If you watch closely enough, everything is a speaker • Hacker News Board

Re: If you watch closely enough, everything is a speaker

#51

Post by totalZero » Sun, Jan 28, 2018, 6:01 AM UTC

blincoln wrote: post #48

nwatson wrote: post #33

Impeached Arizona governor Evan Mecham (shortened term 1987-1988) was probably very paranoid during his time in office, but nobody gave credence to his concern over the possibility of "reflected laser use" to surveil him. From Wikipedia ( https://en.wikipedia.org/wiki/Evan_Mecham ) ... Throughout his administration, Mecham expressed concern about possible eavesdropping on his private communications. A senior member o…

No one took him seriously because "I always have a radio on. It keeps the lasers out." is a textbook example of the kind of thing someone experiencing paranoid psychosis will say. i.e. there are certainly listening devices that operate based on bouncing a laser off of a window[1] (or some other object), but his use of a quasi-magical protective measure (radios allegedly protecting against lasers) - in addition to the…

Is he wrong? Adding noise from a radio or TV in the room may be an effective way to obfuscate attempts to use laser reflection surveillance on a window or other diaphragm. Both the device and the person speaking will cause the laser to jitter as the window vibrates.

Re: If you watch closely enough, everything is a speaker

#52

Post by bagacrap » Sun, Jan 28, 2018, 7:15 AM UTC

"everything is a speaker, especially earbuds!" That example doesn't seem particularly noteworthy.

Re: If you watch closely enough, everything is a speaker

#53

Post by CharlesW » Sun, Jan 28, 2018, 7:48 PM UTC

mannykannot wrote: post #29

fit2rule wrote: post #28

Disclaimer: I work for a professional microphone manufacturer. I wonder how long it'll be until this technique becomes feasible for recording professionally? Like, instead of capsules and diaphragms, we just have a laser that gets the cleanest, clearest possible signal it can, from the room around you ..

Isn't one of the benefits of high-quality microphones that they can reject or attenuate the ambient sounds and reverberations that you do not want?

Higher-quality microphones tend to pick up more ambient sound because they're more sensitive and/or have a larger frequency response.

"Worse is better" sometimes applies to mics as well. For example, new podcasters are often advised to use cheap dynamic mics since it forces them to get close to the mic (improving their signal-to-noise ratio) and doesn't pick up audio over 15 kHz (which is not meaningful for voice recording).

Re: If you watch closely enough, everything is a speaker

#54

Post by mannykannot » Mon, Jan 29, 2018, 2:14 PM UTC

CharlesW wrote: post #53

mannykannot wrote: post #29

Earlier quoted context omitted.

Isn't one of the benefits of high-quality microphones that they can reject or attenuate the ambient sounds and reverberations that you do not want?

Higher-quality microphones tend to pick up more ambient sound because they're more sensitive and/or have a larger frequency response. "Worse is better" sometimes applies to mics as well. For example, new podcasters are often advised to use cheap dynamic mics since it forces them to get close to the mic (improving their signal-to-noise ratio) and doesn't pick up audio over 15 kHz (which is not meaningful for voice rec…

more sensitive and with a wider frequency response but also directional and with fewer resonances than what OP was suggesting.