Dancing to loud music in open spaces has been a popular way for many middle-aged and elderly Chinese people to relax and exercise. But public dancing has long been complained about because of the noise it makes.

Recently, with the help of a new device, people living near Gumei Population Cultural Park in Shanghai can now better enjoy themselves in public dancing without causing trouble for others with the loud music.

Set in a white box, the device is an amplifier that can send sound in a certain direction. Using new technology, the device controls the sound in a fan-shaped area in front of the speaker. People outside the area can hardly hear any sound.

"The device is age-friendly and it's easy to use," said Li Honglin from the company that made the device. The device is locked when not in use and the dancers take turns to keep the key.

Zhang Fengling, who lives in a community next to the park, said she's glad she can now open her windows in the evening.

Gu Xinzhen, 92, who has been dancing in the park for over ten years, said the music from the new speaker is not as loud as before, which makes dancing a little less fun, but she is glad to do something for a better living environment.

Five public dancing locations in the city have also used the device. What's more, in Suzhou, Jiangsu Province, over 1,000 public dancing locations have used similar technology. "The technology will be introduced to more places," Li said.