The sound quality of vehicle interior noise: A challenge for the NVH-engineers
Abstract and Figures
The sound quality of vehicle interior noise has become a very important task for the acoustic engineers since more than 20 years. As vehicles become more and more quiet, the customer's sensitiveness for the acoustical comfort increases. On the one hand, no disturbing noises should be heard and on the other hand, the perceived sound quality, for example from the powertrain, should fulfill the expectations of the listener with respect to the sound design. The development of a good sound quality is in conflict with other targets. The development time of a new car has to be reduced and the production costs have to be lower, the total weight of the car should not increase – without any negative influence on the sound quality. For the acoustical engineer it becomes important to know what kind of tools are available to measure, to analyse and to describe sound quality on the one hand and how to improve it on the other hand. Reference to this paper should be made as follows: Genuit, K. (2004) 'The sound quality of vehicle interior noise: a challenge for the NVH-engineers', Int. J. Vehicle Noise and Vibration, Vol. 1, Nos. 1/2, pp.158–168. Biographical notes: Dr.-Ing. Klaus Genuit was born in Düsseldorf in 1952. He studied electronic engineering from 1971 to 1976 and economics until 1979 at the Technical University of Aachen. Concurrently, he attended the institute of 'Elektrische Nachrichtentechnik' to investigate different psychoacoustic effects of human hearing. He received his Ph.D. in 1984 based on work with 'A Model for Description of the External-Ear-Transfer-Function'. For the next two years, he led the psychoacoustic working group dealing with binaural signal processing, speech intelligibility, hearing aids, and telephone systems at this institute. In cooperation with Daimler Benz (Stuttgart), he developed a new, improved artificial head measurement system for the diagnosis and analysis of sound. In 1986 he founded the company HEAD acoustics GmbH which is a leading contributor in areas of binaural signal processing, analysis, auralization of virtual environments, NVH analysis, and telecommunication measurements. HEAD acoustics now has about 100 employees worldwide.
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... NVH (Noise, Vibration, and Harshness) has increasingly become a key indicator of automotive quality, directly impacting passenger comfort [1,2]. Prolonged exposure to a poor NVH environment can adversely affect the physical and mental well-being of occupants, leading to driver fatigue, decreased concentration, and even contributing to traffic safety incidents. ...
... where F is the force exerted on the substrate by the incident bending wave, F′ is the reaction force exerted by the locally resonant unit on the substrate, 1 M is the mass When the bending wave at frequency ω propagates through the unit cell substrate, the equilibrium equations for the substrate and the locally resonant unit can be established in accordance with Newton's second law, as presented in Equations (1) and (2). ...
To reduce the low-frequency noise inside automobiles, a lightweight plate-type locally resonant acoustic metamaterial (LRAM) is proposed. The design method for the low-frequency bending wave bandgap of the LRAM panel was derived. Prototype LRAM panels were fabricated and tested, and the effectiveness of the bandgap design was verified by measuring the vibration transmission characteristics of the steel panels with the installed LRAM. Based on the bandgap design method, the influence of geometric and material parameters on the bandgap of the LRAM panel was investigated. The LRAM panel was installed on the inner side of the tailgate of a traditional SUV, which effectively reduced the low-frequency noise (around 34 Hz) during acceleration and constant-speed driving, improving the subjective perception of the low-frequency noise from “very unsatisfactory” to “basically satisfactory”. Furthermore, the noise reduction performance of the LRAM panel was compared with that of traditional damping panels. It was found that, with a similar installation area and lighter weight than the traditional damping panels, the LRAM panel still achieved significantly better low-frequency noise reduction, exhibiting the advantages of lightweight, superior low-frequency performance, designable bandgap and shape, and high environmental reliability, which suggests its great potential for low-frequency noise reduction in vehicles.
... This sound source identification process is essential for evaluating the in-cabin acoustic environment and highlighting potential refinement opportunities in vehicle development. The results align with earlier research that established engine noise, tire noise, and wind noise as the primary acoustic contributors in vehicles [22,23]. ...
This paper evaluated the acoustic characteristics of electric vehicles (EVs) using both psychoacoustic and soundscape methodologies by analyzing three key psychoacoustic parameters: loudness, roughness, and sharpness. Through correlation analysis between perceived values and objective parameters, we identified specific sound sources requiring improvement, including vehicle body acoustics, wheel noise, and acceleration-related sounds. The relationship between comfort perception and acoustic parameters showed varying correlations: loudness (0.0411), roughness (2.3452), and sharpness (0.9821). Notably, the overall correlation coefficient of 0.5 suggests that psychoacoustic parameters alone cannot fully explain human comfort perception in EVs. The analysis of sound propagation revealed elevated vibration levels specifically in the driver’s seat area compared to other vehicle regions, identifying key targets for improvement. The research identified significant acoustic events at three key frequencies (50 Hz, 250 Hz, and 450 Hz), requiring in-depth analysis to determine their sources and understand their effects on the vehicle’s NVH characteristics. The study successfully validated its results by demonstrating that a combined approach using both psychoacoustic and soundscape parameters provides a more comprehensive understanding of passenger acoustic perception. This integrated methodology effectively identified specific areas needing acoustic refinement, including: frame vibration noise during rough road operation; tire-generated noise; and acceleration-related sound emissions.
... The vehicle's holistic sound quality strongly influences the quality and comfort perception of the passengers [2]. In addition to aerodynamic and tire noise, tonal powertrain noise can significantly impact the interior sound quality, thus playing an important role in the vehicle development process. ...
Tonal powertrain noise can have a strong negative impact on passengers’ quality and comfort perception in the interior of electric vehicles. Therefore, in the vehicle development process, the assessment of the perceptibility of tonal powertrain noise is essential. As wind and tire noise can possibly mask tonal noises, engineers use modern masking models to determine the masking threshold of tonal powertrain noise from vehicle interior measurements. In the presently used method, the masking threshold is mostly generated with torque-free deceleration measurements. However, the influence of torque on masking tire noise must be considered. As this requires time-consuming and costly road measurements, an extension of the method is being developed, which will also enable the use of roller dynamometer measurements for the assessment. For the extension of the method, however, the influence of the torque must also be considered. This paper presents a novel calculation method that quantifies the influence of torque on the masking threshold and converts masking thresholds from an arbitrary torque level to another. By identifying the frequency and speed range that is mainly affected by the torque-dependent tire noise, a regression model with respect to the tractive force on the tires can be used to calculate a torque-dependent correction factor. The developed method can significantly improve the validity of masking thresholds and quantitatively, the method generalizes well across different vehicle segments. The error can be reduced to below 2 dB above 2000 rpm and to below 1 dB above 4000 rpm. By using this method, more valid target level settings for tonal powertrain noise can be derived.
... Klaus Genuit [30], 2004: Klaus, put all general information about the sound quality. Starting with meaning, definition and listing of influencing factors: physical sound feeling, psychoacoustic perception and psychological evaluation. ...
Customer comfort in terms of NVH is a tangible and in-tangible effect. NVH is directly and indirectly connected to the psychoacoustics of human beings and lives. As a part of the advanced NVH analysis, the effects of noise have been studied in terms of psychoacoustic parameters such as loudness, sharpness, roughness, fluctuation strength, tonality, etc. Car door or door assembly is an integral part of the car or vehicle. The door is softly and flexibly connected to the main body of the vehicle; it protects passengers from weather effects and accidental impacts. Because of the inherent flexibility of the door, its flexible connections, sharp - transient closing, and vehicle operational excitations, the door assembly is one of the main sources of noise and vibration in vehicles. It is a prime requirement to understand the NVH effect of doors on vehicles, its analysis and ways of improvement. To understand the current status of the basic and advanced NVH analysis of the door, an extensive survey and in detail study was conducted. The main focus is given on technical papers published related to noise/ sound quality (SQ) during the last two decades, i.e., between 1999 – 2022. Total 31 technical papers were scrutinized and summarized in different categories. Broadly divided into: the number of papers published each year, Number of papers on types of SQ assessment, and the number of papers discussed SQ parameters. This study of these 31 papers published between 1999 – 2022 has given a ready reference for the work done on sound quality, mainly related to the vehicle and its door NVH. The total number of parameters considered by different researchers and approaches used by them to assess the psychoacoustic parameters of noise/ sound. Finally, these parameters and their level help to determine the quality of the sound produced or generated by any source.
... Among many products, the automobile has been the subject of much research [4][5][6][7]. Eyesight, hearing, touch, and smell are the most important sensory information in automobiles, and sound is one of them [8]. Many studies have been conducted to improve the value of automobiles through sound. ...
To improve product value, research has been conducted on the sound of automobiles. However, studies of perception, including sound, may overestimate the contribution of sound because each perception is treated as an independent object of study. In this study, we clarified the influence of sound on attractiveness in the form of an overarching study of each perception and confirmed the contribution of hearing. A covariance structure analysis of the results of an online survey on the presentation of each perceptual information about automobiles revealed that hearing is the second most important factor for automobile attractiveness after sight.
... The quality and comfort perception in vehicles is strongly influenced by the overall sound quality of the vehicle [1]. Besides aerodynamic and tire noise, tonal powertrain noise plays an important role, as it can have a strong negative impact on sound quality. ...
Tonal powertrain noise can have a strong negative impact on vehicle sound quality. Therefore, an assessment of the perceptibility of tonal noise with respect to masking noise is essential for the vehicle development process. In electric vehicles, due to the missing masking by the combustion engine, new methods are required for this purpose. In this study, listening tests were conducted to determine the masking threshold in the electric vehicle interior for various driving speeds (30 km/h, 60 km/h, and 90 km/h) with an Adaptive-Forced-Choice method. The novelty of this study is that it used vehicle interior noise as a masker, compared to broadband or narrowband white and pink noises. It could be shown that the masking threshold in electric vehicles strongly depends on the driving speed, and the investigated interior noise mainly affects frequencies up to 6400 Hz in this speed range. For frequencies greater than 6400 Hz, the masking noise has no significant effect on perceptibility of tonal noise in the investigated vehicle, and only the subjects’ individual absolute threshold of hearing is relevant. Additionally, a strong variation in the masking threshold between the subjects was found for high frequencies. With these results, methods that estimate masking thresholds in electric vehicles can be improved. Furthermore, threshold targets can be adjusted for different customer groups.
... Automotive industry has been transitioning to provide robust, integrated electric powertrain solutions. The development of new electric drive units (EDUs) has been accompanied with challenges associated with noise, vibration, and harshness (NVH) refinement as well as durability and its implications on energy efficiency [2,3]. In the absence of internal combustion (IC) engine noise, gear whine noise emitted from the transmission unit becomes perceptible, especially to passengers [4]. ...
An integrated gear tribodynamics model is proposed for the study of EV powertrains’ performance. The model considers the transient effects of lubrication regimes, non-Newtonian shear thinning, inlet shear heating, deformation states of asperities in mixed regime of lubrication and contact temperature using a set of analytical routines, which are computationally efficient. The proposed gear tribodynamics model provides a breakdown of the interdependency of these attributes and studies their impact on the performance of gear contacts. The results indicate that up to 30% of the contact load can be carried by asperities, of which 80% undergo elastoplastic deformation. In addition, the contribution of lubricant to contact stiffness can be greater than that of surface asperities by an order of magnitude.
This study explores the implementation and effectiveness of smartphone-based active sound design (ASD) in enhancing the engine sound characteristics of vehicles. Traditionally confined to high-end automotive applications, ASD technology utilizes built-in audio systems to improve the auditory experience inside vehicles. This research extends the utility of ASD to standard production vehicles through integration with smartphones, leveraging Bluetooth connectivity for CAN-BUS data, such as engine speed and accelerator pedal sensitivity. The smartphone-based ASD system was implemented in a 6-cylinder gasoline engine sport sedan. Through driving tests, the synthesized engine sound was evaluated alongside real engine sound and artificial sound output, comparing both the smartphone-based ASD system and the conventional car audio-based system. Experimental results indicate that the smartphone-based ASD effectively emulates the sound enhancement capabilities of traditional systems, with minimal discrepancies in performance. This study confirms the potential of integrating ASD technology with consumer smartphones, offering a scalable and accessible approach to enhancing vehicle engine sounds. This expands the application scope of ASD and fosters innovation in automotive sound design.
Application of a New Hearing Model for Determining the Sound Quality of Sound Events
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A special calibratable Artificial-Head-Measurement-System for subjective and objective Classification of Noise
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