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The role of acoustic analysis in automotive NVH

  • Harmonia-BBM
  • Apr 9
  • 3 min read

Acoustic analyses are essential in NVH (Noise, Vibration, and Harshness) to understand and control the way in which sound interacts with the vehicle and its environment. In the automotive context, these analyses allow us to identify, quantify and reduce unwanted noises that can negatively impact occupant comfort, the driving experience and even the perception of vehicle quality.


As engine technology advances, other noises become more noticeable, increasing the importance of acoustic management. Acoustic analysis not only improves internal sound quality, but also helps to comply with external noise and acoustic emissions regulations.


Below are some possible acoustic analyses using the PAK system.


Analysis in octave or third octave bands

It is usually one of the first techniques used to analyze a sound signal. This analysis divides the spectrum by distributing the acoustic energy into different frequency bands, allowing the identification of critical noise bands that affect occupant comfort.


Frequency band analysis also helps adjust acoustic components, such as insulation and sound absorption, to reduce the presence of noise in specific octave ranges, such as low-frequency tire or wind noise.


Sound Power

Sound Power is the total measurement of acoustic energy emitted by a sound source in all directions. This analysis measures the total amount of sound emitted by engines, exhaust systems, and other components, helping to identify and prioritize noise sources for treatment.


Furthermore, sound power is one of the parameters that can be used to check whether the vehicle complies with regulatory standards for noise emissions, both internal and external.


Sound Intensity

Sound Intensity measures the rate of sound energy flow through an area, providing information on both the magnitude and direction of sound propagation. It is a powerful tool for accurately identifying noise sources inside and outside the vehicle, helping to isolate problems such as ventilation noise or structural vibrations.


With this analysis it is also possible to create sound intensity maps inside the vehicle cabin, allowing a detailed analysis of noise distribution and suggesting areas for intervention.


Sound Localization

Sound Localization refers to the ability to identify the exact direction and origin of a sound in a three-dimensional environment. It is an important tool for diagnosing sources of unwanted noises inside the vehicle, such as humming or grinding, which can be difficult to detect by traditional methods.


Thus, this tool acts as a facilitator for the analysis of how occupants perceive the direction and origin of noises, allowing adjustments in the construction of the vehicle to improve the perceived sound quality.


Reverberation

Reverberation is the phenomenon of sound reflection from surfaces, where sound persists in a space after the original source has ceased. Reverberation is an important metric for characterizing the internal acoustic environment of a vehicle. It is a parameter that is directly linked to the sound quality of the cabin.


Reverberation analysis demonstrates how sound reflects inside the cabin, influencing acoustic clarity and comfort. An environment with a lot of reverberation can amplify certain noises in an undesirable way.


This analysis is important for optimizing the use of acoustic materials as it helps to select and position absorbent materials that minimize internal reverberation, improving sound quality inside the vehicle.


Exterior Noise

Exterior Noise refers to the sound emitted by the vehicle that affects the external environment, including engine noise, exhaust, tires and other systems. Among the applications in NVH, it is an analysis used to comply with regulations and minimize environmental impact.


In both applications, the focus is on noise reduction, but it is also used for vehicle sound quality and perception of the outside. In electric vehicles, for example, external sound can be intentionally designed to alert pedestrians or create a unique sound signature for the brand.


Acoustic analysis plays a vital role in NVH by providing tools to identify, measure and control both internal and external noise in the vehicle. Techniques such as Octave Analysis and Sound Power help to understand the distribution and magnitude of sounds, while methods such as Sound Intensity and Sound Localization enable accurate detection of noise sources. Reverberation control ensures a comfortable environment inside the vehicle while Exterior Noise minimizes environmental impact.


These analyses help to deliver quieter, more comfortable vehicles with an optimized listening experience.


In Brazil, Harmonia-BBM is the representative of the PAK system . Count on us to learn more about our hardware and software solutions for sound quality.



 
 
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