonly used by professionals to ensure compliance with environmental noise regulations and workplace noise permissible exposure limits.


    Class 2 Data-Logging Noise Dose Meter with Certificate 428

    • Measuring range

      25 ... 136 db(A)


      Class 2

      Frequency range

      20 Hz ... 12.5 kHz


      GB/T 3785.1-2010
      GB/T 3785.2-2010
      IEC 60651:1979
      IEC 60804:2000
      IEC 61672-1:2013
      ANSI S1.4-1983
      ANSI S1.43-1997

      Frequency analysis

      1/1 Octave band filter: 20 Hz ... 8 kHz
      1/3 Octave band filter: 20 Hz ... 12.5 kHz


      Microphone Class: 2
      Sensitivity: 40 mV/PA
      Frequency range: 20 Hz ... 12.5 kHz
      Connection: TNC
      Power supply: ICCP Standard

      Data-logging interval

      1 s ... 24 h (adjustable)

      Measuring functions

      LXY (SPL), LXeq, LXYSD, LXSEL, LXE, LXYmax, LXYmin, LXPeak, LXN

      X = Frequency weighting: A, B, C, Z
      Y = Time weighting: F, S, I
      N = Statistics in %: 1 ... 99 %

      Frequency weightings

      A, B, C, Z

      Time weightings

      Fast (F), Slow (S), Impulse (I)

      Inherent noise

      Microphone: 20 db(A), 26 db(C), 31 db(Z)
      Electronics: 14 db(A), 19 db(C), 24 db(Z)

      AD converter

      24 Bit

      Sample rate

      Standard: 48 kHz
      LN Mode: 20 ms

      Measuring display

      Bar graph


      160 x 160 pixel LCD with backlight


      4 GB Micro SD card


      USB (Memory readable via software or directly as mass storage)

      Voltage output

      AC 5V RMS
      DC 10 mV/db



      Power supply

      4 x 1.5 V AA Batteries
      12 V / 1 A Power plug
      5 V / 1 A USB

      Battery life

      Min. 10 h continuous use


      70 x 300 x 36 mm / 2.76 x 11.81 x 1.42" (W x H x D)


      Approx. 620 g / 1.4 lbs incl. batteries

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