Over at the Journal Science is a story on how quiet sounds at low frequencies can affect your hearing. The research focuses on sounds which are (theoretically) above the 20Hz "low end" frequency threshold of normal human hearing, but tend to be either perceived as extremely quiet, or be completely inaudible.
In this experiment researchers exposed volunteers to 90 seconds of low frequency sound (30Hz), and discovered associated effects on the physiology of the ear for several minutes. Quoting one of the researchers, Markus Drexl:
The changes aren’t directly indicative of hearing loss, but they do mean that the ear may be temporarily more prone to damage after being exposed to low-frequency sounds, Drexl explains. “Even though we haven’t shown it yet, there’s a definite possibility that if you’re exposed to low-frequency sounds for a longer time, it might have a permanent effect,” Drexl adds.
Some newspapers have run with this speculation and produced articles on how wind farms may cause hearing loss.
The original paper is published in the Royal Society Open Science Journal, and a PDF is available for download.
(Score: 1) by katterjohn on Sunday October 05 2014, @07:38AM
I don't follow the "theoretically" part. Is this supposed to mean that there can be sounds that are theoretically above 20Hz, but which are not actually above 20Hz (whatever that means)?
Or perhaps it was supposed to prefix '"low end" frequency threshold', meaning that it's the threshold that is theoretical? I'm not sure that would be accurate either.
I've studied my fair share of math and physics (although not acoustics in particular), so I'm wondering if I'm missing something important or if this is just a superfluous interjection of "theoretical" which occasionally appear around science-related articles.
(Score: 3, Funny) by aristarchus on Sunday October 05 2014, @08:59AM
"Theoretically"= PulseAudio! Yes, as you feared, this is another tentacle of SystemD! More prone to damage after exposure: that sounds like binary log files to me! /And does this mean that whole "Brown Note" thing is still just an urban legend?
(Score: 2) by Tork on Sunday October 05 2014, @10:12AM
🏳️🌈 Proud Ally 🏳️🌈
(Score: 2) by wonkey_monkey on Sunday October 05 2014, @10:37AM
I think it's meant to mean that the 20Hz lower threshold is not a hard limit, but an approximate generalisation across the species.
Sounds like this are theoretically above the threshold, but the threshold itself is arbitrary, so... in answer to your question, I don't know.
systemd is Roko's Basilisk
(Score: 0) by Anonymous Coward on Sunday October 05 2014, @10:19PM
lalalalalalala so... in answer to your question, I don't know.
+5 Great reply
(Score: 3, Informative) by tonyPick on Sunday October 05 2014, @12:06PM
Hum. I wrote that bit of the summary badly didn't I?
How about "The research focuses on sounds which are above 20Hz. This frequency is at the "low end" of normal human hearing, however the minimum pressure at which sounds can be heard is frequency dependent, and as a result these sounds tend to be either perceived as extremely quiet, or be completely inaudible. More information on this is available at the Wikipedia Psychoacoustics page [wikipedia.org].
this is just a superfluous interjection of "theoretical" which occasionally appear around science-related articles
It might be a practical application of that. Theoretically speaking. :)
(Score: 2) by darkfeline on Sunday October 05 2014, @04:31PM
It is worded a bit poorly, but if you read the entire sentence the intent should be obvious
>The research focuses on sounds which are (theoretically) above the 20Hz "low end" frequency threshold of normal human hearing, but tend to be either perceived as extremely quiet, or be completely inaudible.
20Hz is the low end of what humans can hear, and the research focuses on sounds that are above that, but tend to be perceived as extremely quiet or completely inaudible. Humans can hear frequencies above 20Hz. Theoretically.
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(Score: 3, Interesting) by TheLink on Sunday October 05 2014, @10:16AM
But in the study, after 90 seconds of the low-frequency sound, participants’ SOAEs started oscillating, becoming alternately stronger and weaker.
Wouldn't the change they are observing be due to this: https://en.wikipedia.org/wiki/Acoustic_reflex [wikipedia.org] https://en.wikipedia.org/wiki/Tensor_tympani_muscle [wikipedia.org]
What I wonder is if you can damage your hearing by chewing or even snoring while having your ears plugged (with ear plugs, fingers or other) . The sound sure seems louder with the plugs inserted.
(Score: 2) by Nerdfest on Sunday October 05 2014, @03:27PM
I wear ear plugs on my motorcycle, and in-ear buds while working to block nose while allowing music volume to be kept low. Both of these seem to really accentuate low-frequency noises that are transmitted through the body. I seem to be losing some high frequency hearing despite my best efforts. I wonder if this is related. It could just be getting older, but it would be nice to know.
(Score: 4, Interesting) by SlimmPickens on Sunday October 05 2014, @11:36AM
What about people that produce or mix club music (but aren't performing much) or people that play church organs? Pretty much all my music has 20-30 Hz content, I've been listening to techno (on 20 Hz capable systems) for 20+ years and yet my hearing is excellent (can hear very quiet sounds, 22-18,000 Hz at reasonable SPL, no tinnitus).
Pretty sure the general consensus is that volume matters, not the frequency.
(Score: 2) by kaszz on Sunday October 05 2014, @12:04PM
There's probably noise all the way from 30 Hz down to 0 Hz.
(Score: 2) by Bot on Monday October 06 2014, @05:40PM
I concur that with attention you don't lose much hearing, anyway you hear mostly bass drum impulses at 20hz, and AFAIK with no subwoofer the 20hz band is rendered at least 10db less than other frequencies even in big studio monitors. Maybe the research done on continuous background tones messes up with the ear self calibration more than hurting it but I sure do not want to test it out.
Account abandoned.
(Score: 1) by fatuous looser on Sunday October 05 2014, @05:11PM
Maybe someone can help me out with that diagram of the inner ear. I feel a little thickheaded at not being able to figure it out for myself. What is the fang-like object pointing downward below the eardrum? & please don't tell me it's a "canine tooth" LOL
(Score: 0) by Anonymous Coward on Sunday October 05 2014, @08:09PM
Stirrup, I think.
(Score: 1) by fatuous looser on Monday October 06 2014, @01:52AM
You're obviously just trying to stirrup a response from me. But what's even funnier is that gratuitous walrus tusk, mischievously thrown in to see if anyone's paying attention.
(Score: 0) by Vokbain on Monday October 06 2014, @08:10AM
Somewhere, Bryan Cranston's head just exploded.
(Score: 0) by Anonymous Coward on Monday October 06 2014, @08:37AM
It is interesting how those news papers immediately think of wind farms.
In my experience, the main source of annoying low-frequency noise are construction machines. And the most annoying thing is that those noises carry on over quite a distance; even buildings in between don't seem to effectively stop them.
And yes, they don't appear to be loud (given the distance at which you still hear them, they probably are, however), but they are extremely nasty.