Approximately 2 percent of the Dutch population are bothered by low-frequency sound, although a clear cause has never been found. Half of these people can be helped through the use of a CD with white noise, UG researchers say.
Elly Lamain has been hearing a constant humming sound in her house for years. ‘It sounds like a truck’s cooling system, or a ventilator. It keeps me up at night and has been getting worse over the years.’ Like 2 percent of the Dutch population, she suffers from what’s known as low-frequency sound, a relatively obscure problem.
When her issues just started, Lamain would occasionally talk to her neighbours about it. ‘But they would give me this pitying look, because they thought it was all in my head.’ It isn’t, she says: ‘I hear the sound in my own home, and almost nowhere else.’
She’s tried everything to get rid of the sound. ‘The first thing I did was switch off my fuse box to turn off all the electrical appliances in the house. But the sound isn’t coming from my house. I then turned to all these organisations to ask if they could track down the source of the sound. But that would cost a lot of money and there were no guaranteed results.’
STREAMER: The CD stops after a while. Unless you put in on repeat, but then there’s this annoying clicking noise
A little over a year ago, she came across an interesting solution: a CD developed by the Science LinX Beta Science Shop, which uses white noise to drown out the hum. The team, led by physicist Frits van den Berg, has been recruiting people to test the CD since 2007. Lamain applied to be a test subject.
The CD works: over the past few years, many people feel it has helped. ‘But that was just a subjective assessment’, says Zuhal Incedalci, master student of medicine. She is involved in the project. One thing that was missing was a scientific, objective foundation. This could help to market the CD to eve more people.
That foundation is now here: participants were asked to grade to which extent their use of the CD has changed the nuisance they experienced from the humming. Just over half of them said their complaints diminished. The results will soon be published in the scientific journal Applied Acoustics.
But Zuhal noticed something else. ‘People who hadn’t used the CD or who’d hardly used it, also reported their complaints diminishing. I can imagine that people eventually get used to the noise. But, Van den Berg adds, the complaints never completely go away. ‘Approximately 20 percent of participants used other tools to reduce the nuisance.’
Lamain also tried other methods. ‘The CD stops after a while. Unless you put in on repeat, but then you hear that annoying click. I now tune my radio to fall in between two stations so there’s a permanent white noise.’
The radio noise also drowns out low-frequency hums. It’s not as deep or obtrusive, which means Lamain likes it better. ‘It’s soothing. Whenever I do wake up, I just focus on it for a while and it’s like the low-frequency noise just disappears.’ But she’s happy the researchers started their study on the CD. ‘Without their research, I never would have found my own solution.’