Clearly we should build two of these and have them respond to each other.
A Burroughsian modification would be to have it recording on a loop and immediately play back their voice at high volume
That Bob Widlar was quite a characterâŚ
Nice and elegant in its simplicity.
Idea. There are highly directional ultrasound-based speakers that project intersecting ultrasound beams that interfere into audible sound. A nice trick could be taking the ambient sound that annoys you, running it through a delay line of a few hundreds to thousands milliseconds, and playing it back to the location where it will annoy the most. When the target switches off their sound production, the counterannoyer will cease sending signal too.
This could be used for great fun for politicians and other big cheeses having public talks. Play their own speech back to them with a slight delay (âdelayed auditory feedbackâ). Example here.
This will be inevitably used against protesters trying to talk, anyway; being the first ones (for change) who uses this against the Powerful People would be nice.
These people must be really obnoxious to be around.
I can accomplish the very same thing with my mouth. Maybe itâs not as high tech, but my reaction time is unbeatable.
A device to blow the fuse to the stereo, close the windows, and lock the doors when someone leaves their car unattended with the stereo blaring at a gas station would be very helpful.
I donât know if theyâre actually being used yet, but a weaponised speech jammer does exist:
Christ, what an asshole.
Oh. Time for countermeasures then. If possible, from commonly accessible components, capable of being rigged in minutes or less.
Try out if speaking while listening to loud music that overpower this would help. Or with just those earplug headphones, unplugged, that attenuate the sound.
Or a throat mic, or sufficiently close-to-mouth mic, feeding the headphones with oneâs own amplified speech. Maybe the same could be achieved with a phone handsfree and a suitable app that takes sound from the mic and sends it to the headphones (and filters eventual feedbacks with an adaptive notch filter)?
The test can be done with a conventional speaker, loud enough. No need to maintain the directionality nor distance, so the cost/availability of the ultrasound rig can be avoided for testing purposes.
I once âinventedâ a device that would replace the âurbanâ music with Barry Manilow. (In a short story, fictionally).
But this device could be a total marriage saver.
Also, in the department of old hacker stories: A friend wrote one of these as a Mac system 6.x extension, called âConan the Librarianâ â any time the ambient sound in a room was too high, a cartoon figure appeared and said âShhh!â If the ambient level stayed too high, or went to a really high volume, it would yell, âHEY, KEEP IT DOWN!â
Of course, the first order of business was to install it in a lab full of machines so all the Conans could keep each other company 
I once had a great idea for a device, but I moved house where I needed it before I got around to building it. It would have some filters, so as to be able to be tuned to be fairly selective for triggering when a dog barks, and would have a super high intensity, directional, piezo horn blasting white noise with a high pass filter cutting everything below 20kHz. For when your asshole neighbor wonât do anything about their dobermans that sit there in their yard and bark constantly all day while theyâre away.
IMO anyone who contributes that much to humanity is allowed a few personal flaws.
I was really hoping when reading the headline that this was a device that actually stuns (i.e. either electrically or pharmacologically) noisy people⌠I can yell at noisy people, or carry an air horn or something similar.
With their hippinâ and their hoppinâ, and their bippinâ, and their boppinâ
I have one of these. It took a while, but it finally worked.
ââIf you have neighbors with a noisy barking dog, you could use the output from the Noise Protest Device to retaliate by triggering an ultrasonic transducer.ââ
This is a good idea, is entirely fair play, and doesnât hurt the dog any.
Iâd prefer to combine this:
With a white noise device. If the laser is pointed at something closer to the object of the noise, it could effectively cancel it out (within reason).
