I Bought a Recording Jammer. It’s Legal.

[JordB]

 

With this Ultrasonic Recording Jammer, Linus can finally speak his mind! Of course, he was already doing that..

 

Some light reading about ultrasonic jamming:

https://synrg.csl.illinois.edu/papers/backdoor_mobisys17.pdf

https://people.cs.uchicago.edu/~ravenben/publications/pdf/ultra-chi20.pdf

https://counterespionage.com/ultrasonic-microphone-jammers/

https://arxiv.org/pdf/1904.08490

[Mikro 7]

OK Linus The connecter papers are looking good where is your test results , the documentation?

[Space646]

Do YOU  like cats?

[dragon_iroh]

As someone wearing hearing aids (more specifically cochlear implants) it would be interesting to know how my "hearing" would react to that jammer. Let me know if you tried that... Very interesting technology tho

[Sparky221438]

I'm curious if you could take the device apart and grab the sound from it and upload it to youtube or upload a link to test if it will work with a Bluetooth speaker?

[GoStormPlays]

Hot take:

 

Apple is #$*(&@):$%*$_*&!^^@%#&^^)$_*(%

[MeowDude]

Dear Linus,

 

Please tell me what you said in the video. I would be really grateful if you did. I won’t tell anyone. I promise.

 

Sincerely, MeowDude.

[FlyingPotato_is_taken]

Interesting that the professional microphone was able to pick it up. Normally the flush part on top is enough to block the ultrasound.

This isn't a big limitation as the primarily defence is against tiny spy devices recording and they still lack protection for one reason or another. Similar smartphones don't have those measures in place either.

 

For the noise/hearable sound moving it towards 40kHz is possible but poses new challenges (efficacy/sound pressure). Similar there are harmonics at half the audio frequency that are in the hearable range. Pushing towards higher frequency's mean that the first harmonics is still outside the human hearing range. As those devices aren't perfect they don't produce just one frequency at somewhere in the 20-29 kHz but a range of frequency's that can reach into the human hearing capabilities.

 

 

9 hours ago, Sparky221438 said:

I'm curious if you could take the device apart and grab the sound from it and upload it to youtube or upload a link to test if it will work with a Bluetooth speaker?

Won't work.

1.) pressure level are order of magnitudes higher than a Bluetooth speaker

2.) the driver within the Bluetooth speaker can't drive at these frequency's

3.) the speaker that are in these boxes won't be able to produce noticeable pressure at these frequency's.

 

Internally there is likely multiple piezo driver. Likely a h-bridge configuration.

[Elemino Musgrove]

I'm curious about the effect this has on people with hearing aids and how a ribbon mic would react to it.

 

No surprise on the short shotgun mic, I bet a long shotgun mic would do even better.

 

I'd like to have one, but as someone that could always tell when a CRT was turned on in a room, or when AC capacitors were doing something strange, I'd probably be one of those people driven crazy by the sound.

[Skyfighter]

Is it possible to get the raw test recordings from the video with/without the jammer somewhere? I'd like to play around a little bit and test some ideas if the noise could be reduced or removed in software.

[Brian McKee]

Even if you can't hear it, it can still damage your ears.

[sub68]

On 4/27/2024 at 11:45 PM, Elemino Musgrove said:

No surprise on the short shotgun mic, I bet a long shotgun mic would do even better.

They only have access to a 416 which those are pretty good but yeah something like rode ntg 8 would be intreasting.

On 4/27/2024 at 11:45 PM, Elemino Musgrove said:

how a ribbon mic would react to it.

IMO it would still pick it up because it still gonna vibrate the element.

[FlyingPotato_is_taken]

On 4/29/2024 at 2:03 AM, Skyfighter said:

Is it possible to get the raw test recordings from the video with/without the jammer somewhere? I'd like to play around a little bit and test some ideas if the noise could be reduced or removed in software.

Depends on the implementation. 

If it is just a constant  ultrasound tone you could post process it to get it original audio/conversation.

Assuming it is a little bit more advanced you can't. Them using this sawtooth shape shown in the video is one of the approaches that are required.

 

This topic is a little bit more complicated. It is also possible to manipulate the audio recording. In other words you emit a ultra sonic sound and the MEMS mic will pick up a voice/conversation in the hearable audio range.

 

 

Similar those ultra sonic devices won't protect against laser microphones. Another frequently used attack vector.

[Brian McKee]

On 4/30/2024 at 1:26 PM, sub68 said:

 

IMO it would still pick it up because it still gonna vibrate the element.

I'd be concerned such aggressive wave generation could damage some more fragile ribbon mics.

[sub68]

4 hours ago, Brian McKee said:

I'd be concerned such aggressive wave generation could damage some more fragile ribbon mics.

I would too...

[Uttamattamakin]

Yes, Quebec should leave Canada already.  It will make them all the easier to annex as the state of North Louisiana later.