Electric cars don't make any noise, which is the biggest difference from cars with internal combustion engines. Because without the engine transmission, you can only hear some tire noise. So pure electric vehicles create a very quiet driving environment because it doesn't have the engine or exhaust sound like an internal combustion engine car.
It's too quiet, that's the problem. This is because pedestrians may not notice the approaching of electric vehicles when driving at low speeds. Since this is related to pedestrian safety, countries are proposing safety regulations related to electric vehicles.
In South Korea, when driving at speeds below 20 km/h, warning sounds below 75 dB must be heard from the outside. In Europe, the warning tone is up to 20 km/h and the warning tone is set to 56 dB.
This "Acoustic Vehicle Alert System" is just a security device. Because of this, manufacturers are focused on creating a unique tone that doesn't blend in with the surrounding sounds so that pedestrians can quickly tell that a vehicle is approaching.
Automakers are focusing on developing new voices for electric vehicles. This is to convey the impression of the exhaust sound emitted by the engine of the internal combustion engine to the electric vehicle.
To date, the exhaust sound of cars with internal combustion engines is considered the prerogative of a few manufacturers. Among them, Maserati's exhaust sound wave brings a unique presence that is hitherto completely different from other companies. The low to mid-range exhaust sound generated by AMG's 8-cylinder engine also has a huge fan base. Porsche's exhaust sound fascinates many people and is known as the "Porsche Note". The exhaust sound of the Lexus LFA is very famous, known as the "roar of the angels". In addition, Lamborghini's V12 sound, McLaren's V8 sound, GM and Ford's V8 sound are also distinctive.
However, as the era of electric vehicles approaches, the exhaust sound that was originally "proprietary" to some manufacturers is soon inaudible. As a result, various automakers are concentrating on developing the sound of electric vehicles. The aim is to create the sound of electric vehicles with their own characteristics.
In order to convey a feeling similar to the exhaust sound of an internal combustion engine, the most appropriate sound is delivered to the occupants taking into account various variables such as speed, motor torque and the amount of acceleration pedal operation. It is characterized by the introduction of particle synthesis methods used in the field of electronic music to create sounds that have never been heard before. Granular synthesis refers to sound synthesis technology that breaks down sounds into very small units and then combines them to create a new sound.
BMW collaborated with "master of film music" Hans Florian Zimmer, who created the films The Lion King, The Dark Knight and Interstellar. This led to the birth of the BMW Iconic Sound Electric.
Starting with BMW's flagship electric vehicle, the iX, and the sports-electric coupe i4, the iconic Sound Electric, used in a variety of vehicle models, is passed on to occupants from the moment the ignition button is pressed. Especially after setting the sport mode, if you run fast, it is characterized by a heavy and strong sound that emits a mid-bass, rather than the high-frequency sound of an electric car.
Mercedes-Benz also installed a unique sound for EQS electric vehicles. Users can choose between Silver Waves and Vivid Flux sounds, which are preferred for everyday driving. At this point, EQS produces minimal sound while driving, allowing you to feel a quiet and luxurious driving experience.
Audi also installed its own sound with the e-tron GT. To create a sound unique to electric vehicles, up to 32 sounds were synthesized, including the sound of the wind blowing through plastic pipes, the sound of wireless electric vehicles, and the sound of helicopters.
Pedestrian warnings are not uncommon and sound similar to exhaust sounds from high-performance engines. The sound transmitted to the interior of the car while driving maintains the characteristics of the electric vehicle, but also conveys the feeling of a high-performance internal combustion engine.
The Porsche Taycan is unique in both appearance and sound. The 24 Hours of Le Mans champion car, the 919 Hybrid, is characteristic of the sound it makes as it drives on the track. Unique sounds can be heard both indoors and outdoors. It's worth mentioning that the Taycan Turbo S comes standard with the Electric Sport Sound feature, which focuses on conveying the feeling of driving a Porsche rather than an electric car.
At the same time, as the electric vehicle market grows, so does the virtual sound market. According to Persistence Market Research, a U.S. market research firm, the virtual exhaust sound market will grow from about $34 billion in 2017 to $21.4 million in 2025.