Sound signature of Quiet Vehicles : state of the art and experience feedbacks (original) (raw)

On Adding Sound to Quiet Vehicles

Proceedings of the Human Factors and Ergonomics Society, 2008

Alternative energy vehicles such as hybrids and electric tend to run quieter than many hydrocarbon fueled vehicles. Their relative quietness could negatively affect pedestrian and driver safety because of reduced sound cues compared to louder vehicles. The present study examined preferences for sounds that might provide an acceptable auditory cue to quiet vehicles. Participants heard and then rated 18 sounds (3 variations in six categories). Each sound was displayed in conjunction with a video of a moving hybrid vehicle. The sounds of an engine, white noise, and hum sound in that order were most preferred as added sound to a quiet vehicle. Implications for adding sounds to facilitate pedestrians' detection of moving vehicles and for aiding drivers' awareness of speed are discussed.

Genuit-NoiseCon2005_A New Approach for Developing Vehicle Target Sound

Evaluating sound quality leads to difficulties. Conventional tests neglect the context-sensitivity of human perception evaluation; they only reflect artificial realities which do not correspond with perceptual authenticity. Since the subjective evaluation is influenced by different modifiers, it is necessary to extend methods in order to be able to survey and represent various objective variables as well as subjective variables sufficiently. It is known that experiments in laboratories only constitute artificial realities and disregard important parameters like context, relevance or external validity. The test design lacks the consideration of the usual interaction between the self-stimulated sound and the driver as well as the context, in which the driver experiences and evaluates the perceived sound. A 3D Sound Simulation System (H3S) has been developed for the realistic reproduction of airborne sound in driving simulators. Mobile H3S is capable of simulating a vehicle soundscape -consisting of engine sound, tire and wind noise -according to a real driving situation. A vehicle equipped with this interactive technique can be driven regularly on the road while the acoustic impression for the driver originates from a different or modified vehicle. The soundscape adapts online to changes in speed, engine rpm and load caused by the vehicle controls.

Electric and Autonomous Vehicle: from Sound Quality to Innovative Sound Design

Proceedings of the ICA congress, 2019

This study follows long-term lines of research and realizations accomplished within the frame of electric vehicle sound design. It currently deals with the most up-to-date issue addressing the near future mobility: Autonomous Drive (AD). It has been implemented in a 2-year collaboration with a french car manufacturer that deployed a high-tech demo-car where the sonic dimension was explored in a spatial and a multisensory approach. Specific hardware devices (multi-channel diffusion system) and software protocols (spatialization and vehicle data transmission) made possible the study and realization of numerous and accurate internal/external warning sounds and auditory Human-Machine Interfaces. The autonomous driving condition was especially considered as it corresponds to an unprecedented user experience in terms of human-centered process, where sounds could play a crucial role for informing and, if necessary, reassuring the driver and passengers. This paper presents a thorough analysis of the project: initial requirements and data, multidisciplinary framework, technical details, sound concepts and realization. It also opens onto reflexive and prospective considerations about the global notion of sound quality that especially look at possible forms of low-intrusiveness in sound design, and their related properties.

A New Approach for Developing Vehicle Target Sounds

Today, vehicle interior noise is an important customer satisfaction criterion. Acoustical engineers need to identify and eliminate disturbing noise components to maintain a competitive advantage. In fact, vehicle sound must be deliberately designed. This means that, to create driving satisfaction, certain noise aspects have to be emphasized and others reduced. Vehicle engineering needs to be extended to design-engineering and the exploration of preferred sounds. Furthermore, simulation of new engine sounds or even the sound of the entire vehicle at early stages in the development phase has become increasingly important. For example, different engine mounts can be virtually built in and their effects on interior sound can be examined without expensive iteration loops using physical prototypes. This article presents new tools for sound design and target sound development. In particluar, we introduce a new subject-centered method -Explorative Vehicle Evaluation (EVE), for determining target sounds.

Development of a Prediction Model of Acoustic Discomfort in Cars for Engine Idle Sounds

2011

Sound quality can be described as the relation between the perceptual reactions that reflect the customer's acceptance of a product that generates sound. Initially, A-weighted sound level was the only parameter used in the acoustic assessment. Since the 1950s, psychoacoustic investigations have contributed to enhance the correlation between hearing sensations and objective parameters that define the sound. Nowadays, the application of sound quality in product design is widely extended in the industry, being considered an important field study by the main automobile manufacturers. This aspect has become as important as other specifications that define the vehicle (design, equipment, colour, price...). Therefore, sound quality would be considered as a distinguishing factor that could contribute to the car purchase decision. This paper describes the development of a methodology to obtain a predicted model of acoustic annoyance applied to sounds of engines running on idle of compact cars, a feature that the customer can test in the car dealership in the process of purchase. Firstly, binaural recordings of eight car engines have been carried out by means of a digital artificial head placed on the seat of the driver. Main psychoacoustic parameters (level, loudness, sharpness, roughness...) were calculated. Afterwards, the design of a jury test was set up taking into account the kind of sounds to be evaluated. The recordings were presented to 12 subjects to assess the real sounds in a rate scale depending on the discomfort level perceived. The jury test was carried out in a laboratory where each subject listened to the recordings by means of headphones connected to an equalizer, making possible the reproduction of the sounds in an accurate binaural way and providing listeners with a realistic acoustic experience as if they were inside the vehicle. Finally, a model was established to predict the comfort rate for each sound using the psychoacoustic parameters as predictors.

Knowledge in Sound Design: The Silent Electric Vehicle—A Relevant Case Study

2017

This article builds on a large industry-driven sound design experiment focusing on the underexplored area of sound signature for silent electric vehicles. On the basis of some retrospective observations, and in the conceptual framework of design research, we propose a post-analysis that leads to provide insights on sound design as a discipline, considering its status, the status of its performers (sound designers), and its specific position between science and arts. The main aim of the article is to contribute to increase the general knowledge on sound design and to study it from the perspective of its principles, practices, and procedures.

Evaluation and Noise Impact of Car Audio Systems

This paper presents the effects of, and the problems caused by, high-end audio systems used in passenger cars. Two major aspects of the problem were investigated: first, what is the quality of the sound reproduction that can be achieved in the car interior, and how, and to what extent, car audio systems can contribute to the noise pollution of residential areas. Correspondingly, both the interior and the surrounding sound field of the test vehicles was investigated for various operating conditions of the car (including switched off engines), with three different kind of music pieces. In order to assess the environmental impact, the overall insertion loss of the car was measured. Standard bypass measurements were also performed to demonstrate the difference in sound levels between a standard car audio and a car equipped with a high-end audio system.. For better illustration of the growing problem, we calculated noise maps for a peaceful holiday resort too. The results have shown that currently used highend audio systems are not really appropriate for good quality sound reproduction, caused both by disadvantageous acoustic characteristics of the cavity and artificially modified transfer characteristics of the electro acoustic system. Significant exterior sound level differences were found between different audio systems, ranging up to 20 dB. Exterior noise predictions have shown that high-end systems can significantly deteriorate the noise environment, especially for quiet places in the night period.

Evaluation of independent sound zones in a car

2019

Recently sound field control techniques have been applied to vehicles that generate different sound zones in the inner space with loudspeaker arrays. A typical example in a car is to provide a driver and a passenger with different sound such as voice-guided navigation, music, or telephone voice. Acoustic contrast has been widely used as a performance index in sound field control that shows the difference between sound levels in the acoustically bright zone and the dark zone. However, these sound levels are usually measured with microphone arrays that are placed in the sound zones without the listeners. Thus these values can be different from what the listeners would have at their ears. This study compares the acoustic contrasts derived using microphone arrays with those using dummy head microphones at several positions and those using binaural microphones mounted in several subjects’ ears. From this comparison, this study attempts to propose a simple and effective evaluation method ...