I came with another unusual question. Recently, during my little research in hearing and some of its phenomena, i found a term called RF hearing, which mean that people "hear" radio frequencies, electromagnetic fields and microwaves.

Do you hear something EXTRA ?


12 Answers 12



I'm sure you're not hearing RF from your LCD. Record it with a microphone and look on a spectrum analyzer, and you'll just see some tones in the kHz from the backlight electronics.


I doubt they're actually hearing radio frequencies, more likely they're hearing a high-pitched electrical noise from one of the components and mistaking it for the electrical field. No component is ideal, and there is always some energy lost to an extra process (heat, noise, etc.). I've always been able to tell when a TV is on in the next room (even if its muted), be it CRT or LCD. All electrical appliances make some sort of high-pitched noise when they have power running through them. It's just a question of which component, what the frequency output is, and whether or not you've protected your ears well enough to still be able to hear them.

There's also the myth of people being able to pick up and hear actual radio broadcast through replacement teeth, caps and fillings. I don't remember what their results were, but Mythbusters tackled that one. :)

Addtional Info: A lot of people here are mentioning that they can hear electronics when they're plugged in, powered on, etc. I think it's important to note that this is pretty common for anyone who has protected their ears over the years (including myself), and those frequencies that you're hearing are not above 20k. Are there frequency components above there? Yes...but you're just hearing the fundamentals, just the harmonics. Keep in mind that no electrical process runs in an ideal state. Almost all electronics give off heat, meaning that the electrical current is causing friction within the conductor. Friction equals a form of vibration, equals sound production. I'm beyond skeptical of this idea. Afterall, there are some forms of tinnitus that are not tied to hearing loss (meaning without damage to the inner ear). The human brain is a funky thing that can malfunction just like any other electrical device. If it can cause tinnitus without trauma to the ear, isn't it safe to assume that it can cause you to perceive other high frequency sounds by itself?

...Something to think about.


Flyback transformer of TV CRT: 15.7kHz

LCD Backlight inverter - also typically in kHz range.

p.s. Switching power supply of recent IT equipment - well audible too.


  • I can hear a CRT operating, even when it's in the next room for PAL that's 15625Hz.... Sucks when pitching ADR or foley/fx recording #CRT should be banned from sound studios!
    – user49
    Nov 2, 2010 at 9:40
  • The number of times I've heard VO with that tone in the background.. Jun 23, 2011 at 3:02
  • @Tim interesting! that would probably explain why I'm finding a dreaded tone up around 15k every so often on shared custom FX I have which were recorded some years ago (but never part of a sold library set where this would otherwise be EQd out). Never knew, learn something new every day! Dec 6, 2012 at 7:19

You will be amasingly surprised by this http://www.freedomfchs.com/auditoryresponsetopulsedrf.pdf

  • see the table when interviewed people claims that they hear buzzing from 1...MhZ Oct 30, 2010 at 18:03

The wikipedia article linked by endolith and the paper linked to by Pretaeperon both suggest that it's due to tissue in the head heating up (a millionth of a degree C) and expanding, sending an audible wave through your own head. So basically you hear your own head being microwave-cooked.

Both articles also suggest that in order to hear RF, you need to be exposed to a lot of transmitted power, to the point where it starts to be unhealthy (the wikipedia article refers to people standing within 100 meters from a Cold War radar antenna, and experiencing side effects such as dizziness and headache. I'm no biologist, but I can safely say that's not good for you). So yeah, at those hazardous situations you might hear something extra, but that's a very long way from typical everyday household or work environments where RF radiation is orders of magnitude weaker.


I did my USC grad thesis doc on the Microwave Auditory Effect (V2K:Voice To Skull), and interviewed two prominent scientists involved in the research, including the as of yet, only person to have been cited in "open" literature to have heard speech encoded and sent via microwaves.

The doc has a nice little description, animated graphics, and trippy side story.


The phenom happens in the 3gig range, occurs as clicks, whirs, and pops. For speech, microwave pulses have to be strung into tones, then tones strung into words. For sustained speech, youd be facing the aforementioned "cooking".

"Watson, come here...OH S#*T...His head just popped!!!"



Is that Johnson–Nyquist noise?

Usually you can hear capacitors charging and firing rapidly. That noise is real. A friend of mine was doing research with an electron microscope - thousands of capacitors firing at once when it's up to speed - and I though my teeth were going to explode. Most people walked into the room and heard silence.

  • Johnson-Nyquist noise is the hiss you hear when you turn up an amplifier all the way. The thing we're always trying to get as low as possible in recording equipment.
    – endolith
    Oct 31, 2010 at 4:19

There is also The Hum which some people hear - never been to the places mentioned so can't comment personally.


I've been hearing this for many years and the same frequency follows everywhere I go so it's not something in another room. If there is a lot of other noise, I don't hear it unless I concentrate on it. Recently, I started using a BodyMedia like the Body Bug from 24 hour fitness and I could hear that the first few days as I came out of deep sleep. It was definitely a lower pitch RF monitoring my brain waves inside my head. Their spec is 2400Hz. I'm guessing that my brain drew it into it's own frequency and now is vibrating at the same rate - much higher (5000Hz?) My brain is not being microwaved because it would have exploded by now!


Woah, great discussion and very interesting links in this post.

I don't think I have any supernatural hearing. I can hear CRTs like a knife in my brain and I can hear noise from my lcd monitors but not much else. I've found HF whine in mastered music and in a lot of behind the scenes studio footage. Real nasty.


I'm not sure what everyone else hears, but there's four types of noise I do hear that seems like few others can hear.

  1. flyback transformer noise. I don't hear this nearly as often as when everyone had CRT televisions, but I still own a CRT and I never turn it on because I can hear it, even when it's "off" It sits unplugged. It can be described as a very loud high pitch noise that can be confused for tinnitus. Going to another floor or room withthe doors shut is sufficient for muting it. I also hear...
  2. Electronic "charging" noise. In one example the power supply brick for my laptop makes this noise if the laptop is off, but the charger is plugged in. It's so irritating that I actually prefer the sound of the laptop being ON to hearing the charge noise. It is however not that loud. Similarly, it sounds like the noise when a camera flash is being charged, only between two high pitch points.
  3. Dog Whistles. I can't even describe what this sounds-feels like. Someone pointed one at me and it felt like my ears were rattling along with a buzzing feeling. It's more painful than actual sound.
  4. A loud tinnitus-like noise, only it's not a solid tone like tinnitus, rather it's a vaguely "noisy" tone that seems to bounce between two frequencies. I can hear it in certain locations if there's no overpowering noise.

I lived under powerlines until graduating high school. I don't think there is a connection as the power lines made a different kind of noise.


A few weeks ago I was alone in my room. It was totally quiet. However, I kept hearing a low (or should I say high) pitched whine. To me it sounded electrical. I thought it was coming from my laptop but it seemed distant. When I put my ear to it it didn't sound like it was coming from it. The air conditioner was on so I wrote it off as that's what it was since it seemed squeaky in the attic when it ran. I didn't remember hearing it again for a real long time. Now I'm hearing the same type of low pitched ring again. AC isn't on. Could it be RF or tinnitus??? It's not so bad that it causes me to not sleep or have certain side effects...but it does annoy me in a way that I know it's "there" and it won't stop. If someone's talking to me or if there's another noise that over powers it I usually don't notice it though. I'm only 27, should I be freaking out? I have been to lots of loud shows in my life time but I haven't been to a show in about a month.

Not the answer you're looking for? Browse other questions tagged or ask your own question.