A preliminary NASA study has discovered that people find the noise of drones more annoying than that of ground vehicles, even when the sounds are the same volume.
“We didn’t go into this test thinking there would be this significant difference,” says study coauthor Andrew Christian of NASA’s Langley Research Center, Virginia.
It is almost unfortunate the research has turned up this difference in annoyance levels, he adds, as its purpose was merely to prove that Langley’s acoustics research facilities could contribute to NASA’s wider efforts to study drones.
Nonetheless, the results indicate the extra irritation the 38 subjects experienced when listening to drone noises was as if a car were suddenly twice as close as it had been before.
It isn’t yet clear why drones sound so annoying. Participants didn’t know they were listening to drones and were unaware of the study’s purpose. All they knew was that they were hearing sounds related to “the future of transportation”, and Christian says only an expert or enthusiast could identify drones by sound alone.
Loitering in the street
One reason for the difference might relate to how slowly most commercially available drones move. A drone takes a lot longer to pass by than a car travelling down a residential street, he says, and a common complaint was how the drone sounds seemed to loiter.
“That could be a big part of it.”
If so, this might offer hope to Amazon, as the commercial drones included in the study are slower than those the company is developing, which are planned to reach about 95 kilometres per hour. “Our drones fly at a high altitude, well above people and structures,” says an Amazon spokesperson. The company is also working on making them quieter.
However, Christian points out that simply making drones “only as noisy” as delivery trucks would still mean they are more annoying, meaning companies may need to find ways to make their drones significantly quieter than ground vehicles.
His hope is that NASA can help companies solve the problem before the inevitable complaints begin, perhaps by creating noise-aware systems that allow a drone to detect how loud it is, how near it is to people and how annoyed they are likely to be, and then modify its flight path accordingly.
The full 21-page study can be downloaded here.
Source: New Scientist
There are other reasons for the increased the annoyance factor with UAV’s.
1. This is a new noise in our environment. Wonder what people would have said 100 years ago with the difference between horse shoes against pavement and early automobiles.
2, The loiter time of the noise as mentioned in the article
3. The location, being above our head instead of being at street level.
4. Awareness of what the noise might indicate – e.g.; Some one is spying on me.
38 subjects is enough to show a trend, next step is to identify the reasons for this difference in awareness. Would also be interesting to see if the awareness changes with time.
I do agree that creating quieter UAV’s is an important design consideration moving forward. Working to achieve a quieter urban environment is a worth goal.
Niel