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Exterior noise


Exterior vehicle noise is tested in the development process and developed according to the acoustic perception and the desired sound of the vehicle. It is also necessary to ensure compliance with statutory standards, which may vary by vehicle and country.
For the engineering of external noise, we have developed an all-round application that efficiently supports you in your measuring tasks, across all vehicle classes and types, in real and in simulated pass-by: PAK pass-by


Standards and comfort

The assessment of vehicle exterior noise plays an increasingly important role in the field of overall vehicle acoustics. On the one hand, the legislator regulates noise emissions by means of introduced limit values; on the other hand, the increased demand for comfort on the part of motorists leads to a continuous reduction of the exterior noise level of motorized vehicles.
When it comes to the topic of external noise, users expect concrete answers for their engineering: fast, simple and efficient - both outside on the track and inside on the test bench.


Exterior noise measurements are used in homologation as well as in vehicle development and product quality assurance. PAK pass-by supports the user in the implementation of exterior noise measurements on the test track according to different standards through a user-friendly operation, efficient use of resources and hands-on processes.

The noise level of a passing vehicle is determined with two microphones at a distance of 7.5 m from the center of the road as a function of the distance travelled. The measurement result is set in relation to the respective test requirements and can now be evaluated accordingly. Measurement parameters are the noises caused by the drive (electric, hybrid, combustion) or tire rolling noises.

PAK pass-by supports you during and after the measurement with easy handling and direct further processing of the results. You will be guided intuitively through the measurement processes, can intervene in a controlling manner, measure according to the current international standards and thus objectively, verifiably and reliably.

  • UN-ECE R51.03 (car, truck, bus)
  • UN-ECE R51.02 (car, truck, bus)
  • UN-ECE R41.05 (motorcycle)
  • UN-ECE R41.04 (motorcycle)
  • UN-ECE R41.03 (motorcycle)
  • ASEP for UN-ECE R41.04 & R51.03
  • eASEP for UN-ECE R41.04 & R51.03
  • GOST 33555:2015
  • ADR 83/00
  • ABNT NBR 15145
  • KDV 1967
  • UN-ECE R138
  • US CFR40 Part 205 Subpart D
  • US CFR49 Part 571.141
  • TRIAS 30-J040-01
  • GB 1495 20XX
  • GB/T 22036-2017
  • GBT 37153
  • GB/T 18697-2002 + DIN ISO 5128 (Interior Noise)
  • NL PIEK 2010 + Quiet Truck
  • UN-ECE R117 (Tire Labeling)
  • UN-ECE R28
  • SAE J192 (Snow Mobile)
  • MOE-NOT Art. 6 (car, truck)
  • MOLIT-NOT 42-3
  • AVAS
  • Idle Noise Measurement
  • Background Noise Measurement
  • OpenHorn
  • Open pass-by Standard


With the simulated pass-by, you optimize the exterior noise in the test bench. Due to the year-round availability of the test benches and the exact reproducibility of the measurements through constant measuring conditions (temperature, wind or background noise), extensive exterior noise measurements can be carried out on the chassis dynamometer with different vehicle variants to develop a characteristic, recognizable vehicle sound and quickly carry out comparative testing for better comparability of vehicle modifications.

The simulated pass-by is a measurement method which enables an indoor typization of the vehicle according to UN ECE 51.03 Rev. 3 Supplement 4. The procedure is an important component for the achievement of objectives in the development and engineering process, in particular for the design or reduction of exterior and the subjective acoustic perception of the vehicle. High automation minimizes downtimes and optimizes the use of resources such as test benches and test equipment.


Idle noise

The idle noise measurement rounds off the PAK pass-by application as a comprehensive measurement and analysis tool in exterior noise measurement.

Standardized process steps in PAK pass-by speed up the testing and simplify the execution.


Tire correction

For further engineering in indoor homologation, the tire/road noise is decisive, as this, besides the drive train noise, represents an essential source of the pass-by noise of a vehicle. Since the approval of new vehicles focuses on low noise pollution overall, this parameter is also gaining in importance.

In addition to the signature of the tire on the roller, the signature of the tire on the real road surface is also recorded and included in the simulation to extract only the rolling component. The entire vehicle tire rolling noise can also be broken down into a rolling noise and a load noise to enable a quick "virtual" tire change on the test bench for simulated pass-by driving.

The procedure is as follows :

  • Analysis and simulation of rolling share (currently free rolling tires),
  • Analysis and simulation of load share (transmission of drive torque via the tire) and
  • Synthesis of both aspects for predicting tire / road noise using vehicle dynamics profiles. The tire / road noise is synthesized to a given driving profile on the test track of rolling and load share.


With contribution analysis, you can separate extremely quickly individual portions of external noise by using transfer path analysis methods (TPA). This allows vehicle developers to quickly pass through individual sources such as the exhaust system and thus gain valuable insights for further engineering and optimum vehicle tuning.

In a simulated pass-by measurement, the main sources are detected by local sensors (e.g. microphones). Then, for each of the remote pass-by microphones, the proportions of the sources are determined by performing an OTPA. The result is several (simulated) pass-by measurements, each representing only the share of one source.

The effective recording of noise-related data allows a cause-related representation of the correlations between source and respective contribution. In this case, the characteristic noises of individual components in the chain of action.

More about PAK pass-by...

PAK pass-by is the application for exterior noise engineering for real and simulated pass-by.