Occupational Health Test Solution

Noise Exposure at Work

The XL2 Sound Level Meter provides the dedicated solution for occupational noise monitoring. All measurement data is stored on the SD card. Simultaneously the XL2 may record a wav-file.

The event recorder functionality triggers the measurement by programmable level thresholds or manually by the external input key pad. An additional scheduler triggers measurements at pre-determined times. The Remote Measurement option extends the XL2 for storing data directly on a connected computer and the Extended Acoustic Pack offers linear wav-file recording.


  • Measure noise exposure at work according to directive 2003/10/EC and ISO 9612
  • Follow the Control of Noise at Work Regulations 2005
  • Confirm compliance with health standards ISO 1999
  • Selecting the right hearing protection to prevent hearing loss at work


  • Handheld and compact design for field applications
  • Calibrated acoustic measurement system
  • Improved efficiency with dedicated measurement profiles and appending test results to previous data records
  • Automated sound level documentation and high resolution wav-file recording in 24 Bit / 48 kHz format to SD Card

XL2 Measurement Functions

XL2 with M4260 Measurement Microphone
Stack Light

Sound Pressure Level SPL

for noise at work monitoring
  • LAeq (averaged sound level with A-weighting)
  • LCpeak (peak sound level with C-weighting)

Both levels are measured simultaneously, thus providing the base for comparison with the action limits listed below. The real-time spectrum analyzer provides detailed results about any annoying frequency band or exact frequency.

The optional Extended Acoustic Pack offers further noise levels as required:
  • Sound Exposure Level LAE
  • LCeq - LAeq

Stack Light

The XL2 forms with the Stack Light a stand alone solution for noise at work monitoring applications. The Stack Light is controlled by the XL2. It alarms at exceeding sound levels, thus employees near the test station are notified immediately.

Noise Exposure Level LEX,8h

The Noise at Work Directive 2003/10/EC reduces the risk of hearing damage for employees. The action limits are

  LEX,8h LCpeak  Action
Lower limit value 80 dB(A) 135 dB recommend wearing hearing protectors
Upper limit value 85 dB(A) 137 dB hearing protectors must be worn and noise level reduced as possible
Exposure limit 87 dB(A) 140 dB employee with hearing protectors shall never exceed this limits

Determination of Noise Exposure Level LEX,8h:

  • At steady noise (applies for LAS deviation is < 5 dB)
    Measure the LAeq over a few minutes, the resulting LAeq represents the noise exposure level of the complete 8 hours period LEX,8h = LAeq. The following formula applies for a daily exposure time ≠ 8 hours:
    LEX,8h = LAeq + 10 x log ( T / 8 hours )

  • At steady noise with stepwise level variations
    (applies for steady noise at clearly distinguishable levels)
    Measure the LAeq at the different levels and note the corresponding exposure time. Enter all data in the NTi Audio noise exposure level post processing form; the LEX,8h will be calculated and displayed.

  • At varying noise levels:
    LEX,8h = LAeq measured for 8 hours


Exel Set for Noise Measurements


  • XL2オーディオ&アコースティックアナライザ
  • M4260 測定用マイクロホン
  • XL2用ASDケーブル
  • XL2用ACアダプタ
  • Exel システムケース



with additional features for sound level logging


for accurate noise measurements


for visual (pre-) warning indication


Reference Customers

AAC Acoustique Audio Conseil • Acoustic Dynamics Pty Ltd • Adnitt Acoustic Services • Adrian James Acoustics Ltd • Apex Acoustics • Arup Acoustics • Basler Verkehrsbetriebe • Bugano AG • Cerami & Associates • Danish Army Engineers • DFS Deutsche Flugsicherung GmbH • Flughafen Köln/Bonn • Genesis Integration • Gertsen & Olufsen AS • Goodhand Acoustics Ltd • Hewlett Packard Company • iAcoustics • Instrulabs Pty. Ltd. • JTA Health Safety & Nois Pty Ltd • Lindt und Sprüngli Schweiz AG • Mach Acoustics • Merck • MYG-Marion Acoustics • ÖBB, Austria • Pacific Environment • Philip Dunbavin Acoustics • Renzo Tonin & Associates • SBB Telecom, Switzerland • Société de Transport de Montréal • Umweltamt Stadt Chemnitz • Umweltmesstechnik Bayreuth • Vanguardia Consulting • Wiener Festwochen • Wiener Linien GmbH & CO KG • WSDG, Switzerland

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NTi Audioへのお問い合わせ

NTi Audio Contact Japan  
岡安 達也



Customer Comments

I Love It
“The XL2 is currently the world’s most versatile hand-held acoustic and audio analyser. I can do so much with it, and just love it! And in many ways, the associated Data Explorer software is much more versatile and easier to use than other leading industry equivalents.”
Glenn Leembruggen,
Acoustic Directions, Australia

Better price with more versatility
"I am happy that you keep on developing new applications and uses for the XL2, it is quite a convenient and powerful tool. In my opinion it is a serious competition for the traditional sound level meters at a better price and with more versatility. The Type Approval is an important step forward in the acceptation of the system; even in situations where type approval is not really needed, it helps avoiding discussions on the validity of the measurements."
Ben Kok, www.benkok.com, Netherlands

XL2 Data Explorer Software
"With regards to analyzing the recorded noise data: The idea of hovering over the marker text or locking the set of them is absolutely brilliant for assessing the tonality of a marked section. I could not have thought of a better system. And the percentile calculator letting you choose any marker, Filter band or Level parameter is just perfect."
Jason Dixon, www.instrulabs.com.au, Australia