Environmental Noise Solutions

Environmental Noise Monitoring

The XL2 Sound Level Meter provides the dedicated solution for environmental noise monitoring in industry and communities. It measures levels and detailed spectral information in parallel and stores the data on an SD card for post-processing and reporting. A linear audio file (wav-file) may be recorded for detailed simultaneous analysis.

The type approved class 1 sound level meter offers a flexible handheld instrument with accurate and reliable measurements. Data recording can be scheduled to occur at pre-determined times or automatically triggered when pre-determined levels are exceeded.


  • Unattended noise monitoring stations (mobile or fixed installations)
  • Annoyance assessment of noise according to ISO 1996-2
  • Construction noise measurements meeting the Section 61 notice (UK)
  • Urban noise monitoring and noise mapping according to directive 2002/49/EC
  • Verifying boundary noise level emission


  • Handheld and compact design for field applications and stand-alone operation
  • Predefined measurement profiles simplify the measurement setup
  • Calibrated acoustic test system for traceable measurements

M2230-WP Outdoor Microphone

Outdoor Measurement Microphone
The M2230-WP is a weather-protected outdoor microphone for the XL2 Sound Level Meter. It facilitates acquisition of data in outdoor environmental noise monitoring applications. The corrosion-free polymer housing, wind screen, water-repellent membrane and bird spike provide excellent protection from rain, wind, dust and perching birds. The M2230-WP consists of an M2230 microphone fitted into a WP30 weather protection kit.


  • IEC 61672 Class 1 and ANSI S1.4 Type 1 compliant for vertical and horizontal sound incidence
  • Excellent protection from rain and dust (IP54), wind and perching birds
  • Built from corrosion-free materials
  • Removable top section for easy microphone calibration
  • Standard 3/8” tripod mount
  • Optional sturdy outdoor carrying case available

Class 1 Microphone

The outdoor microphone M2230-WP fulfills IEC 61672 Class 1 as well as the ANSI S1.4 Type 1 requirements for vertical sound incidence. For compliance with horizontal sound incidence a spectral correction is employed in the associated XL2 Sound Level Meter.

Effective outdoor protection

The 90 mm wind screen protects the M2230 measurement microphone from rain and dust while reducing wind-induced noise by approximately 15 dB. The seamless design of the water-repellent membrane under the wind screen ensures perfect protection from rain and dust.

Robust design / Easy calibration

The upper section of the weather protection kit is snap-on mounted and can thus be easily removed by hand for convenient and quick calibration of the measurement microphone.

Basic Outdoor Case

Basic Outdoor Case
The Basic Outdoor Case is a simple and efficient solution for outdoor noise monitoring. Powered either by an external mains supply or a small, high capacity battery pack the case is more than adequate for a number of days of monitoring. The robust and lightweight design protects the XL2 and accessories from a wide range of inclement weather conditions.

Product Data

Heavy Duty Outdoor Case

XL2 Outdoor Case
The heavy duty outdoor case is a professional solution for short- and medium term unattended noise monitoring. The case provides comprehensive protection against dust, water and impacts. Internal dimensions provide ample space for battery packs to power the XL2 Sound Level Meter.

Product Data

Noise Monitoring Terminal

Noise Monitoring Terminal

The weatherproof enclosure is the tailored fixed installation solution for unattended noise monitoring. The enclosure is IP66 rated, highly secure and constructed of strong, hard-wearing reinforced fiberglass.

Product Data

XL2 Measurement Functions

XL2 with M4260 Measurement Microphone

XL2 Sound Level Meter

Sound Pressure Level SPL

XL2 monitors the noise pollution to verify any annoying or excessive noise. All sound levels such as actual, Lmin, Lmax, Leq and the sound exposure level LAE are simultaneously measured and logged with frequency weighting A, C, Z and time weightings Fast, Slow and the optional Impulse.

The event recorder functionality triggers the measurement by programmable level thresholds or manually by the external input key pad. (optional with Extended Acoustic Pack).

Rating Level Lr

Assesses the annoyance at a noise source according ISO 1996-2. The rating level Lr is calculated by the noise exposure corrected with different factors for an increased annoyance as follows:

Lr = LAeq + KI + KT + KR + KS

KI Correction factor for impulses
KT Correction factor for tones and information content
KR Correction factor for the time of the day
KS Correction factor for special situations and noise sources

    These correction factors are standardized and differ between countries. The detailed FFT analysis provides the results for the KT factor.

    Percentiles (optional)

    Measures statistic sound levels in wideband and the real time spectrum 1% - 99%.

    Application Examples:
    - Road Traffic Noise
    - Industrial Noise
    - Noise Pollution Level LNP = Leq + (L10 - L90)

    Remote Measurement (optional)

    Allows querying the XL2 measurement data online via the USB interface. Thus customers may integrate the XL2 into their noise monitoring application.

    Type Approval Option

    The Type Approval Option, when installed on your XL2, upgrades the instrument to the XL2-TA, the sound level meter for certified measurements. The XL2-TA, together with the M2230 microphone and Shroud jacket, forms a type-approved sound level meter offering class 1 performance in accordance with IEC 61672:2014, IEC 61260:2014, ANSI S1.4:2014 and ANSI S1.11:2014 standard.

    Type approved sound level meter configuration:
    • XL2-TA Sound Level Meter (XL2 with Type Approval Option installed)
      • Firmware V3.11
      • Optional: Extended Acoustic Pack Option
      • Optional: XL2 Input Keypad
    • M2230 Measurement Microphone
    • Shroud MXA01

    XL2-TA Type Approval Certificate

    Local Noise Monitoring Network

    Multiple XL2 Analyzers connect with USB Device Servers via LAN or WLAN within a local network for online noise monitoring. An individual Projector Software may be started for each XL2 Analyzer, thus simultaneously displaying all XL2 screens on the PC monitor. Each XL2 Analyzer can be controlled from the host PC.

    XL2 Noise Monitoring Network

    Individual Solution programmed by Customer

    The Remote Measurement Option allows querying of the XL2 measurement data online via the USB interface. Multiple XL2 Analyzers can be implemented into a customer specific noise monitoring solution. The XL2 acts as a front end device for sound level measurements.

    More about Noise

    The word "noise" means any "unwanted sound". Environmental noise monitoring is the measurement of noise in an outdoor environment caused by transport (e.g. motor vehicles, aircrafts, and trains), industry (e.g. machines) and recreational activities (e.g. music). The laws and limits governing environmental noise monitoring differ from country to country.

    At the very least, noise may be annoying or displeasing or may disrupt the activity or balance of human or animal life, increasing levels of aggression, hypertension and stress. In the extreme, excessive levels or periods of noise can have long-term negative health effects such as hearing loss, tinnitus, sleep disturbances, a rise in blood pressure, an increase in stress and vasoconstriction, and an increased incidence of coronary artery disease. In animals, noise can increase the risk of death by altering predator or prey detection and avoidance, interfering with reproduction and navigation, and contributing to permanent hearing loss.

    Various cures are available to combat Environmental Noise; Roadway noise can be reduced by the use of noise barriers, limitation of vehicle speeds, alteration of roadway surface texture, limitation of heavy vehicles, use of traffic controls that smooth vehicle flow to reduce braking and acceleration, and tire design. Aircraft noise can be reduced by using quieter jet engines, altering flight paths and considering the time of day to benefit residents near airports. Industrial noise is addressed by redesign of industrial equipment, shock mounted assemblies and physical barriers in the workplace.

    Order Information

    Exel Set for Environmental Noise Monitoring

    Exel Kit for Environmental Noise Monitoring

    • XL2 Sound Level Meter
    • Extended Acoustic Pack for XL2
    • M2230 Measurement Microphone
    • ASD Cable for XL2
    • Mains Power Adapter
    • Exel System Case

    Optional as required:

    Weather Protection WP30

    for outdoor noise assessments

    Type Approval Option for XL2

    for type approved measurements and certification

    Precision Calibrator

    for accurate noise measurements

    Remote Measurement Option for XL2

    for querying measurement data online from the PC

    Stack Light

    for visual (pre-) warning indication

    Get more Information

    Buy at the web shop or contact NTI Americas .

    Reference Customers

    AAC Acoustique Audio Conseil • Acoustic Dynamics Pty Ltd • Adnitt Acoustic Services • Adrian James Acoustics Ltd • Agility 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 • Veale Associates Limited • Wiener Festwochen • Wiener Linien GmbH & CO KG • WSDG, Switzerland

    more ...



    Contact NTi Audio

    NTi Audio Contact Americas  
    Brian MacMillan
    +1 503 684 7050

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    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

    Very Simple to Use
    "I must say that the instrument and the software are brilliant, and very simple to use, even for an old fogey like me."
    Owen Clingan, UK

    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