What’s that background hum I hear?
CrowdScience
BBC
4.8 • 985 Ratings
🗓️ 6 June 2025
⏱️ 29 minutes
🧾️ Download transcript
Summary
In the dead of night at his home in Machinjiri, Malawi, CrowdScience listener John can hear a small, but persistent, hum. Whenever it’s quiet enough, the hum is there – but what’s causing it? And is John the only one who can hear it?
Reports of consistent, low-pitched noise have been popping up around the world for decades. No one knows this better than Dr Glen MacPherson, who runs the World Hum Map. He tells presenter Caroline Steel his theory for what’s behind these hums.
And Caroline does some investigating of her own. We visit the Isle of Lewis off the coast of Scotland, where residents are reporting a hum. We hear about the impact that persistent noise has on people’s lives, and find out… can Caroline hear the hum too?
We also ask why some people can hear a hum but others can’t. We head to an anechoic chamber – one of the quietest places in the world – to speak to Professor Jordan Cheer, who puts Caroline’s low-frequency hearing to the test.
From industrial activity to internally generated sounds, we sift through the noise to try and find out what could be causing listener John’s hum.
Presenter: Caroline Steel Producer: Sophie Ormiston Series Producer: Ben Motley
Transcript
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| 0:00.0 | Why do some big successful brands go bust? |
| 0:05.0 | Toast is back for a new series, taking a look at the decisions that often left investors burnt. |
| 0:11.0 | I'm Sean Farrington, a BBC business journalist. I'll be hearing about the hype. |
| 0:15.0 | They're going to do the deal that makes them the most money at that point of time. |
| 0:19.0 | And I'm picking what went wrong, talking to owners and employees to ask, what can we learn? |
| 0:25.4 | It was being undercut by similar rivals. |
| 0:28.5 | It just couldn't survive. |
| 0:30.3 | Toast. Listen first on BBC Sounds. |
| 0:36.8 | It's a very, very subordial rumbling, but not only that, it's also like somebody tapping you constantly, trying to keep your attention. |
| 0:46.5 | It's like real anxious. It's like having not butterflies in your stomach, but more like mosquitoes or murder hornets. |
| 0:54.7 | Murder hornets in your stomach, persistent tapping and a constant low rumble. |
| 1:00.6 | Sounds pretty unpleasant to me. |
| 1:02.7 | I suppose the other way I could describe it is it's sort of a droning noise like if you hear an aircraft a really long way away. |
| 1:10.2 | But it's constant. |
| 1:13.3 | You're listening to Crowd Science from the BBC World Service, the show that answers your |
| 1:17.9 | science questions. I'm Caroline Steele, and continuous noise is a reality for many, including |
| 1:24.7 | listener John, who lives in Machan Chiri, Malawi. |
| 1:31.0 | I met him in the nearby city of Blantyre to find out more. |
| 1:36.9 | My question for crowds are that I want to find out, when I woke up at night, I listen very carefully to the total quietness. Then I hear this sound. It is continuously, it's neither |
| 1:42.3 | low, no high, but this is the sound, which I'm very |
| 1:46.1 | personal about it. If John wakes up in the night, he hears a constant noise, and he wants to know, |
| 1:52.1 | what is this sound? Is it sort of like a hum? Is it like a hum? Yes, it continues hum. It's negligible. |
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