'The ambience is really hot,' Canadian DJ Felix-Antoine Leroux said as he surveyed the crowd. 'It's just too bad about the sound.'

The show was the third of The Indie Ones, a series of free concerts organised by composer and musician Kung Chi-shing for the Heritage X Art X Design festival.

Each show received noise complaints and police orders to turn the volume down.

'The police came three or four times during the first one,' Kung said. 'Every time they came we turned it down. At the end we weren't even using a mike for the drum set, but the police still wanted to give us a summons. We had to talk them out of it.

'The funny thing is that I got government support for the shows. They support outdoor music but don't help you deal with the noise issues.'

In response, Kung has banded together with several other musicians, concert promoters and music journalists to launch 'Make Some Noise', a campaign they hope will persuade the government to relax its noise restrictions on music performances - an issue that touches on Hong Kong's support for arts and culture as well as the way it deals with noise pollution.

In recent years, almost every major music event in the city has been affected by noise complaints. Last October, the multimedia arts festival Clockenflap, which was held in a garden in Cyberport, had so much trouble with noise complaints that organisers have decided to move most of this year's festival indoors.

'We had noise complaints during the sound check from one person stating that the music was drowning out their TV,' festival co-director Mike Hill said.

For Kung, having a concert outdoors brings music to those who might not otherwise seek it out. Every month, he invites musicians of various genres to play free outdoor shows as part of his Street Music Series, which takes the Hong Kong Arts Centre in Wan Chai outside.

'I'm really only interested in doing free outdoor concerts,' he said. 'Hong Kong streets are very exciting. The energy is incredible. Last year we did a street performance of opera. Puccini in the middle of Wan Chai - it was an amazing experience.'

For many, though, adding an opera singer's falsetto to the city's near-constant din of jackhammers and roaring buses could be hard to take. More than 10,000 noise complaints are made each year, the Environmental Protection Department says, about 40 per cent of which have to do with neighbourhood or domestic noise. For concerts, the noise ordinance sets a limit of 10 decibels above the prevailing background noise.

'What bothers me a lot is that, if a resident doesn't like the music, they'll call the police,' Kung said. 'It's an emotional reaction, they just don't like the music. If there's construction going on, they wouldn't call the police, they just accept it as part of Hong Kong life.'

Prolonged exposure to noise pollution could impair hearing, cause stress and increase blood pressure, said Lawal Marafa, a professor of geography at Chinese University who is doing research on the city's sound environment.

But exactly what constitutes noise was subjective, he said. 'It's a matter of perception. If you listen to reggae, you might love it, but somebody else will say: 'What the hell is that?''

Kung said: 'Music is positive and lots of people like it, but nobody likes the sound of a construction drill except the person making money from it. Noise pollution in Hong Kong is like air pollution - it's very serious, but we're not dealing with it enough.

'We need to separate what is acceptable noise from unacceptable noise. Once we do that, we can move forward.'

The Environmental Protection Department says the noise created by traffic on a busy street is 70 decibels; the noise from a pile driver can reach well over 110 decibels. Construction projects can obtain special permits that exempt them from noise limits for a specific period of time.

Kung said that, given the benefits of outdoor music, concert organisers should be able to apply for a similar exemption.

'One of the hardest things for us is knowing that we have a licence to do an event, but that does not protect us from being shut down if people complain,' said Hill, the Clockenflap organiser. 'That is not a sustainable approach, so a noise permit could help with this. However, I doubt if any of the current venues would be able to sustain such a policy, as the residents would protest against every application.'

The government should identify spaces in the city that were ideal for outdoor concerts and make it easier to book them, such as the newly reclaimed Central waterfront or the future West Kowloon Cultural District, Kung said.

He said the government should streamline the outdoor concert permit application process. At present, 'you have to talk to four different government departments just to arrange one show'.

Concert promoter Nimal Jayawardena was so frustrated with the bureaucracy that he left. From 2003 to 2006, he organised Rockit, an annual music festival in Victoria Park. For the last show, Jayawardena had to hire noise monitors to keep noise below the government-imposed 80 decibel limit.

'Our baseline costs were too high, and the baseline costs were, unfortunately, appeasing all of the licensing issues, paying for security, paying for noise monitoring,' he said.

'I think in other countries, city councils would have provided the venue for free because they know it's good for them. It promotes their city on a cultural basis, and makes it a lot more appealing for investors in other industries. But we didn't get that.'

Jayawardena now organises the Macau International Music and Art festival. 'I don't have to go through the licensing process in Macau, whereas in Hong Kong, I may have to spend six months worrying about it,' he said. 'We stopped doing [Rockit] in 2006 because there was just too much red tape and it became too much of a hassle.'

When asked whether he thought 'Make Some Noise' would succeed in changing the government's attitude towards music, Jayawardena was blunt: 'No. Good luck to them for trying but you need a big movement to change legislation.'

But Kung said the success of his Street Music Series, which has just won Arts Development Council funding for another year, was proof of a growing appetite for outdoor music. He has won the support of Wan Chai district councillor Yolanda Ng Yuen-ting, who is considering ways to bring the series to other parts of Wan Chai.

'Even if you don't have money, you can enjoy music outdoors,' Ng said. 'On the street, there's more freedom, it's more romantic. Anywhere can be a good spot for outdoor music - it just depends on how we communicate with the residents.'