PSYCHOACOUSTICS, SOUND QUALITY AND ELECTRIC BUSES
In layman’s terms, psychoacoustics is the bridging of the physical representation of sound and its subjective human hearing perception. Sound quality on the other hand, which is a discipline that falls within the field of psychoacoustics, defines the distinctive character of a sound other than its pitch or loudness (Dunne, 2003).
Sound quality metrics, if appropriately selected, can be used as a measure to objectively establish the comfort and refinement of a vehicle’s sound signature. Newly developed tonal metrics are especially relevant to electric vehicles where noise levels may not be excessive but may be particularly intrusive.
As an overview, this paper looks to delve into the techniques and metrics used in the assessment of tonal electric vehicle (EV) noises, and the subjective perception of their intrusive whining signatures which are typically associated with their permanent magnet synchronous motors (PMSM). It is important to note that these noises are typically profound during idle and low-speed conditions where road and wind noise levels are low.
This whitepaper will discuss:
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Electric vehicles, internal combustion engine (ICE) powertrains
and emitted noise
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Electric vehicle noise measurement techniques
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Sound quality assessment methods
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Quantifying noise and sound quality of electric vehicles
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Electric bus case study
In the automotive industry, such as the EV bus sector, sound quality measurement and assessment is neither trivial nor paralleled. Unlike those of conventional ICE vehicles, EV powertrains do not radiate broadband masking noise from their engines.
Reduced noise would appear to be a “win” for vehicle acousticians in electric bus original equipment manufacturers (OEMs). Unfortunately, the new challenge emanating from lack of broadband masking and characteristic of electric vehicle architecture is the variety of new tonal noises.
A new challenge for acoustic engineers is that components of EV powertrain noise sources emit mid to high-frequency tonal noises, also referred to as whining noise.. Vehicle passengers have become somewhat accustomed to the conventional broadband noise of ICE powertrains, whereas the whining noise of the EV powertrain is an unexpected intrusion for a vehicle widely marketed as “quiet” or “silent”.
The electric bus market has presented new technical and acoustic challenges to the market and these problems need new and innovative solutions to overcome.
Ventac is an established name in the supply of innovative and high-performance noise control solutions to the
Bus & Coach industry.
Our experience, technical knowledge, and acoustic expertise in an ever-changing industry allow us to work in partnership with our clients to quickly identify and solve their noise control problems and deliver an effective result.
Our vehicle noise control services include analysis through a Vehicle Acoustic Test Program, followed by custom solution design, manufacture, and delivery.
If you would like to learn more about noise sources within electric vehicles, how to identify and treat them efficiently, we invite you to sign up to receive this specific series of whitepapers.
Alternatively, if you would like to speak with a member of our team, please get in touch here.
