1. Introduction: The Paradox of Quietude
Electric vehicles (EVs) are changing how our cities sound. Unlike traditional petrol or diesel vehicles, EVs are much quieter—especially when idle or moving slowly. In fact, they can be up to 20 decibels quieter when stationary. At first glance, this seems like a great step towards reducing noise pollution. But the silence of EVs brings unexpected challenges.
Cities have long been shaped by the sounds of traffic. From a design perspective, noise helps people stay alert and aware of their surroundings. The sudden reduction in these familiar sounds calls for a rethinking of how we plan our cities and manage their soundscapes. The quietness might feel peaceful, but too much silence—especially when it removes important cues—can be unsettling. People rely on background noise more than they realize, for things like mental focus, navigation, and even emotional well-being. In that sense, complete silence might be just as problematic as too much noise.
EVs, although environmentally friendly in terms of sound, can create safety issues. Pedestrians, especially those who are visually impaired, often depend on the noise of approaching vehicles to stay safe. Without that familiar engine hum, EVs can seem to “sneak up” on people. Drivers also lose auditory feedback about their car’s speed and performance, which internal combustion engines naturally provided. The overall sound of city life becomes duller and less informative, which could impact our ability to stay alert, relaxed, and connected to our environment. This makes it clear that simply removing noise isn’t enough. We need to think carefully about the kinds of sounds EVs should make—not just for safety, but for maintaining a rich and healthy urban soundscape.
2. The Evolving Landscape of EV Acoustics
In the past, the sounds cars made were a result of how their engines and mechanical parts worked. The growl of a sports car or the gentle hum of a luxury car came naturally from the engine and exhaust. But with EVs, that engine sound is gone. Now, car manufacturers have to deliberately create sounds that match their brand and provide helpful feedback for drivers and pedestrians. This is a big shift. Instead of just trying to reduce noise, engineers are now designing what cars should sound like. This opens up creative opportunities. Some car brands are even working with composers (like Hans Zimmer for BMW) to craft unique, emotionally resonant sound signatures.
Since EVs don’t have the engine noise that used to cover up other sounds, things like road noise, wind, and electric motor whines become much more noticeable. That means sound engineers must work harder, not only to reduce these sounds but also to create pleasant and useful acoustic environments inside the car. One key area is called NVH—Noise, Vibration, and Harshness—which traditionally focused on removing unpleasant sounds. Now, NVH teams also need to add purposeful sounds to help with driving feedback and brand identity. Tools like Active Noise Cancellation (ANC) help by cutting down low-frequency noise inside the cabin. Engineers also study how people perceive sound (psychoacoustics) to make sure the added sounds feel natural and enjoyable. So, car sound design is no longer just about removing noise—it’s about building a complete and thoughtful sound experience.
3. Designing for Safety: Acoustic Vehicle Alerting Systems (AVAS)
One major safety concern with EVs is that they’re too quiet at low speeds. Pedestrians and cyclists—especially those with vision problems—can have trouble noticing EVs approaching. To address this, regulations now require EVs to include special sounds, called AVAS (Acoustic Vehicle Alerting Systems), when moving slowly (usually below 30 km/h). These rules were added after EVs became popular, showing how safety regulations are often reactive, coming in after new technology hits the streets. In the U.S., the National Highway Traffic Safety Administration (NHTSA) made AVAS mandatory for new EVs starting in 2020. Similar laws exist in the EU and other parts of the world.
However, just adding any sound isn’t enough. Research has shown that some EV warning sounds are hard for people to locate—especially in busy areas with multiple EVs moving around. Sounds like two-tone beeps don’t help people figure out where a car is or how many are nearby. In contrast, traditional engines naturally made complex sounds that our ears could easily track and interpret. So, it’s not just about making EVs audible—it’s about making their sound helpful. That means new AVAS systems should produce richer, more complex sounds that change with the car’s movement. Future regulations may need to go beyond basic “can you hear it?” tests and instead ask, “can you tell where it's coming from and what it’s doing?”
Currently, regulations in the U.S. and Europe specify the volume and frequency of these sounds. For example, the U.S. requires warning sounds at speeds under 30 km/h, with rules about how the sound should change when accelerating or reversing. The EU has similar guidelines, requiring EVs to produce noise from start-up to 20 km/h and when reversing. There’s also a challenge in balancing safety and noise pollution. Too loud or annoying AVAS sounds could create new urban noise problems. That’s why there are limits on volume and bans on odd or disturbing sounds. The goal is to keep people safe without turning EVs into a noisy nuisance.
Designers are now using advanced sound techniques, like simulations and user testing, to create EV sounds that are noticeable, pleasant, and informative—all at once. Finding this balance is essential for a safe and peaceful urban future.
Table 1: Global AVAS Regulatory Requirements Comparison
| Regulation/Standard Body | Effective Date (Mandatory for New Vehicles) | Speed Range for AVAS Operation | Minimum Sound Level Requirements | Maximum Sound Level Requirements | Required Sound Characteristics | Other Key Requirements |
|---|---|---|---|---|---|---|
| US NHTSA FMVSS 141 | September 2020 (Full Compliance) | < 30 km/h (18.6 mph) | Detailed SPLs across 13 bands (315-5000 Hz) for stationary, reverse, and various low speeds (e.g., 39-59 dB A-weighted) | No explicit max overall dB(A) stated, but bands have max levels implicitly | Relative volume change for acceleration/deceleration; "sameness" for same make/model | Stationary sound mandatory; Directivity measurement; Two assessment methods [26, 30] |
| EU Regulation (EU) No 540/2014 | July 2021 (All New Vehicles) | Start-up to ~20 km/h; during reversing | Continuous sound, min 56 dBA (within 2m) | 75 dBA | Continuous; indicative of vehicle behavior; similar to ICE; no pause switch | - |
| UNECE UN R138.01 | July 2019 (New Types Approved); July 2021 (All New Vehicles) | > 0 km/h up to 20 km/h (Permitted outside this range) | Min SPL defined up to 20 km/h | 75 dBA (for M1 vehicle) | Continuous; indicative of vehicle behavior; similar to ICE | No specifications for accelerated conditions; Pause function prohibition (UN R138.01 alignment) [26] |
| UNECE UN R138.02 (Proposed) | Under Review | Min sound up to 40 km/h; Prohibit AVAS operation outside 0-20 km/h | Ramped-up from > 0 km/h to 40 km/h | Ramped-up from > 0 km/h to 40 km/h | - | Optimizations for 3rd octave measurements; ISO 16254 (array microphones, Max Hold) [26] |
4. Crafting the In-Cabin Experience: Active Sound Design (ASD)
Electric vehicles are quieter than regular cars, which might seem like a good thing—but it also means drivers don’t get the usual engine sound feedback that helps them judge their speed. This can lead to drivers going faster than they realize or even making more driving mistakes. To fix this, carmakers use Active Sound Design (ASD). This system adds artificial sounds inside and outside the car, based on how fast the car is going, how hard you press the pedal, and how the vehicle is moving. These sounds help drivers better sense what the car is doing. Research shows that when realistic engine-like sounds are added, drivers are better at controlling speed and feel more connected to the car.
But ASD isn’t just about helping drivers—it also improves comfort. In EVs, removing engine noise brings out other sounds like wind, tires, and electric motor hums, which were previously masked. Some of these can be annoying, especially the high-pitched ones. To tackle this, engineers use Active Noise Cancellation (ANC)—a system that cancels out low and mid-frequency noises inside the cabin. Now that traditional engine sounds are gone, even small or high-frequency noises become more noticeable. NVH (Noise, Vibration, and Harshness) engineers have to focus on these new sounds. They carefully select materials and use advanced sound technology to create a peaceful and enjoyable cabin.
Sound in EVs is now an intentional feature, not just a by-product of the engine. Automakers are using techniques like filtering motor vibrations and changing sound based on vehicle speed or pedal input. Some brands simulate gear shifts with artificial engine sounds, while others go for futuristic sound effects. This brings up a big question: Should EVs sound like traditional cars or create an entirely new sound identity? Companies like Porsche use enhanced motor sounds, while others like BMW and Audi experiment with artistic and modern soundscapes. Drivers also have different preferences. For example, in the countryside, people might like natural and soothing sounds. In cities, a more futuristic but subtle sound works better. Women often prefer calming tones, while men may like sounds that feel more exciting. People’s choices can also depend on whether they’re used to gas-powered cars or already drive EVs.
That’s why a one-size-fits-all sound system doesn’t work anymore. The future lies in customizable sound environments, like BMW’s "My Modes," which allow drivers to pick their preferred sound style. Some experts even suggest that self-driving cars should have different sound profiles for different settings. Creating these flexible, personalized sounds involves real-time data, AI, and smart sensors to adjust the sound automatically based on location, speed, and user preferences.
5. The Brain on EVs: Cognitive and Emotional Resonance
To design effective EV sounds, it's important to understand how our brains interpret them. Psychoacoustics is the study of how people hear and respond to sound. It looks at things like how loud a sound feels, how sharp or smooth it is, and how these qualities affect our mood and awareness. Our brains are most sensitive to sounds in the 1–5 kHz range. In noisy places like cities, softer sounds can be drowned out—a problem for EV warning systems (AVAS). Since the brain actively looks for meaning in what it hears, familiar engine noises helped us sense speed and movement. EVs don’t provide those cues naturally, so synthetic sounds must be clear, easy to understand, and informative without overwhelming the driver.
The lack of engine noise can make driving feel strange or mentally tiring. Drivers might unknowingly speed or get distracted because their brains have to work harder to interpret other signals. While cutting sound can reduce stress in some situations (like turning off music when lost), in EVs, the missing helpful sounds can have the opposite effect—increasing the driver’s mental load. Studies using brain-scanning tools like EEG show that when drivers are already focused on other tasks, they become less responsive to sounds. This means EV sound design should aim to reduce the mental effort needed to understand what’s happening—helping the driver feel in control without overloading their brain.
Sounds also affect emotions. A good engine sound can excite a car enthusiast. While EVs don’t have that traditional "roar," their quietness can create a calm, smooth driving experience. This can be just as powerful emotionally, especially for drivers who value peace, sustainability, or futuristic aesthetics. People are also more open to new sound types once they get used to them. That’s why emotionally rich and unique EV sound design matters. Instead of copying traditional engine sounds, EVs can offer new types of emotional connections. For example, relaxing tones might help some drivers feel at ease, while bolder, sci-fi-style sounds may excite others. Sound personalization is becoming more important—letting each driver shape their emotional experience.
Neuroscience supports this. Certain sound qualities activate reward and motion-related parts of the brain. Tests using fMRI and EEG show that preferred sounds make brain activity last longer and feel more satisfying. Just like music with a good rhythm ("groove") makes us want to move, EV sounds that match how a car accelerates or turns can feel more natural and enjoyable. Brain studies even show that when sound and visuals are in sync, the brain can better recognize what’s happening—key for both drivers and pedestrians. This proves that well-designed sound isn’t just about being heard—it’s about being understood, felt, and remembered. By tapping into neuroscience, carmakers can design EV sounds that not only please our ears but also enhance safety, reduce stress, and build emotional connection—helping EVs stand out in both function and feeling.
Table 2: Key Psychoacoustic Parameters in EV Sound Design
| Parameter | Definition/What it Measures | Relevance to EV Sound Quality | How it's Evaluated | Key Findings/Implications for EVs |
|---|---|---|---|---|
| Loudness | Subjective perception of sound intensity | Overall perceived volume; crucial for understanding human ear's perception of sound intensity | MOSQITO software; objective data from acoustic environment | Low amplitude of vehicle background sound ensures high speech articulation; influences comfort and power perception |
| Roughness | Subjective perception of sound modulated within 15–300 Hz | Identifies unpleasant or discomforting sensations in auditory experience | MOSQITO software; objective data from acoustic environment | Correlation with comfort perception; helps identify specific noise sources needing improvement |
| Sharpness | High-frequency component of sound signal | Influences perceived clarity and tonal qualities; related to high-frequency content | MOSQITO software; objective data from acoustic environment | Correlation with comfort perception ; fundamental to governing EV sound experience; reduction improves interior sound |
6. Beyond Functionality: Brand Identity and the Future of EV Sound
Sound is becoming a powerful branding tool in electric vehicles (EVs). Known as sonic branding, this approach uses sounds—like start-up tones, acceleration cues, and notification chimes—to express a car brand’s personality. Just like logos and color schemes, sound can shape how we feel about a car. In fact, sound triggers emotions more quickly than visuals, which is why carmakers now see audio as a key part of the driving experience. With EVs being so quiet, brands have a unique chance to design custom soundscapes from scratch. This blank audio canvas allows companies to stand out in a market where looks and performance often feel similar across brands. By creating a distinct "sound identity," carmakers can build stronger emotional connections with drivers and leave a lasting impression.
Let’s explore how different car brands are doing this:
BMW IconicSounds Electric:
BMW teamed up with famous composer Hans Zimmer to create rich and expressive sounds for their electric cars. Their sound experience changes with driving modes like "Sport" or "Efficient," giving drivers emotional and dynamic feedback based on how the car is performing.
Porsche Electric Sport Sound:
Porsche focuses on keeping it real. They amplify the actual sounds made by the electric motor and transmission, filtering out unpleasant tones. This helps drivers stay connected to their car while maintaining Porsche’s legacy of performance and precision.
Hyundai N Active Sound+:
Hyundai uses detailed data like motor vibrations, speed, and pedal pressure to create engine-like sounds that feel authentic—even though they’re artificial. Their system even simulates gear shifts to give drivers a more engaging and sporty experience.
Mercedes-Benz:
Mercedes offers different sound profiles such as "Silver Waves" (space-like) and "Roaring Pulse" (deep and powerful). These sounds can be heard both inside and outside the car. While some people enjoy the futuristic feel, others still prefer the more natural motor sounds. These examples show how brands have different takes on EV audio—some aim for realism, while others embrace imagination and creativity. The big question remains: should EVs sound like the cars of the past, or explore totally new sound worlds?
Customizing the Sound of the Future
One thing is clear: sound personalization is the future. BMW’s “My Modes” is a great example—drivers can choose the sound experience that fits their mood or environment. This opens the door for adaptive soundscapes that respond to location (urban vs rural), user preferences, or even weather and time of day. For example, softer and more natural sounds may work better in peaceful rural areas, while bold, high-frequency tones might help alert pedestrians in busy cities.
Men and women may have different preferences, and EV owners may want different sound experiences than traditional car drivers. A universal sound design just isn’t enough anymore. To achieve this, automakers are exploring AI-powered sound systems that adjust audio in real time using user feedback and driving data. With tools like machine learning, sensors, and real-time sound synthesis, EVs can offer a more personalized and emotionally engaging drive for each person.
EV Sound Research in India
Indian carmakers are increasingly focusing on EV sound design to address both safety concerns and user experience. With EVs being much quieter than traditional vehicles, companies like Tata Motors and Mahindra Electric are working on developing Acoustic Vehicle Alerting Systems (AVAS) to ensure pedestrian safety, especially in India's dense urban environments where people often rely on sound for road awareness.
Tata Motors is exploring how artificial sound can be used not only to meet regulations but also to enhance brand identity and driver feedback. Mahindra, under its Born Electric initiative, is testing futuristic sound profiles that align with its premium electric vehicle vision. These efforts include both external warning sounds and interior Active Sound Design (ASD) for better speed perception and engagement. Collaborations with research bodies like ARAI are also helping define India-specific standards, ensuring that sound solutions suit local road conditions and cultural expectations.
7. Conclusion: Harmonizing Innovation and Human Experience
Electric vehicles have changed how we think about sound in cars. In the past, engine noise was just a by-product. Now, sound is a carefully designed feature that plays an important role in safety, driving feedback, brand image, and even emotional connection.
The quietness of EVs, while good for reducing noise pollution, brings unexpected problems. Pedestrians can struggle to hear them, which is why Acoustic Vehicle Alerting Systems (AVAS) were introduced. However, many of these warning sounds still lack the clarity needed to tell where the car is coming from or how fast it's going. So, more thoughtful design is needed—not just sound that’s audible, but sound that’s helpful.
Inside the car, Active Sound Design (ASD) helps replace the missing cues that drivers relied on in traditional cars. These sounds need to be meaningful—not just loud or artificial. As the car world debates whether to keep engine-like sounds or go futuristic, each brand must find the right balance that feels true to its identity.
More importantly, EV sounds must also support how our brains work. We're used to using sound to make sense of speed, surroundings, and emotion. Taking that away can increase mental load, slow reaction times, or cause discomfort. But well-designed EV sounds can reduce stress, support focus, and even trigger positive emotions—especially when they are fine-tuned for how our minds respond to rhythm, tone, and clarity.
As car brands look to the future, the focus will be on flexibility, personalization, and emotional depth. The most successful EVs won’t just be quiet—they’ll sound smart, feel right, and connect with drivers in deeply personal ways. The "silent revolution" of electric mobility is not just about less noise—it's about better sound.
Disclamier: The information provided in this blog is for general educational and informational purposes only. All opinions and interpretations expressed are based on publicly available research and current industry practices as of the time of writing. This content does not represent the official views of any automotive brand or regulatory authority. Readers are encouraged to consult official sources and experts for professional guidance. The blog does not promote any specific product, and any brand names mentioned are used for informational purposes only.
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