NTi Audio
Noise Level Measurement Solutions for Vehicle Noise

Vehicle Noise Test Solution

The XL2 Sound Level Meter provides the dedicated solution for vehicle noise monitoring of cars and motorcycles at the roadside. All measurement data is stored on the SD card. Simultaneously the XL2 may record a wav-file for documentation. The event recorder functionality triggers the measurement by programmable level thresholds.


  • Authorities and police inspectors measuring exhaust noise level of stationary power-driven road vehicles according to ISO 5130, EU directive 70/157/EEC and §29 StVZO
  • Annual inspection and survey of road vehicles
  • Type approval of road vehicles


  • Simple operation by one person
  • Calibrated sound level meter with class 1 frequency response
    according to IEC 61672
  • Complete measurement kit including tripod and tape
  • Improved efficiency by dedicated measurements profiles
  • Automated sound level documentation and wav-file logging

XL2 Measurement Functions

XL2 with M4260 Measurement Microphone

Noise Level SPL

Measuring the following parameters:
  • LAFmax
    (maximum noise level with A-weighting)
  • LAeq
    (averaged noise level for environmental noise verification)

How to measure?

  • The environmental noise LAeq shall be at least 10 dB below the measured A-weighted exhaust noise level.
  • Position the measurement microphone directed towards the exhaust pipe at a distance of 0.5 m at a 45° angle in the same height; the height shall be minimum 0.2 m above ground.
  • Connect the XL2 Analyzer with the 5 m ASD cable to the measurement microphone.
  • Start the XL2 with the measurement profile ISO 5130.
  • Increase the engine speed gradually from idle to the measurement rpm according the table below.
  • Start the measurement.
  • Hold the measurement rpm for one second and release the throttle control rapidly, thus the engine speed returns to idle.
  • The measurement stops automatically after the entire deceleration period.
  • Repeat the measurement until LAFmax is within 2 dB for three consecutive measurements.
  • The final result LAFmax is calculated as average of these 3 measurement results.

Rated engine speed Measurement rpm Application
< 5000 rpm 75% of rated rpm road vehicles having at
least four wheels
5000 - 7500 rpm 3750 rpm any road vehicles
> 7500 rpm 50% of rated rpm any road vehicles

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 Type Approval Certificate

Order Information

Exel Set for Noise Measurements

Exel Kit for Vehicle Noise Inspection

  • XL2 Sound Level Meter
  • M2230 Measurement Microphone
  • ASD Cable for XL2
  • Measurement Tape
  • Tripod as Microphone Stand
  • Mains Power Adapter
  • Exel System Case

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 • 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

more ...



Contact NTi Audio

NTI Americas Inc.
Tigard, Oregon
Thomas E. Mintner
+1 503 684 7050

Related Products

Links to Functions

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