There is a film, The Secret of Santa Vittoria. Santa Vittoria is an Italian town renowned for its vineyards. In the storyline, at some stage the residents realise that the nearby village could hear the sound of the bell in the Vittoria church and use it to mark the time of morning mass.

The mayor decides that the nearby village should pay for this privilege. The nearby village refuses. Thus, the Santa Vittoria people replace the brass clapper of the church bell with one made of cork, as a result of which the nearby village can no longer hear the bell.

Thus, I argue, bells and religious noises are not a light matter. As consulting acoustics engineers, we have had many projects in which we are required to assess noise from various religious institutions. In no particular order: church bells; the Muslim Athaan (call to prayer) broadcast up to five times a day; ‘doef doef’ music from evangelical church services; choral music from cathedrals; music from church choir practices; and amplified speech from evangelical preachers.

It happens that many metros have regulations which forbid ‘noise nuisances’ and the metros are bound to investigate if a complaint is made, even if that complaint comes from a religious group. Finding a middle ground is never easy; in Paarl, in the Western Cape, there is a church which has a clock that strikes the hour, half-hour and quarter-hour. Well, until 20 years ago, it used to, before it stopped. Recently, the new church leader had the clock repaired, which resulted in complaints from one resident. We investigated and, applying the methods of SANS 10103:2008, the South African national standard pertaining to the measurement and rating of environmental noise with respect to annoyance and to speech communication, determined that the clock strikes could be regarded by some as a noise nuisance. The church fell back on a traditional defence – the church was over 80 years old, nobody had complained – now one does complain; how reasonable is that? In the end, it was agreed that the clock mechanism would be reset so that there were no chimes after 20:00. Peace reigned. Or nearly. The bartender at the local hostelry said he now had to argue with patrons that the closing time had been reached, as there was no longer a 23:00 bell strike.

‘Doef doef’ music from evangelical church services is fairly simple to deal with. The levels are very high and the metros can threaten to remove the business permit if they do not comply.

The Muslim call to prayer is a difficult subject from a noise nuisance point of view. For over 1 000 years, Muslims have relied on the human voice to call the faithful to prayer. It is also a fact that (courtesy of a very good acoustics engineer, your servant) in all the metro noise regulations by definition, the unamplified human voice cannot be in contravention of the regulations. Thus, creches, school playgrounds, sports crowd noise . . . are exempt from regulations since they are the ‘unamplified human voice’. In most mosques, the call to prayer is not ‘unamplified’ – there is an amplifier, and this is where the rub comes in. Tempers flare. Some say that the Muslim call to prayer, the ringing of church bells, or any other call to worship, can never be regarded as noise. The fact is that it is noise. The question is: Should it be regarded as a noise nuisance?

A matter relating to the call arose regarding the Muir street mosque, in Cape Town. As a result, 567 Cape Talk Radio had an afternoon of public discussion on the subject. I called in and tried to explain the above to the presenter, who disputed what I said, didn’t allow me to respond and cut me off. What is the answer? I have no suggestions regarding the tolerance or otherwise of religious noises. It is all very well to protest against infringements of people’s rights but whose rights are more important ? How does one define noise nuisance in a metro? Ideas welcome.