http://pure.tudelft.nl/ws/files/7747083/1_s2.0_S0888327015003647_main.pdf

General framework for transfer path analysis: History, theory and classification of techniques $

Based on neural network model, a method for quantitative sound quality (SQ) evaluation of the interior noise of a pure electric vehicle (PEV) is presented in this paper The method can be divided into four steps First, the interior noises under different speeds of a PEV are collected through the interior noise test of the PEV Subsequently, one physical acoustic parameter (A-weighted sound pressure level) and six psychoacoustic parameters (loudness, fluctuation strength, tonality, roughness, articulation index, and sharpness) are applied to describe the noise samples for objective evaluation of SQ In the third step, five semantic evaluation indexes, namely, “annoying or pleasing,” “harsh or sweet,” “weak or powerful,” “promiscuous and pure,” and “unobservable or perceptible,” are proposed based on semantic differential method, which are used for subjective evaluation of SQ by jury tests Finally, the neural network model for SQ evaluation of the interior noise of the PEV is established, the SQ characteristics of the interior noise of the PEV are evaluated, as well as revealing the coefficient weight of influencing factors This model can be used for SQ prediction and evaluation of the interior noise of the PEV considering that the average error is 9%

Sound Quality Evaluation of the Interior Noise of Pure Electric Vehicle Based on Neural Network Model

A comprehensive review of tire-pavement noise: Generation mechanism, measurement methods, and quiet asphalt pavement

This study developed a method to evaluate the sound quality of the warning sound masked by background noise considering the masking effect. The warning sound of an electric vehicle is required by law for the safety of pedestrians. Therefore, the warning sound becomes an additional noise pollution source if it is designed as an annoyance. On the other hand, if the sound is designed with a low sound pressure level, pedestrians will not recognize the approach of vehicle due to background noise. To avoid nose pollution and permit the detectability of an approaching vehicle, a method for evaluating the annoyance and detectability of an electric vehicle is required. In this paper, the whine index evaluating the whine sound masked by the background was developed and used as a sound metric. This metric was employed for the development of an annoyance index and detectability index for electric vehicles.

Objective evaluation of the sound quality of the warning sound of electric vehicles with a consideration of the masking effect: Annoyance and detectability

Limited Traffic Zone (LTZ) is a planning strategy that is more and more adopted by municipalities in Europe to improve their environmental conditions. It consists in the prohibition for traditional vehicles to circulate in specific areas. Although the main aim is to tackle air pollution problems, positive effects are registered in terms of reduction of noise annoyance and in terms of improved “quality of life” if specific conditions are respected. On the other side under the drive of the global market, the number of circulating electric vehicles in urban sites is also increasing. In the next years we expect to experience a new and not well-known urban soundscape.

In this paper is presented an overview of recent urban projects and policies that deal with noise control and how these experiences will match into the next years with the sound characteristics of new electric vehicles for private and public transportation.

/pdf/electric-vehicles-and-urban-noise-control-policies-472sy4q1ax.pdf

Electric Vehicles and Urban Noise Control Policies

Electric or hybrid vehicles are very quiet at low speeds, which represents a very good opportunity to reduce traffic noise annoyance in cities. On the other hand, this may be very hazardous for vulnerable pedestrians (e.g. visually impaired people). The aim of the eVADER project is to propose solutions in order to add warning sounds to such cars, while fulfilling two contradictory goals : sounds should be detectable but should not contribute to traffic noise annoyance. Different perceptual experiments have been conducted : the first one evaluated the influence of various timbre parameters on sound detectability. It was shown that an electric vehicle equipped with one particular sound was as easily detected as a diesel one, while keeping a very low level. Then the influence of some timbre parameters (pitch and temporal modulation frequency) on the distance and speed as perceived by listeners was measured. Finally, a third experiment was devoted to the consequence on traffic noise annoyance of such warning sounds.

/pdf/detectability-and-annoyance-of-warning-sounds-for-electric-3fgg5v7ikf.pdf

Detectability and annoyance of warning sounds for electric vehicles

The eVADER project endeavors to enhance the technology of lectric-vehicles for the safety of pedestrians, especially the visually-impaired. The research presented here focused on eVADER's goal to isolate features of replacement sounds for electric-vehicles, maximizing pedestrian safety while minimizing noise pollution. It was predicted that 3 sound features (complexity, amplitude-modulation, frequency-modulation) could be the most informative to listeners, allowing for quieter emission. Sounds were synthesized using different combinations of the 3 (features) X 3 (levels). The 9 synthesized sounds were normalized (dBA), Doppler-shifted, and superimposed onto a binaural-recording of a moving electric-vehicle (prototype-sounds). Stimuli were embedded in a noisy background (traffic or traffic + rain), emulating a suburban soundscape. In this simulation, participants were virtual pedestrians, waiting to cross a street, using only sound. In a fractional, repeated measures design, 111 participants (29 visually-impaired) heard 11 stimuli (9-prototype-sounds, 1-electric-vehicle, 1-diesel) over 88 trials. Participants localized approaching cars (perpendicularly). Results indicated that detection of some prototype-sounds was equivalent to that of the diesel car. This was achieved without significantly increasing SPL. Despite normalization, detection varied among prototype-sounds via the 3 (feature) X 3 (level) combinations. This effect was magnified in noisier backgrounds. The practical and theoretical implications will be discussed.

https://hal.archives-ouvertes.fr/hal-00957765/document

Joseph Schlittenlacher

Papers

Detectability and annoyance of warning sounds for electric vehicles

eVADER: A Perceptual Approach to Finding Minimum Warning Sound Requirements for Quiet Cars.