Fun fact, with loud noises in the near ultrasound range, you can sometimes not hear them but they still cause pain, because the auditory stimulus and the pain stimulus are physically separated in the inner ear.
There's some kind of cricket where I live, can't hear the bastard but it feels like a pin stabbing my ear. Like it's _kind of_ a sound, but the sound is just pain
Largely because it’s just pressure waves Also the pain stimuli is seperate in EVERY organ system because we use specialised afferent nerve fibres to sense different kinds of pain - like we wouldnt have many C fibres because thermal isn’t as high an issue, but we’d have a lot of A alpha, beta and delta Delta is probs the important one because its the faster version of C fibres Alpha fibres are whats involved in the cochlear of the inner ear for balance and proprioception and the beta fibres are just touch
Interestingly, some UA-cam videos cause me to feel this unpleasant pressure in my ears, even if I can't hear any specific sound. I should dump the audio from the video the next time I come across one and check what frequencies I can see there.
Yeah as someone that gets completely bounced out of a yard like a cat when it has those little laser sensing get off my lawn devices lol.. this sounds like a hellscape! I can't wait for the cyberpunk dystopia where those are just basically everywhere and we've evolved around it with extra consequences!
6:40 a google search will show you many studies on the effects long term exposure to ultrasonic noise: "studies conducted to date in Poland and worldwide indicate that ultrasonic noise may cause excessive fatigue, headache, discomfort and irritation?
Can you point out where to find these? Probably LTT meant that what this particular device emits is untested, it's terrible wall of noise all the time.
Hi, the jammer actually works because of a phenomenon called intermodulation distortion, which is not an effect of the microphone’s non linear frequency response mentioned in 2:42, but rather of its non linear amplitude response. Basically the same difference between a tone control and a distortion pedal, just thought I’d clear that up.
If this one plays frequencies above nyquist, doesn't it just cause audible aliasing when the signal is converted to digital? Edit: actually this prob wouldnt happen because the mic wouldn't pick up those frequencies normally in the first place. IMD seems like the way to go.
At first I thought it was a simple square wave looking at the waterfall, but now I am pretty sure its probably chirped over a small frequency range with a sawtooth freq pwm right? I have never been great at looking at FTs and inverting it back to the time domain in my head.
@@scienceandmathHandle waterfall displays are nice for detection, for fine analysis, one really wants a spectrum analysis of amplitude, waveform and frequency.
@@Pbjtime yeah stuff like that would be filtered out properly by the microphone in the first place. What remains though, is the sidebands generated by whatever non-harmonic relationship you pick for your >20khz signals.
@@spvillano i'm pretty sure the fft-based noise removal subpatch i use in puredata would be able to clean it up quite a bit, i've accidentally left synths droning while booting it up and it cleaned them out well enough that i could hardly tell anything was different
Depending on the amount of decibels this thing outputs it is likely damaging your hearing. Just because you cannot hear something doesn't mean the acoustic pressure isn't harmful to your ears.
The writers and directors for this video are freaking awesome. Beautifully shot and the bits of comedy sprinkled through just elevate this video so much. Thank you for all you do
On older video game consoles like the Mega Drive (SEGA Genesis) had a low-pass filter integrated into the sound chip (more though the components and low quality of the signal forced higher frequencies to get lost), and this was fortunate as some retail games have bugs in them which cause extremely loud high-pitched chirping at all times. Without this filter, many games would have caused permanent hearing damage in many gamers. Nearly all emulators of these systems add a low-pass filter and enable it by default for this reason. Now we have a device that's portable and encouraged to be turned out for long periods of time which is also undetectable to the ordinary human ear that does the same thing. Fantastic.
One thing that's worth noting is that pressure waves (sound) outside of the range of human hearing can still cause hearing damage if it's loud enough. Many people who have spent significant amounts of time working with aircraft will be quite familiar with that.
@@raikhovalencia3835 Yes, but there surely is a frequency limit past which the cells stop being agitated because at some point the frequency becomes high enough that the cells don't have a chance to move much before the pressure switches from low to high every cycle. So there's a limit even to that. And by the way, some pets can hear much higher than humans can, so dogs could probably pick up that an insidious device like this is hidden somewhere.
@karolakkolo123 Not exactly true. There are pressure waves at ultra-low frequencies powerful enough to rupture your eardrums. Its not necessarily the frequency that determines its destructive properties, but the pressure and sound wave's energy. Any extremely loud noise can cause hearing damage, whether we hear if or not.
Epic walkthrough on understanding the limitations of such devices in real scenarios. Really got a clearer perspective on how these jammers could be defeated by different types of microphones and their placements.
About the potential danges of the Jammer. The way I see it, is that just because you cannot hear it, dosnt mean it can't hurt you. Hearing damage stems from the little hairs in your ears breaking of, due to excessive movement. What I could imagen is them being broken off over time, simply because they are still moving.
Totally.. same thing such as noises that may not sound loud but you are around them all the time causes hearing damage.. like noisy machinery .. why it's important to wear hearing projection even though it might not seem "loud"
i'm guessing something like this machine is what caused the hearing damage to the people in the cuban embassy. the US gov't hid this kind of audio jammer in the walls or whatever, didn't realize all the damage they were causing, and refused to own up once all the injuries were brought to light
except that if those hairs move, then you could hear. If you can't heara frequency, then that hair is either dead, or the nerve attatched to it is severed. The inverse is true, as well : if you can't hear, then no hairs are moving, or the nerve is severed to those frequencies. So the way I see it, unless you can hear something, you aren't getting hearing damage, especially if you're talking about high frequencies. Low frequencies however, could blow your eardrum, but at those energy levels, you'd be out of breath, burned and blown on your ass from the bomb that just blew up right next to you.
@@KlaevinThis is false. You can get hearing damage from ultrasound. The nerves have a response time, which means that high frequency signals won't get picked up properly. The hairs are still vibrating at that frequency, which can damage them if the sound is loud enough.
So, one other factor to consider is whether noise removal processes could remove it. It looked like the interference was cyclical af, so it's highly likely that an FFT-based solution could recognize those frequencies and remove them, while keeping the intensities at other frequencies the same. And if you were trying to surreptitiously record, you'd just need a brief moment (something like 2^16 audio samples would be plenty - aka about a second) of the machine going without anyone speaking to get what you need for that.
As a former Rochester, NYer the lip-reading factor still applies! Rochester among their vast history is a large deaf and hard of hearing community, like Washington DC and Los Angeles. You learn to lip read whether you realize it or not. Especially if someone's cochlear implant dies (or hell, if they don't have one) reading lips is needed to communicate. At least for me, this made me extremely aware (involuntarily) of the shape my mouth makes when saying words. Indeed though, Jeff did not veil his own eyes in darkness.
That’s the sound of your speakers compressing, if you had full spectrum coverage in your sound system, those parts of Zimmer’s work would sound like music instead of being totally crushed. This is also why you don’t want to send LFE to your mains. At times It’s just too much for them.
Oh you're not wrong! In so many ways! The theater when I finally saw dark Knight return whatever, the third one, was completely blowing out the speakers at the theater causing them to flop just like this stupid thing lol.. But hey sound mixing is hard apparently.
@@SwirlingDragonMist so I usually do that if I can, but I also have full range triples with 12-in woofers? Is is that going to be a problem as well? It just to me made sense to not use a subwoofer when I had four technical subwoofers that were capable?
In the same way that sound is pressure and an explosion can blast your ears out, sure, but for the most part, the ear is sensitive only to the frequencies that can damage it.
@@Shotblur Don't naysay safety related things you haven't googled. There are industries such as welding that make these ultrasonic noises, and we have studies indicating that these frequencies can cause hearing damage, as well as headaches and nausea.
The Sony transmitter Linus uses has a function to filter out ultrasound, it’s “OCUPNCY SENS = ON” in the menu. It’s designed to remove audio issues caused by ultrasonic occupancy sensors, I wonder if it has any effect on the jammer. It’s really a question of how linear the input stages before that filter are, because if the nonlinearities are high enough to act as a mixer, then the ultrasound will have already mixed down to audible frequencies and will be untouched by the filter.
@@benwu7980 he fuckes up a lot. started a few months ago. and he gets mad at his fuck ups and sometimes pushes it on his mates. also he wears a helmet a lot. idk if its a joke or a special needs thing.
@@benwu7980 i may spread some little evil misinformation but on top of my head i think he's just not an English speaker so it doesnt make sense even if he did answer the question
I remember a article about playing some high pitch noise in a mall to deter youth hanging out in the mall. They can hear it, but elders can not. And it was aimed to certain times of the day. I remembered this when the Eliah bit came in.
So true. They even started to develop crowd control versions for riot vans, but i dont know if its used or banned. (The microwave riot van one scares me the most)
@@craigpoole9218 Yeah , Mosquito anti-social anti-loitering. They installed one in a building I worked around 6 years ago, and had to have it disconnected within a week.
@@ComradePhoenix it's a french canadian slang and not sure my english isn't perfect maybe someone can correct me, but I think you can say "damn" or "holy shit" to replace Tabarnak. In France they would rather use Putain or Putain de merde
@@corrompu98 yeah that's the gist of it. Our swear words are pretty much all based on Christian church paraphernalia, so it doesn't translate well. We're essentially saying the name of the little cabinet they keep the host, the little white circles representing the body of Christ.
Topic being interesting is one thing, but this video was really well produced as well! From cutting off the background music for punchlines, to well written dialogue/script. 11/10.
This is the same jamming technique cheap RF jammers use. It’s not about frequency nonlinearity, but gain nonlinearity. An input tone that is too high will push the amplifier gain into the compressed region (instead of the linear region), leading all normal signals to be attenuated
Try this in a home with dogs and watch the reaction. You will find out really quickly that it's not for home use. And with more and more people having "service dogs" in the workplace, this wont be suited for there either. As to how it works, I suspect its not a beat frequency that you are hearing in the recording, but rather it's the sound of distortion in the mic element. It was a very smart move thinking of the large diaphragm mic. I hadn't expected that. But I did expect limited effect with the lav simply due to proximity. If the mic is close enough to your mouth and the jamming device far enough away, if still might be possible to cancel out or filter out the sound of the jammer. It HAS to distort the diaphragm all the way in order to block your audio. If it only moves the diaphragm half way, its likely that audio can be recovered.
@@DMSparky Better than the ROC is thinking. People always neglect the power that control of the St-Lawrence river represent. Quebec could really hurt the economy of Ontario if it blocked or heavily taxed passage of merchandise. And also there is a ginormous hydro electricity potential that Quebec cannot exploit because of how the federal control what can be built in the river.
What the heck is up with the production quality of this video?? The b roll, the jump cuts to natural reactions and natural feeling comedic reactions and responses?? New editor, you’re appreciated 😂
I remember seeing in several sci-fi TV shows, speakers were placed in the room and the characters put on masks to distort their voices, to prevent them from being picked up by bugs. With devices like this, science fiction is becoming science fact!
12:25 A PA speaker mounted in the ceiling tiles of the conference room can be used as a microphone. The 1970's vintage home intercom systems used 3 inch speakers that also acted as the microphone.
This video was so well-produced. The writing was great (I really like the "presentation" style of Linus in front of the Build Corner TV), and I LOVED the B-Roll shots of the mics. Honourable mention to the Lumafield CT scans too. Just an all-around quality video.
10:58 what you are seeing is called the inverse square law. Energy expands outward from the emission source like a growing bubble shape so the same energy is spread across a roughly hemisphere shaped surface area, so as the attenuation is a product of the distance squared.
For those that don't know, he didn't actually do it. He was just talking about it on WAN show and mistakenly thought "Hard R" refered to calling someone "Ret***ed". Luke informed him that it meant putting the r at the end of the n word.
Elijah hearing it is like how some people (like myself) can hear those ultrasonic sensors for animals. That, and love the Commander Riker sticker on the laptop!!
Those things are hell. While others then just go confused "I dont hear anything", it hurts my ears. I don't get why anyone can put those in their garden, often not even aligning them properly so everything sets them off. Or the so called mosquitoes, that generate high pitch noises only younger people can generally hear, to prevent a spot becoming a 'hanging out' spot. I walk past one quite often and in the evening it makes a high pitched noise, that my ears neither really like.
Or the sound of old CRT monitors and TVs, back in the day many people thought I was crazy when I said I knew whenever our neighbours were watching TV because I heard the sound of the picture tube through the walls 😂
Here's the thing, there's more to it than just overwhelming the diaphragm. You can blow out the mems diaphragm and have it just clipping out like mad, but you also have the digital aliasing of the audio it's recording that reduces the recorded frequency into the audible range, and you also get harmonics that are closer to audible noise as well. All of that makes ultrasound really hard to keep out of an audio recording. Generally speaking, mems mics are out for anything where high amplitude ultrasound is playing, as you found yourself.
In Scotland we actually have quite a few of these deployed in public (perhaps on a slightly different frequency) but turned down so they are just really irritating. As you said at the start of the episode, hearing becomes worse the older you get, so those under the age of 21 have a much higher range of hearing than older folk. These devices are used in places where it is inappropriate for teenagers to hang around (and often do like most teenagers, in groups, and at night) and are causing issues. There is some debate about them being used by companies (i.e. takeaways) because as you said long-term effects are not really studied yet, but their use here is for exactly the purpose that Elijah experienced (albeit at a much lower level) - namely to drive the teens loopy with the sound so they leave the immediate area.
Problem with them is that angry old folk put a handful of them in their front garden so they activate every time you walk past and when they live 3 doors down from the corner shop having a barrage of piercingly high pitched noise i think they are more of a nuisance then the kids around the area
Fun fact: Similar effects to this can occur naturally. Often when the ground shifts, or an old structure settles a bit. If it happens to occurred at the same frequency that the human eye resonates at (~15 hrtz) you'll experience visual hallucinations that are very consistent with people's reports of ghosts. Double fun fact, the human brain HATES when your eyes vibrate and you'll feel a sense of dread and panic set in too! And that's why the supernatural is just some weird low frequency sounds that can just kinda happen sometimes.
I feel Elijah, I myself can hear a lot of frequencies most people can't, so I suffer around cheap tech or soon-to-fail stuff. That thing must be hell to listen to
@@Scarlet_Soul I seen my mom's set-ups and said "What's wrong with your charger" And she's like, what it's fine. Mom, it sounds like it's going to explode.
I'm glad they did a smattering of different mic, but it would have been interesting to see how the polar patterns of a given microphone may have correlated, rather than just the external geometries for directionality.
For those who suggest a use for this thing: some people do hear them and can hear them a lot. Putting something like this in a public space would risk health of many people, this could be illegal. Otherwise the science behind this thing is pretty cool.
It may damage a person's hearing even if they can't hear the sound. There's only a little scientific evidence of this, but if it's the case, the person wouldn't even know to protect themselves.
Doing so would drive off the handful of customers that can actually hear it and once it's use got out in the open (which wouldn't take long since some people can hear it) could lead to lawsuits from people claiming hearing damage or other BS problems which may very well be frivolous but still cost money to defend. And of course once that news is out, using it would be pointless since anyone wanting to make a video in your store could easily find out how to defeat it.
@@wingracer1614 Im not sure what it is these some people are hearing, is it that they have above average sound range? Why did elijah nearly explode at that sound?
From the waveform, it does seem to cover the real signal well. But that’s not very important. Did you guys try to do a Fourier Transform to see if you can filter out the jamming and reconstruct the actual speech?
I really like these deep dives on interesting tech. Even if it's not something I would ever use, just having the understanding of how it works, how the microphones are designed and how these kinds of things interact with those designs is interesting
exposure to mobile jammer radiofrequency radiation for as little as one hour can negatively impact human hearing, especially at frequencies of 1000 and 2000 Hz. Other studies have also suggested that jammer usage may have adverse health effects on humans, including: Brain tumors: Excessive use may increase the risk of brain tumors Cognitive performance: Jammers may interfere with cognitive performance Other adverse effects: Other adverse effects include headaches, fatigue, and skin irritation
Actually it's pretty amazing how well this thing seems to work. You expect kind of nothing from Aliexpress but this would work in many situations. Even just as an 'additional layer of protection' for secret meetings. It's not failproof sure, but this combined with already existing measurements would be an incridible extra to have. They seem to have put a lot of work and thought into it, impressive.
About the Quebec joke .... LTT is one of my main ROC content .. just acknowledging Quebec existence is nice to ear... even in this circumstances. Et oui on va peut être décalisser, vous laisser tout seul avec Toronto!
This is useful for in-person conversations only. Phone conversations will obviously not be affected, unless you want the person on the other end to not hear what you're saying.
I don't really ever comment, but I really liked this video, especially the balance between technical stuff and the real world implications. Great job and please do more of the deep dive tech stuff in the future. Love it.
Linus, the spectrograms were interpreted incorrectly. The spectrograms you showed were more than likely aliasing, or wrapping, in the frequency domain. A big tell is the repeating zigzag patterns. You'd need a wider bandwidth in your spectrum to capture the actual signal, assuming that it is a continuous waveform. Try doing a fft on a longer record length to produce a single spectrum. My gut feeling is that there is in fact, a strong low frequency signal, in addition to different harmonics that resonate with mic membranes.
you should look at the speech jammer made by Benn Jordan its very interesting and its similair to how this works in the way that we cant hear it but microphones can as it covers the whole spectrum
Poor Elijah has to now wear both helmet and ear plugs.
i feel that. i can hear stupid high frequencies.
Why would it be illegal?
Nah, they sold the helmet.
@@junkheadINChealth effects might be really bad. Just because you can’t hear it doesn’t mean it can’t hurt your ears
So you are saying we need to pull a ThunderScreech out of mothballs for Elijah
Fun fact, with loud noises in the near ultrasound range, you can sometimes not hear them but they still cause pain, because the auditory stimulus and the pain stimulus are physically separated in the inner ear.
Isnt that what they used to try to implement as crowd/riot control for the police?
There's some kind of cricket where I live, can't hear the bastard but it feels like a pin stabbing my ear. Like it's _kind of_ a sound, but the sound is just pain
Largely because it’s just pressure waves
Also the pain stimuli is seperate in EVERY organ system because we use specialised afferent nerve fibres to sense different kinds of pain - like we wouldnt have many C fibres because thermal isn’t as high an issue, but we’d have a lot of A alpha, beta and delta
Delta is probs the important one because its the faster version of C fibres
Alpha fibres are whats involved in the cochlear of the inner ear for balance and proprioception and the beta fibres are just touch
Interestingly, some UA-cam videos cause me to feel this unpleasant pressure in my ears, even if I can't hear any specific sound. I should dump the audio from the video the next time I come across one and check what frequencies I can see there.
Yeah as someone that gets completely bounced out of a yard like a cat when it has those little laser sensing get off my lawn devices lol.. this sounds like a hellscape! I can't wait for the cyberpunk dystopia where those are just basically everywhere and we've evolved around it with extra consequences!
Not “Jeffrey Epstein didn’t kill himself” lol lip reading was a little easy for that one
You beat me to it!
right! XD lip reading skills too good tp know he saying
Where does he say that? At the beginning?
@@Felinusfish0:43
BRUH
6:40 a google search will show you many studies on the effects long term exposure to ultrasonic noise:
"studies conducted to date in Poland and worldwide indicate that ultrasonic noise may cause excessive fatigue, headache, discomfort and irritation?
And i am sure it's can damage ears .it's still blasting huge noise .
Can you point out where to find these? Probably LTT meant that what this particular device emits is untested, it's terrible wall of noise all the time.
Can confirm worked in a lab where we were always using the ultrasonic, I went mad got fired for being an asshole.
Certain frequencies are capable of making you throw up and unable to move. There's a crowd control device that does exactly this.
they need to double check, as a Pole I can say that all aforementioned symptoms are simply related to living in Poland :P
Hi, the jammer actually works because of a phenomenon called intermodulation distortion, which is not an effect of the microphone’s non linear frequency response mentioned in 2:42, but rather of its non linear amplitude response. Basically the same difference between a tone control and a distortion pedal, just thought I’d clear that up.
If this one plays frequencies above nyquist, doesn't it just cause audible aliasing when the signal is converted to digital?
Edit: actually this prob wouldnt happen because the mic wouldn't pick up those frequencies normally in the first place. IMD seems like the way to go.
At first I thought it was a simple square wave looking at the waterfall, but now I am pretty sure its probably chirped over a small frequency range with a sawtooth freq pwm right? I have never been great at looking at FTs and inverting it back to the time domain in my head.
@@scienceandmathHandle waterfall displays are nice for detection, for fine analysis, one really wants a spectrum analysis of amplitude, waveform and frequency.
@@Pbjtime yeah stuff like that would be filtered out properly by the microphone in the first place. What remains though, is the sidebands generated by whatever non-harmonic relationship you pick for your >20khz signals.
@@spvillano i'm pretty sure the fft-based noise removal subpatch i use in puredata would be able to clean it up quite a bit, i've accidentally left synths droning while booting it up and it cleaned them out well enough that i could hardly tell anything was different
5:19 "I don't even like water cooling! I think it's a waste of the money!"
Ok Linus
Damn nice catch.
Good one !
It's a waste of my money*
You lip readers scare me far worse than any recording device 😂
He doesn't though. It just gets views!
0:43 Linus is a real one for that.
he truly didn't kill himself
😭😭😭😭😭
Idk about truly but seems you got part if that right 😂😂😂@lurac5710
Did he just say-
no way my mans Linus Tech Tips-
Did he say Jeffry Epstein didn't kill himself?
6th sense finally came out to do the job
Depending on the amount of decibels this thing outputs it is likely damaging your hearing. Just because you cannot hear something doesn't mean the acoustic pressure isn't harmful to your ears.
Yep. Cause its still vibrating, just the vibration cannot be understood anymore
i mean you can either be cancelled or be deaf, we all know what option we are choosing
I expect a bunch of corrupt cops trying to prevent being recorded being crap cops in america to go deaf then.
If you can be cancelled and blind you can probably be cancelled and deaf as well.@@12thMandalorian
6:41 covers this point
The writers and directors for this video are freaking awesome. Beautifully shot and the bits of comedy sprinkled through just elevate this video so much. Thank you for all you do
On older video game consoles like the Mega Drive (SEGA Genesis) had a low-pass filter integrated into the sound chip (more though the components and low quality of the signal forced higher frequencies to get lost), and this was fortunate as some retail games have bugs in them which cause extremely loud high-pitched chirping at all times. Without this filter, many games would have caused permanent hearing damage in many gamers. Nearly all emulators of these systems add a low-pass filter and enable it by default for this reason.
Now we have a device that's portable and encouraged to be turned out for long periods of time which is also undetectable to the ordinary human ear that does the same thing. Fantastic.
8:12 that's colins actual voice
Biblically accurate voice of Colin
Is he saying the obvious "yeah, what the fuck?"
His voice is higher pitched than I expected?
@specodhec341 , could be a homophone.
I don't want to be reminded about this game existing 50 times in a day
One thing that's worth noting is that pressure waves (sound) outside of the range of human hearing can still cause hearing damage if it's loud enough. Many people who have spent significant amounts of time working with aircraft will be quite familiar with that.
In what way does it damage the hearing if it cannot be picked up?
@@fungo6631 The eardrum is still agitated, the sensory cells in the cochlea still get shaken around and break.
@@woolver42so theoretically this device could be used as a super evil hidden hearing damage inducer???
@@raikhovalencia3835 Yes, but there surely is a frequency limit past which the cells stop being agitated because at some point the frequency becomes high enough that the cells don't have a chance to move much before the pressure switches from low to high every cycle. So there's a limit even to that. And by the way, some pets can hear much higher than humans can, so dogs could probably pick up that an insidious device like this is hidden somewhere.
@karolakkolo123 Not exactly true. There are pressure waves at ultra-low frequencies powerful enough to rupture your eardrums. Its not necessarily the frequency that determines its destructive properties, but the pressure and sound wave's energy. Any extremely loud noise can cause hearing damage, whether we hear if or not.
So it's a Hypno-toad.
LTT Labs is a tabloid compared to Gamers Ne--ALL GLORY TO THE HYPNOTOAD
Or sequel to Tenet? I prefer Hypnotoad episodes.
ALL GLORY TO THE HYPNOTOAD
that's hilarious hahahahahaa
ALL GLORY TO THE HYPNOTOAD
Epic walkthrough on understanding the limitations of such devices in real scenarios. Really got a clearer perspective on how these jammers could be defeated by different types of microphones and their placements.
DON'T get this if you own a dog.
But DO get it if your neighbor does. I’ve been looking for a doggie STFU button for a while.
@@msmith3395 Chaotic evil energy lol
Instruction unclear. Sold my dog.
@@Flornmonk that's chaotic neutral tho
@@Luis-gz3oo buying that jammer just to shut up your neighbor's dog is pretty much the definition of evil haha
Elijah is not the the meme that LTT needed, but is 100% the meme it got.
About the potential danges of the Jammer.
The way I see it, is that just because you cannot hear it, dosnt mean it can't hurt you.
Hearing damage stems from the little hairs in your ears breaking of, due to excessive movement. What I could imagen is them being broken off over time, simply because they are still moving.
Totally.. same thing such as noises that may not sound loud but you are around them all the time causes hearing damage.. like noisy machinery .. why it's important to wear hearing projection even though it might not seem "loud"
i'm guessing something like this machine is what caused the hearing damage to the people in the cuban embassy. the US gov't hid this kind of audio jammer in the walls or whatever, didn't realize all the damage they were causing, and refused to own up once all the injuries were brought to light
except that if those hairs move, then you could hear. If you can't heara frequency, then that hair is either dead, or the nerve attatched to it is severed. The inverse is true, as well : if you can't hear, then no hairs are moving, or the nerve is severed to those frequencies.
So the way I see it, unless you can hear something, you aren't getting hearing damage, especially if you're talking about high frequencies.
Low frequencies however, could blow your eardrum, but at those energy levels, you'd be out of breath, burned and blown on your ass from the bomb that just blew up right next to you.
@@KlaevinThis is false. You can get hearing damage from ultrasound. The nerves have a response time, which means that high frequency signals won't get picked up properly. The hairs are still vibrating at that frequency, which can damage them if the sound is loud enough.
Hearing loss tends to start with higher frequencies first.
This jammer sound effect sounds like the sandworm from dune 2
lol it replaces any recorded audio with a hanz zimmer soundtrack
The Reapers are invading.
Linus Al Gaib!!!
More like the HYPNOTOAD.
FRRR I thought it was just edited from the video to make it seem that way, but that makes so much sense in terms of the movie
So, one other factor to consider is whether noise removal processes could remove it. It looked like the interference was cyclical af, so it's highly likely that an FFT-based solution could recognize those frequencies and remove them, while keeping the intensities at other frequencies the same. And if you were trying to surreptitiously record, you'd just need a brief moment (something like 2^16 audio samples would be plenty - aka about a second) of the machine going without anyone speaking to get what you need for that.
As a former Rochester, NYer the lip-reading factor still applies! Rochester among their vast history is a large deaf and hard of hearing community, like Washington DC and Los Angeles. You learn to lip read whether you realize it or not. Especially if someone's cochlear implant dies (or hell, if they don't have one) reading lips is needed to communicate. At least for me, this made me extremely aware (involuntarily) of the shape my mouth makes when saying words. Indeed though, Jeff did not veil his own eyes in darkness.
Finally, a Hans Zimmer machine
That's so close to the sound haha
Interstellar intensify
That’s the sound of your speakers compressing, if you had full spectrum coverage in your sound system, those parts of Zimmer’s work would sound like music instead of being totally crushed. This is also why you don’t want to send LFE to your mains. At times It’s just too much for them.
Oh you're not wrong! In so many ways! The theater when I finally saw dark Knight return whatever, the third one, was completely blowing out the speakers at the theater causing them to flop just like this stupid thing lol.. But hey sound mixing is hard apparently.
@@SwirlingDragonMist so I usually do that if I can, but I also have full range triples with 12-in woofers? Is is that going to be a problem as well? It just to me made sense to not use a subwoofer when I had four technical subwoofers that were capable?
2:36 sick use of the lumafield
Didn't even think about that when watching it! That's so cool, thanks for pointing that out!
Worth noting that high amplitude noises, regardless of whether we can hear them, can still damage our hearing.
In the same way that sound is pressure and an explosion can blast your ears out, sure, but for the most part, the ear is sensitive only to the frequencies that can damage it.
@@ShotblurEnergy is energy
@@rkan2Not if it isn’t absorbed somewhere it shouldn’t be.
@@Shotblur Don't naysay safety related things you haven't googled. There are industries such as welding that make these ultrasonic noises, and we have studies indicating that these frequencies can cause hearing damage, as well as headaches and nausea.
Love the use of video feedback loops for the shots at 3:17 and 8:39. Looks super sleek with the blue, red and purple lighting! 🔥
The Sony transmitter Linus uses has a function to filter out ultrasound, it’s “OCUPNCY SENS = ON” in the menu. It’s designed to remove audio issues caused by ultrasonic occupancy sensors, I wonder if it has any effect on the jammer. It’s really a question of how linear the input stages before that filter are, because if the nonlinearities are high enough to act as a mixer, then the ultrasound will have already mixed down to audible frequencies and will be untouched by the filter.
No, because the jammer causes a cascade disruption of the microphone diaphragm at audible frequencies. This is a physical effect, not a digital one.
I loved that little joke about Colin's only opportunity to finally let his voice be heard, was jammed lol
I like to think of myself as pretty clued in on most internet memes or trivia, but I have no idea where the Colin one started from.
@@benwu7980 Same. Let me wait here for someone to enlighten us.
@@benwu7980 he fuckes up a lot. started a few months ago. and he gets mad at his fuck ups and sometimes pushes it on his mates. also he wears a helmet a lot. idk if its a joke or a special needs thing.
@@pacboygamer6728 thats not colin that's elijah
@@benwu7980 i may spread some little evil misinformation but on top of my head i think he's just not an English speaker so it doesnt make sense even if he did answer the question
I remember a article about playing some high pitch noise in a mall to deter youth hanging out in the mall. They can hear it, but elders can not. And it was aimed to certain times of the day. I remembered this when the Eliah bit came in.
They've been banned I believe, in some countries. As they can damage the Ear with prolonged exposure.
So true. They even started to develop crowd control versions for riot vans, but i dont know if its used or banned. (The microwave riot van one scares me the most)
Mosquito alarm
They still do this where I live. I'm 31 and still annoyed
@@craigpoole9218 Yeah , Mosquito anti-social anti-loitering. They installed one in a building I worked around 6 years ago, and had to have it disconnected within a week.
0:43 the fact that we can absolutely tell what he said is hilarious holy shit
What did he say tho? I'm guessing he said 'Jeffery Dahmer didn't kill himself !' but I'm not too sure
@@the_legendary_poseidonWrong Jeffrey, its Epstein not Dahmer
Lmao what what he said was fact.
on 05:18 he says "i gotta tell you. i don't even like watercooling and it's a waste of flipping money"
5:29 I knew it wasn't the end of the video because Linus didn't let me hear more from their sponsor
rip the hearing aid users
OMG I'm dying the Quebec joke with the editors note even throwing down a "Tabarnak" was icing on the cake thanks for keeping it Canadian!
They really dared. Tabarnak osti caliss 😠😆
never heard a single canadian say tabarnak.
As an American, I have no idea what the hell a Tabarnak is, but I strongly suspect the Quebec joke was done to fill in a canadian content quota.
@@ComradePhoenix it's a french canadian slang and not sure my english isn't perfect maybe someone can correct me, but I think you can say "damn" or "holy shit" to replace Tabarnak.
In France they would rather use Putain or Putain de merde
@@corrompu98 yeah that's the gist of it. Our swear words are pretty much all based on Christian church paraphernalia, so it doesn't translate well. We're essentially saying the name of the little cabinet they keep the host, the little white circles representing the body of Christ.
Topic being interesting is one thing, but this video was really well produced as well! From cutting off the background music for punchlines, to well written dialogue/script.
11/10.
Most definitely. One of their best yet.
The headphone guy joke at 2:00 was hilarious.
I found it to be high end clickbait, as it danced around serious engineering or legal analysis relevant to topics presented as misleading fluff.
3:45 Bro it knits a blanket out of sound waves. That's awesome!
This is the same jamming technique cheap RF jammers use. It’s not about frequency nonlinearity, but gain nonlinearity. An input tone that is too high will push the amplifier gain into the compressed region (instead of the linear region), leading all normal signals to be attenuated
Try this in a home with dogs and watch the reaction. You will find out really quickly that it's not for home use. And with more and more people having "service dogs" in the workplace, this wont be suited for there either. As to how it works, I suspect its not a beat frequency that you are hearing in the recording, but rather it's the sound of distortion in the mic element. It was a very smart move thinking of the large diaphragm mic. I hadn't expected that. But I did expect limited effect with the lav simply due to proximity. If the mic is close enough to your mouth and the jamming device far enough away, if still might be possible to cancel out or filter out the sound of the jammer. It HAS to distort the diaphragm all the way in order to block your audio. If it only moves the diaphragm half way, its likely that audio can be recovered.
I love the Riker stickers on the laptop in the "meeting room". Classic Riker stepping over chairs to sit in them.
Power moves like that are why he's number one.
Back injuries exacerbated by the early costumes being too tight made one of the best power moves, from being thrown from a horse
Oh thank goodness, I was going to ask why it was Riker sitting on a Christmas tree 😅
12:48
As a French Canadian, I approve this message.
I believe in a 'distinct society', as long as someone else pays for it.
Maybe someday
As a US-CAN dual citizen, I also approve this message.
Do it. I’d love to see how a provincial Brexit would go. Quexit I guess.
@@DMSparky Better than the ROC is thinking. People always neglect the power that control of the St-Lawrence river represent. Quebec could really hurt the economy of Ontario if it blocked or heavily taxed passage of merchandise. And also there is a ginormous hydro electricity potential that Quebec cannot exploit because of how the federal control what can be built in the river.
What the heck is up with the production quality of this video?? The b roll, the jump cuts to natural reactions and natural feeling comedic reactions and responses?? New editor, you’re appreciated 😂
It’s Mark
@@Matthew-ht5yn Oh, hi, mark.
I remember seeing in several sci-fi TV shows, speakers were placed in the room and the characters put on masks to distort their voices, to prevent them from being picked up by bugs. With devices like this, science fiction is becoming science fact!
12:25 A PA speaker mounted in the ceiling tiles of the conference room can be used as a microphone. The 1970's vintage home intercom systems used 3 inch speakers that also acted as the microphone.
That is what is known as a dynamic microphone. Yes, an 8 ohm speaker can also be used as a microphone.
2:48 I like how he didn't need to change from his regular voice for the high pitch
I love the Riker Maneuver stickers on the lid of the laptop.
Here for when Linus sounds like an A-10 Warthog
Someone needs to photoshop this RIGHT NOW
This video was so well-produced. The writing was great (I really like the "presentation" style of Linus in front of the Build Corner TV), and I LOVED the B-Roll shots of the mics. Honourable mention to the Lumafield CT scans too. Just an all-around quality video.
10:58 what you are seeing is called the inverse square law. Energy expands outward from the emission source like a growing bubble shape so the same energy is spread across a roughly hemisphere shaped surface area, so as the attenuation is a product of the distance squared.
Loved the spectrogram and the explanations. Well done for taking a complicated system (frequency jamming) and translating it into plain English!
Yeah, me too! Tho, might use Praat software next time instead ;)
I can't believe how many times he said the 'N' word just to prove a point
Linus must've been sick to claim that thing about Norwegians.
he really dropped that hard R
Linus and Grant O'Brien, both in one week. What a shame....
With a hard r.
Contact your local lip reader for a transcript of the scrambled audio. 😅😂
Linus could have used this when he dropped that HARD R!!!!
💀
For those that don't know, he didn't actually do it. He was just talking about it on WAN show and mistakenly thought "Hard R" refered to calling someone "Ret***ed". Luke informed him that it meant putting the r at the end of the n word.
@@ZachMauch Don't listen to this guy. Just misinformation. Linux Sebastian actually said the ultra super duper hard R
@@theRPGmaster CAN CONFIRM
@@DarkForce2024So you're saying that Stellar Blade devs should have also had this thing in their building.
Linus really reviewed this product so he could revisit the topic of the “hard R” without any backlash
This video reminded me that my very common house plant, Cactuar, is due for its yearly watering. Thanks LTT 🙂
Oh soo that's how Futurama's Hypnotoad works.
Elijah hearing it is like how some people (like myself) can hear those ultrasonic sensors for animals.
That, and love the Commander Riker sticker on the laptop!!
I can hear those frequencies too and they can really mess you up and make you feel like you want to throw up
@@HelamanGile have you tried barking at them? I have an acquaintance who thinks that works
Those things are hell. While others then just go confused "I dont hear anything", it hurts my ears. I don't get why anyone can put those in their garden, often not even aligning them properly so everything sets them off.
Or the so called mosquitoes, that generate high pitch noises only younger people can generally hear, to prevent a spot becoming a 'hanging out' spot. I walk past one quite often and in the evening it makes a high pitched noise, that my ears neither really like.
Or the sound of old CRT monitors and TVs, back in the day many people thought I was crazy when I said I knew whenever our neighbours were watching TV because I heard the sound of the picture tube through the walls 😂
@@Warutteri I'm well into my 40's and I can still hear coil whine from some devices that even my teenaged kids can't hear. It's pretty annoying.
Here's the thing, there's more to it than just overwhelming the diaphragm. You can blow out the mems diaphragm and have it just clipping out like mad, but you also have the digital aliasing of the audio it's recording that reduces the recorded frequency into the audible range, and you also get harmonics that are closer to audible noise as well. All of that makes ultrasound really hard to keep out of an audio recording. Generally speaking, mems mics are out for anything where high amplitude ultrasound is playing, as you found yourself.
In Scotland we actually have quite a few of these deployed in public (perhaps on a slightly different frequency) but turned down so they are just really irritating. As you said at the start of the episode, hearing becomes worse the older you get, so those under the age of 21 have a much higher range of hearing than older folk. These devices are used in places where it is inappropriate for teenagers to hang around (and often do like most teenagers, in groups, and at night) and are causing issues. There is some debate about them being used by companies (i.e. takeaways) because as you said long-term effects are not really studied yet, but their use here is for exactly the purpose that Elijah experienced (albeit at a much lower level) - namely to drive the teens loopy with the sound so they leave the immediate area.
Problem with them is that angry old folk put a handful of them in their front garden so they activate every time you walk past and when they live 3 doors down from the corner shop having a barrage of piercingly high pitched noise i think they are more of a nuisance then the kids around the area
Fun fact: Similar effects to this can occur naturally. Often when the ground shifts, or an old structure settles a bit. If it happens to occurred at the same frequency that the human eye resonates at (~15 hrtz) you'll experience visual hallucinations that are very consistent with people's reports of ghosts. Double fun fact, the human brain HATES when your eyes vibrate and you'll feel a sense of dread and panic set in too! And that's why the supernatural is just some weird low frequency sounds that can just kinda happen sometimes.
I feel Elijah, I myself can hear a lot of frequencies most people can't, so I suffer around cheap tech or soon-to-fail stuff. That thing must be hell to listen to
Chargers go eeeeeee
@@Scarlet_SoulOh yeah the cheap Chinese ones absolutely do
@@Scarlet_Soul I seen my mom's set-ups and said "What's wrong with your charger"
And she's like, what it's fine.
Mom, it sounds like it's going to explode.
Wow you're so unique and cool
The one at 5:20 is him saying something along the lines of "I kid you, I don't even like watercooling. And, it's a waste of money"
The new lumafield scans are so nice in these videos!
Thanks guys, your tests and inferences are great, thanks!
I'm glad they did a smattering of different mic, but it would have been interesting to see how the polar patterns of a given microphone may have correlated, rather than just the external geometries for directionality.
Using the a frequency response that matches the handheld you’re holding while talking about it…. So good. Thank you!
7:44 "whiny tube TV"; yeah, I had that when I was a kid. I could tell there was a TV on from the next room.
For those who suggest a use for this thing: some people do hear them and can hear them a lot. Putting something like this in a public space would risk health of many people, this could be illegal.
Otherwise the science behind this thing is pretty cool.
It may damage a person's hearing even if they can't hear the sound. There's only a little scientific evidence of this, but if it's the case, the person wouldn't even know to protect themselves.
I love the Cactuar in the meeting room!!!
This was a great video. Informative and funnier than normal. Thanks!
This was a really great video guys, great production, super cool effects/visuals/ideas/jokes and all the beats where they should be! Love it!
stores should use this to prevent "prank" youtubers from making content
Doing so would drive off the handful of customers that can actually hear it and once it's use got out in the open (which wouldn't take long since some people can hear it) could lead to lawsuits from people claiming hearing damage or other BS problems which may very well be frivolous but still cost money to defend. And of course once that news is out, using it would be pointless since anyone wanting to make a video in your store could easily find out how to defeat it.
@@wingracer1614 stores used to have a "mosquito" that makes a high pitch sound that specifically aim at teens loitering
People are evil
@@wingracer1614 Im not sure what it is these some people are hearing, is it that they have above average sound range? Why did elijah nearly explode at that sound?
@@wingracer1614 I meant flipping it on when people are obviously trying to make content but your point still stands
@@anonymoususerinterfaceHe’s young. Typically speaking, the younger you are, the higher frequencies you can hear.
From the waveform, it does seem to cover the real signal well. But that’s not very important. Did you guys try to do a Fourier Transform to see if you can filter out the jamming and reconstruct the actual speech?
Funny stuff! Sounds like the Lander game for the Commodore VIC-20, when you hit the planet terrain and explode
I love when Linus demonstrated 'high pitched noises' his voice didn't change
I really like these deep dives on interesting tech. Even if it's not something I would ever use, just having the understanding of how it works, how the microphones are designed and how these kinds of things interact with those designs is interesting
Hey great timing I was just searching video for a dinner
Cheers, i was searching one to have lunch
^raises a glass* to the LTT dinner party
you shouldn't eat videos for dinner bro, they don't really have any nutritional value.
have good dinner bro hello
@orlagh277 Has a point, I heard the portions they serve are byte-sized...
Edit: I'll see myself out now.
I forgot how much of a menace beardless Linus could be
exposure to mobile jammer radiofrequency radiation for as little as one hour can negatively impact human hearing, especially at frequencies of 1000 and 2000 Hz. Other studies have also suggested that jammer usage may have adverse health effects on humans, including:
Brain tumors: Excessive use may increase the risk of brain tumors
Cognitive performance: Jammers may interfere with cognitive performance
Other adverse effects: Other adverse effects include headaches, fatigue, and skin irritation
As a follower since 2010. Come along way since doing motherboard unboxings.
we are getting raided with this one!🔥🗣️🥶🥶
How would it sound to someone wearing hearing aids? I wear them and if this affects microphones, I imagine that I would be able to hear it then
I love that the jammer actually makes that noise on the recording. At first I thought they just added it in.
I knew Elijah is the best in his own ways, keep it up bud!
Actually it's pretty amazing how well this thing seems to work. You expect kind of nothing from Aliexpress but this would work in many situations. Even just as an 'additional layer of protection' for secret meetings. It's not failproof sure, but this combined with already existing measurements would be an incridible extra to have. They seem to have put a lot of work and thought into it, impressive.
5:24 "-and that's how King Crimson works!"
All glory to the HypnoToad!
Wow cool comme- ALL GLORY TO THE HYPNOTOAD!
Mr. Robot used a similar device to avoid being recorded when they knew the room is being bugged.
Really flexing that Lumafield xray machine. I'm not complaining, it's awesome
About the Quebec joke .... LTT is one of my main ROC content .. just acknowledging Quebec existence is nice to ear... even in this circumstances. Et oui on va peut être décalisser, vous laisser tout seul avec Toronto!
4:31 linus enjoyed this too much xD
He looked so proud of himself
I love the MKBHD shoe "remark"!! Too funny 🤣
what was it tho , i couldn't make it out
@@KatikeyaSawai His sneakers he's selling
@@dragon2knightno they meant what did he say about them?
@@daultonvenglar9905 He didnt say anything, lol, look at the video, it was about his review of them....sigh...
@@dragon2knightYou're not the sharpest cookie are you
Could these cause hearing damage? It still vibrates your eardrums right? You just can't hear it?
Possibly. Hard to say without knowing exactly what it's transmitting and at what power level. But yes, that is a possibility.
possibly, even if you don't even hear it. And then you don't know to exit the room.
this is easily my favorite ltt video in a long time
This is useful for in-person conversations only. Phone conversations will obviously not be affected, unless you want the person on the other end to not hear what you're saying.
I don't really ever comment, but I really liked this video, especially the balance between technical stuff and the real world implications. Great job and please do more of the deep dive tech stuff in the future. Love it.
If you are reading this I hope you have an awesome rest of the year ❤
That would hurt my ears SO bad, I can hear 20kHz, I guess I'm a "superhuman"!
Until you get old, that is...
@@Tehn00bA true 😂
For now. I can’t hear the thermometer beeping when it’s finished now
Lying in the Internet is fun
@@MrHXCPancake i'm SLIGHTLY lying... comment edited to be 100% true
As an audiio engineer & total nerd this is probobaly my favorite LTT video.
Linus, the spectrograms were interpreted incorrectly. The spectrograms you showed were more than likely aliasing, or wrapping, in the frequency domain. A big tell is the repeating zigzag patterns. You'd need a wider bandwidth in your spectrum to capture the actual signal, assuming that it is a continuous waveform. Try doing a fft on a longer record length to produce a single spectrum. My gut feeling is that there is in fact, a strong low frequency signal, in addition to different harmonics that resonate with mic membranes.
you should look at the speech jammer made by Benn Jordan its very interesting and its similair to how this works in the way that we cant hear it but microphones can as it covers the whole spectrum
Cant wait for someone to sneak one of these into a music concert :)
“it’s legal” famous last words
It’s legal…for now 😢
Classic Canadians:
It's never a war crime _the first time!_
I read the title as "Illegal", otherwise I never would have watched this video, lol, although I did rather enjoy Linus's antics....
I love how Linus said high pitch noises and didn't change his pitch but did so for low pitch noises.