# Does 18hz audio ("infrasound") make people see ghosts? **URL:** \ **Category:** Factual Questions\ **Created:** [October 18, 2010, 2:57am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518 "2010-10-18T02:57:04Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![cptnred](https://avatars.discourse-cdn.com/v4/letter/c/58956e/32.png) [@cptnred](https://boards.straightdope.com/u/cptnred)\ **Post date:** [October 18, 2010, 2:57am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/1 "2010-10-18T02:57:04Z")
I just read a fascinating (if true) comment in the skeptics section of Reddit, to the effect that 18hz sound causes humans to experience hallucinations and uneasiness. According to the commenter, this explains some “ghost stories.” Here is the link: [Reddit - The heart of the internet](http://www.reddit.com/r/skeptic/comments/dseh4/easy_way_to_tell_if_your_house_is_haunted/c12jyfl) > [@](#): > > 18 Hz. Cobble together a pitch detector, any computer with a microphone or even an iPhone, and go around looking for a spot with 18 Hz at it. If the amplitude is sufficiently high you will eventually feel “uneasy” and may even see a “ghost”. > > 18 Hz is the resonant frequency of the human eye. Having it shake side to side cause the brain to go “WTF” and attempt to make sense of what is going on. This extra processing causes a mild headache in the area of the brain responsible for processing sight, which results in an odd uneasy/queasy feeling and mild visual hallucinations. > > Seriously. I live near “haunted” Salem, MA and have found the 18 Hz signal in quite a few of them. More than once I have triggered a “ghost” in myself and others by standing in a spot with a strong 18 Hz signal for a couple of minutes. > > Try it, then make sure to tell people something like “I’m the ghost whisperer”. It freaks them out every time. > > tl;dr 18Hz signal triggers feelings of being haunted. It can even trigger visions of “ghosts”. Wikipedia also seems to back this up: [Infrasound - Wikipedia](http://en.wikipedia.org/wiki/Infrasound#Human_reactions_to_infrasound) This sounds amazing, but–at least at first glance–it also sounds like a load of crap. I immediately thought to turn to you guys. So, is it for real? Could someone make a device that plays 18hz audio, carry it with them everywhere, and drive their friends crazy? ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [October 18, 2010, 3:13am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/2 "2010-10-18T03:13:17Z")
I could imagine that there’s a grain of truth to that. not that people actually “see ghosts” or “hallucinate” or anything, but that high-energy sound at frequencies that low could, uh, confuse a person’s equlibrium such that they’d experience anxiety and some degree of disorientation. I mean, there are things like Meniere’s syndrome or other inner-ear dysfunctions which can trigger anxiety, vertigo, and other unpleasantness. ---
**Author:** ![Electronic\_Chaos](https://avatars.discourse-cdn.com/v4/letter/e/bbe5ce/32.png) [@Electronic\_Chaos](https://boards.straightdope.com/u/Electronic_Chaos)\ **Post date:** [October 18, 2010, 3:22am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/3 "2010-10-18T03:22:02Z")
I can’t debunk the claim specifically, but about using your computer as a pitch detector: Most microphones only have a frequency response range above 20Hz. Unless you have a microphone specifically designed for picking up infrasonic sounds, it probably ain’t gonna work. ---
**Author:** ![kimera](https://avatars.discourse-cdn.com/v4/letter/k/f0a364/32.png) [@kimera](https://boards.straightdope.com/u/kimera)\ **Post date:** [October 18, 2010, 3:35am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/4 "2010-10-18T03:35:49Z")
Here is the skeptic dictionary entry. There is some evidence for it. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [October 18, 2010, 3:41am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/5 "2010-10-18T03:41:08Z")
> [@](#): > > Most microphones only have a frequency response range above 20Hz. that may be true for mics geared towards music recording, but measurement mics (like the B&K 4191/4192 or ACO Pacific 7012 that I use) are calibrated down to 3 Hz. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [October 18, 2010, 3:44am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/6 "2010-10-18T03:44:22Z")
> [@cptnred](#): > > This sounds amazing, but–at least at first glance–it also sounds like a load of crap. But at second glance…it is a _steaming load of crap._ > [@](#): > > 18 Hz is the resonant frequency of the human eye. What? Anytime you hear “frequency” and “resonance” together in a paragraph with no science to back it up, it’s very likely to be bafflespeak by a woo-meister. Along with “quantum” and “vibrations”, these terms are often used by people who have no idea what the terms mean. Do loud, high or low frequency sounds affect humans? Sure, but it’s a big jump to suggest they will see ghosts. More likely give them split eardrums or a headache, and when I get a headache, all I see is aspirin. ---
**Author:** ![Electronic\_Chaos](https://avatars.discourse-cdn.com/v4/letter/e/bbe5ce/32.png) [@Electronic\_Chaos](https://boards.straightdope.com/u/Electronic_Chaos)\ **Post date:** [October 18, 2010, 4:20am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/7 "2010-10-18T04:20:07Z")
> [@jz78817](#): > > that may be true for mics geared towards music recording, but measurement mics (like the B&K 4191/4192 or ACO Pacific 7012 that I use) are calibrated down to 3 Hz. I was specifically referring to the claim that you could use “any computer with a microphone or even an iPhone” to do it, though. To me, that implies that any off-the-shelf microphone will do. ---
**Author:** ![Simplicio](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@Simplicio](https://boards.straightdope.com/u/Simplicio)\ **Post date:** [October 18, 2010, 4:23am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/8 "2010-10-18T04:23:13Z")
> [@Musicat](#): > > But at second glance…it is a \*steaming load of crap.\*What? Anytime you hear “frequency” and “resonance” together in a paragraph with no science to back it up, it’s very likely to be bafflespeak by a woo-meister. Along with “quantum” and “vibrations”, these terms are often used by people who have no idea what the terms mean.. [NASA](http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA030476&Location=U2&doc=GetTRDoc.pdf) presumably knows what the terms mean and agree with the OP. ---
**Author:** ![dzero](https://avatars.discourse-cdn.com/v4/letter/d/5f9b8f/32.png) [@dzero](https://boards.straightdope.com/u/dzero)\ **Post date:** [October 18, 2010, 4:55am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/9 "2010-10-18T04:55:24Z")
I thought that was the [brown note.](http://en.wikipedia.org/wiki/Brown_note) ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [October 18, 2010, 12:17pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/10 "2010-10-18T12:17:57Z")
> [@Simplicio](#): > > > [@Musicat](#): > > > > But at second glance…it is a steaming load of crap.What? Anytime you hear “frequency” and “resonance” together in a paragraph with no science to back it up, it’s very likely to be bafflespeak by a woo-meister. Along with “quantum” and “vibrations”, these terms are often used by people who have no idea what the terms mean.. > > [NASA](http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA030476&Location=U2&doc=GetTRDoc.pdf) presumably knows what the terms mean and agree with the OP. That’s a shining example of taking a reference out of context and using it to prove something unrelated. Read the paper. It doesn’t suggest in the slightest that the resonant frequency of an eye leads to hallucinations or seeing ghosts; it is concerned with skull shaking in an aircraft or space vehicle affecting visual acuity. That report does not support the OP, but it may be where they got the idea. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [October 18, 2010, 1:11pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/11 "2010-10-18T13:11:04Z")
No, it’s an example of you claiming that he was making up terms, when the paper itself uses them. It doesn’t mean the OP is correct, but it does mean your castigation for using the wrong terminology is incorrect. ---
**Author:** ![Simplicio](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@Simplicio](https://boards.straightdope.com/u/Simplicio)\ **Post date:** [October 18, 2010, 1:32pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/12 "2010-10-18T13:32:35Z")
What **BigT** said. The point is that the wikipedia article isn’t just throwing around scientific terms at random like Deepak Chapra randomly inserts “quantum” into sentences to add the veneer of science, as you suggest. The resonant frequency of the eye is a real thing and it has a measurable physiological effect thats at least conceivably related to the phenomena being discussed. As to the larger theory that 18Hz noise cases haunted houses, I don’t think thats woo either. It might not br true, but its supported by at least some empirical evidence (the skepic’s dictionary mentions at least one published study, wikipedia a second). Indeed, its sort of the opposite of woo, in that its seeking a naturalistic explanation for supposed supernatural phenomena and then using experiments to back up the explanation. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [October 18, 2010, 1:47pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/13 "2010-10-18T13:47:05Z")
> [@Simplicio](#): > > What **BigT** said. The point is that the wikipedia article isn’t just throwing around scientific terms at random like Deepak Chapra randomly inserts “quantum” into sentences to add the veneer of science, as you suggest. The resonant frequency of the eye is a real thing and it has a measurable physiological effect thats at least conceivably related to the phenomena being discussed. > > As to the larger theory that 18Hz noise cases haunted houses, I don’t think thats woo either. It might not br true, but its supported by at least some empirical evidence (the skepic’s dictionary mentions at least one published study, wikipedia a second). > > Indeed, its sort of the opposite of woo, in that its seeking a naturalistic explanation for supposed supernatural phenomena and then using experiments to back up the explanation. From the Wikipedia article in the OP: > [@](#): > > Richard Wiseman said, "These results suggest that low frequency sound can cause people to have unusual experiences even though they cannot consciously detect infrasound. Some scientists have suggested that this level of sound may be present at some allegedly haunted sites and so cause people to have odd sensations that they attribute to a ghost—our findings support these ideas. With all due respect to Richard Wiseman, whom I admire very much, the tests do not support those ideas in the slightest. It’s a quantum leap from feeling bad when subjected to extreme low frequency sounds at extreme levels to imagining ghosts in old houses. Have any tests been done to show that old houses exhibit extremely low sounds at extremely high levels? And “tests” by “ghost-hunters,” which are notorious for using instruments to detect magnetic or acoustic phenomena, are unreliable and rarely repeatable. From the [reddit.com](http://reddit.com) article: > [@](#): > > I live near “haunted” Salem, MA and have found the 18 Hz signal in quite a few of them. More than once I have triggered a “ghost” in myself and others by standing in a spot with a strong 18 Hz signal for a couple of minutes. I challenge this person to replicate this and write it up in a paper; otherwise it is worthless. And note that nothing was said about high signal levels, which, according to the other tests, must be extreme before anything is noticed. If that claim is valid, why doesn’t a “funhouse” at a fair make a booth where you can see ghosts, every time? Apparently all you have to do is pump some loud, low sounds into a person and the ghosts appear. If not, then this claim is a load of hogwash. Someone is connecting dots that have no reason to be connected until proven. I feel bad when I take some medicine. Does that mean that the cause of ghosts is that medicine? Nonsense. Ssince this is GQ, the answer to the OP, “Does 18hz audio (“infrasound”) make people see ghosts?” is: There is insufficient evidence to support that conclusion at this time. ---
**Author:** ![Fridgemagnet](https://avatars.discourse-cdn.com/v4/letter/f/22d042/32.png) [@Fridgemagnet](https://boards.straightdope.com/u/Fridgemagnet)\ **Post date:** [October 18, 2010, 3:50pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/14 "2010-10-18T15:50:24Z")
Similar effects were investigated in the Haunt Project, an attempt to induce supernatural sightings by means of infrasound and electromagnetic fields ([abstract](http://www.ncbi.nlm.nih.gov/pubmed/18635163), Scientific American [article](http://www.scientificamerican.com/article.cfm?id=ghost-lusters-if-you-want)). The test subjects were interviewed and rated for spooky beliefs on the sheep/goat scale, and while most did feel a little odd subjected to these sonic and electromagnetic influences, only a few reported apparitions, and they tended to be those high up on the sheep scale. Bonus points for **dzero** for mentioning the Brown Note. 90s hardcoremonger Tad Doyle used to experiment on his audience at gigs in an attempt to reach this holy grail. I’m not sure if he had much success. Though the body can be influenced by infrasonic vibrations (the usual effect is nausea), it’s difficult to deliver the required energy by acoustic means. Eyeballs don’t have to be subjected to their natural resonant frequency to be vibrated, it’s just that they vibrate more efficiently at this sweet spot. From lots of experience of holding a percussive massager to my head, I can attest that this just produces blurred vision (at least in an old skeptic like me). The effect can be a bit weird though, as brighter objects (such as a TV screen in a moderately lit room) will appear more blurred than the darker surroundings. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [October 18, 2010, 5:53pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/15 "2010-10-18T17:53:50Z")
[Observations of Infrasound and Subsonic Disturbances Related to Severe Weather](http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.1971.tb03396.x/abstract) > [@](#): > > During the past 10 years the Geoacoustics Group of NOAA’s Wave Propagation Laboratory studied travelling low-frequency pressure variations related to thunderstorms and severe weather. Two general categories of waves were associated with severe weather conditions: ‘subsonic’ pressure disturbances and infrasonic waves with acoustic velocities. The low-frequency pressure variations were measured at the Earth’s surface using microphone arrays located at times thousands of kilometres from the severe-weather disturbance. The radiated infra- sound was related to thunderstorms penetrating the tropopause and spectral analyses were performed on several signals. Possible practical applications to storm warning and classification are discussed for both infrasound and ‘subsonic’ pressure disturbances. Past measurements of these signals are reviewed. [Infrasonic and Near Infrasonic Atmospheric Sounding and Imaging](http://www.esrl.noaa.gov/psd/programs/infrasound/infrasonic.html) [http://www.esrl.noaa.gov/psd/programs/infrasound/](http://www.esrl.noaa.gov/psd/programs/infrasound/) ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [October 18, 2010, 9:21pm UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/16 "2010-10-18T21:21:47Z")
Related Straight Dope column: [Why is bass so boomy, and what can I do about it? - The Straight Dope](http://www.straightdope.com/columns/read/2761/why-is-the-bottom-end-of-the-music-spectrum-so-boomy-and-annoying) Folks could also just read Tandy’s original technical papers and the Nasa papers (referenced by Nasa) and see for themselves what they think. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [October 19, 2010, 12:40am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/17 "2010-10-19T00:40:04Z")
> [@Fridgemagnet](#): > > Eyeballs don’t have to be subjected to their natural resonant frequency to be vibrated, it’s just that they vibrate more efficiently at this sweet spot. From lots of experience of holding a percussive massager to my head, I can attest that this just produces blurred vision (at least in an old skeptic like me). The effect can be a bit weird though, as brighter objects (such as a TV screen in a moderately lit room) will appear more blurred than the darker surroundings. I’ll share a related anecdote: Around 1988, when I was a grad student, we had a lab with a computer, a Sun IIRC, set up at one end of the lab, that could be seen from long ways away, maybe up to 100 feet. I found that if I was far away, and bit into a Dorito (a corn tortilla chip, for people outside the US), the screen would appear to flash. If I got closer, to maybe 30 feet, the effect would go away. At the time, and still, I attributed this to the sound vibrations of the crunch causing small ripples on the surface of my eyeball. The rest of the room didn’t flicker or flash, so I’d guess the CRT’s raster scanning was necessary for the effect. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [October 19, 2010, 1:25am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/18 "2010-10-19T01:25:04Z")
This is obvious proof that ghosts are attracted to things vibrating at 18 Hz. ---
**Author:** ![Magiver](https://avatars.discourse-cdn.com/v4/letter/m/4491bb/32.png) [@Magiver](https://boards.straightdope.com/u/Magiver)\ **Post date:** [October 19, 2010, 3:06am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/19 "2010-10-19T03:06:01Z")
> [@ZenBeam](#): > > I’ll share a related anecdote: > > Around 1988, when I was a grad student, we had a lab with a computer, a Sun IIRC, set up at one end of the lab, that could be seen from long ways away, maybe up to 100 feet. I found that if I was far away, and bit into a Dorito (a corn tortilla chip, for people outside the US), the screen would appear to flash. If I got closer, to maybe 30 feet, the effect would go away. At the time, and still, I attributed this to the sound vibrations of the crunch causing small ripples on the surface of my eyeball. The rest of the room didn’t flicker or flash, so I’d guess the CRT’s raster scanning was necessary for the effect. You can do the same thing with a juice harp. It took me a minute to realize it was my eyes and not the TV that was causing the effect. I don’t think it was hitting the resonant frequency of my eyes but it was causing my eyes to vibrate at the frequency of the TV which I suppose was 60 hz. My experience with objects hitting a resonant frequency is something best described as a feedback loop where the object increases vibration. I once had a bad wheel bearing in a car that would vibrate badly when the exhaust of my car or a passing car hit a certain frequency. The wheel assembly shook violently if I didn’t slow down or speed up. ---
**Author:** ![Gukumatz](https://avatars.discourse-cdn.com/v4/letter/g/74df32/32.png) [@Gukumatz](https://boards.straightdope.com/u/Gukumatz)\ **Post date:** [October 19, 2010, 4:30am UTC](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518/20 "2010-10-19T04:30:05Z")
I’m on the fence. On the one hand, it looks like a piece of sensationalist crap. They’ve got evidence to cover the allegation that “something happens when external force causes your eyes to vibrate at a certain Hz”, not “18 Hz makes your eyes see ghosts!” On the other hand, the brain is known to produce mild hallucinations when it’s under, for instance, total sensory deprivation. (The classic black room with white noise experiment, which I’ve tried for myself.) [Next page](https://boards.straightdope.com/t/does-18hz-audio-infrasound-make-people-see-ghosts/557518.md?page=2)