Why Do Electric Vehicles Make Noise?
3 Answers
Electric vehicles make noise because pure electric vehicles are required to emit such warning sounds when driving at low speeds. The reasons for the noise are: The vast majority of pure electric vehicles produce a peculiar "humming" sound when driving at very low speeds. This sound is completely inaudible inside the car and can only be heard outside, specifically near the front of the vehicle. Moreover, as soon as the speed increases, this sound immediately disappears. The source of the sound: In fact, this sound is not from the motor but is artificially generated. The sound does not originate from the motor but is emitted by a specialized speaker. This sound is called the low-speed warning tone. Currently, the low-speed warning tone is a national standard in the pure electric vehicle industry, and almost all pure electric vehicles must emit such a warning sound when driving at low speeds.
As a car reviewer who frequently tests electric vehicles, I've found that the sounds in EVs mainly come from these sources: The motor operating sound is the most fundamental - that high-pitched 'whirring' noise during acceleration is like turning up a hair dryer's speed, which is actually the physical phenomenon of electromagnetic field energy conversion. Interestingly, engineers now actively tune this sound to enhance driver engagement. Another often overlooked source is the thermal management system - when the battery coolant circulates and the compressor operates, it produces a 'humming' sound in the garage similar to a refrigerator starting up. What surprised me most is how much more noticeable tire noise becomes in EVs - without engine sound masking, even the air tearing sound from tire tread patterns becomes clearly audible at speeds above 80 km/h.
Last time I took my daughter in a ride-hailing car, she suddenly asked, 'Daddy, why is this car singing?'—she was referring to the pedestrian warning sound. Now, EU regulations mandate that electric vehicles must emit sounds when traveling below 30 km/h, which has helped many elderly people in our neighborhood avoid accidents. These synthetic sound effects are not malfunctions; for example, the Nissan Leaf simulates the sound of an airplane taking off, while BYD uses piano chords. However, some car enthusiasts dangerously remove the warning horn fuse, which can result in penalty points if caught by traffic police. Here’s a fun fact: the external warning sound and internal alert system are two separate systems—the 'beeping' sound when the charging gun isn’t properly connected belongs to the latter.
