They were listening to the imam instruct them how best to follow the Islamic holy month of daylight fasting and prayer. "Allahu akbar" (God is great) resonated several times from the archaic but functioning speakers.
Speaking in Arabic, the imam then proceeded to recite from the Quran, punctuating his sonorous speech with occasional relapses into Chinese to explain to his congregation the importance of observing Ramadan.
Then, at a sign from the imam, the assembled men stood up inside the now cramped courtyard to bow several times before dispersing to chat with friends and exchange greetings of goodwill, even taking time to mention the fighting in Iraq, a sign of pan-Islamic solidarity.
Government records shows that there are some 21 million Muslims in mainland China, mostly located in the western provinces of Gansu and Xinjiang. This figure though tells only part of the story.
The are 10 ethnic minority groups
that have long practised Islam
In effect a population count of the 10 ethnic minority groups that have traditionally practised Islam, the figure takes no account of how many of these groups' members are secular, nor how many converts there have been from among other ethnicities, including the majority Han who account for 96% of the population.
Laying down his rush mat at the back of the mosque, 23-year-old Yu Dejun is one of the uncounted.
Unlike the vast majority of the congregation whose facial features betray them as being from western China, he is clearly Han Chinese. A recent convert to Islam, this is his third Ramadan.
"I felt empty before; there was no spiritual side to me, but now I feel much happier in life," he said referring to his conversion.
A factory tradesman, Yu was first introduced to Islam by foreign students from Pakistan. Now, he says, Islam has become an integral part of his life.
"I am attracted by the idea of a greater purpose, of a God. Islam helps guide me in my life, helps me find success in what I do, and helps me think clearly to make money," Yu said, adding his own definition of Islam with Chinese characteristics.
He said his parents had no qualms about his new found faith. "They just asked me to avoid getting into trouble and losing face for the family, a condition I have always tried to abide by."
"Islam helps guide me in my life, helps me find success in what I do, and helps me think clearly
to make money"
Han Chinese Muslim
Yu's wholehearted praise in part reflects a growing interest among Chinese for some form of spirituality as the ideological moorings of Communist-era life dissolve.
In some places this emotional void has been filled by religion, both mainstream in the form of Christianity - some estimates say there are now as many as 100 million practitioners - as well as the rise of quasi-religious sects such as the Falun Gong.
Funds from Gulf
Since the late 1970s, when China reopened to the outside world, Muslims countries such as Saudi Arabia, UAE and Kuwait have been donating funds for cultural causes, including the rebuilding of mosques destroyed in the Cultural Revolution, and the establishment of Arabic learning centres.
However, despite the presence of more than 30,000 mosques (according to government statistics), it appears that Islam is not practised widely outside of its traditional base in western China.
Gulf funds in the late '70s helped
establish Arabic-learning centres
Recent press reports in China have tended to portray Islam negatively by linking it to Usama bin Ladin, violent attacks and China's own domestic problems in Xinjiang where intermittent clashes and state clampdowns have soured relationships between minority groups and Han Chinese.
But experts suggest that it is longer-term factors that account for the lack of recent converts.
"Historically, Islam has been in China since the Tang Dynasty (618-907CE) but it was never mainstream. There was never a Muslim emperor and Confucian thought was the dominant cultural force," Feng Jinyuan, an Islamic specialist with the Chinese Academy of Social Sciences, said.
Jonathon Lipman, author of several works on China's Muslims, says: "Conversions to Islam have been few and far between."
"Islam in China has
not been aggressively promoted. It is quite conservative and relies on father passing
it on to son"
Islamic Association of China
In part this appears to be because when people are looking for religion, they are looking for wider cultural associations.
The provinces of western China where Islam is prevalent also happen to be the nation's poorest, while Christianity, which is now being practised in various forms by a wide range of social classes, is linked to the West.
"At present Christianity is far more appealing because of its association with modernity, Europe and America," says Lipman.
Others, though, point to the lack of proselytising on the part of Islamic teachers.
"Islam in China has not been aggressively promoted. It is quite conservative and relies on father passing it on to son," Ma Yunfu, vice-director of the Islamic Association of China, says.
A stance that contrasts with the large numbers of Christian missionaries that travel through China, and the daily exposure to western culture that Chinese can experience in the form of books and Hollywood films that regularly touch on aspects of Christianity.
Two western provinces are home
to most of China's 21m Muslims
Given the connection between preference for a certain religion and its apparent linkages to economic success and modernity, some have suggested that the current interest in Christianity, at least among the more educated classes, is a fad that will mature with time.
"I think over the next 20 years, as the country continues to open up to religious ideas and there is greater understanding of different faiths, you will see more and more people exploring other religions besides Christianity," said one Muslim diplomat.