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While technically true, in most real life situations, this is not possible to exploit. If the speakers have an amplifier in line with them, they will not work i

While technically true, in most real life situations, this is not possible to exploit. If the speakers have an amplifier in line with them, they will not work in reverse. If the speakers are built in to a laptop, the driver circuitry will not allow them to work in reverse. Pretty much the only way this might be possible is if you had an audio port that was capable of functioning as both a TRS output and a TRS input (not a TRRS "headset" port), and had a set of headphones plugged into said port, and had a piece of malicious software that was able to reconfigure the port to act as an input.

WalterBright 5y ago
When I was a boy I'd hook up a speaker to a phono input, which made a great PA system! An even longer wire attached to the phono input turned any amplifier into an AM radio. A simple intercom is just two speakers, one on each end, wired together in a loop.
- pengaru 5y ago
  Nice! In my childhood I took apart a broken WalkMan and discovered if I connected a random ~8" loudspeaker driver in the tape head's place, I could eavesdrop on my siblings and parents from across the house by placing the speaker against the walls or floor, complete with volume control and everything. It was incredibly sensitive, and infuriating to learn how much everyone was constantly lying and talking behind eachother's backs at that age.
gruez 5y ago
>and had a piece of malicious software that was able to reconfigure the port to act as an input. That's actually a feature of many realtek sound drivers. https://www.reaper-x.com/2012/02/13/how-to-remap-retasking-realtek-onboard-jacks-ports/ https://www.reaper-x.com/2012/02/13/how-to-remap-retasking-r...
orbital-decay 5y ago
>Pretty much the only way this might be possible is if you had an audio port that was capable of functioning as both a TRS output and a TRS input Most embedded PC sound cards made in the last few years have this. (also, you'll need headphones without an amplifier as well!)

WalterBright 5y ago

When I was a boy I'd hook up a speaker to a phono input, which made a great PA system! An even longer wire attached to the phono input turned any amplifier into an AM radio. A simple intercom is just two speakers, one on each end, wired together in a loop.

pengaru 5y ago
Nice! In my childhood I took apart a broken WalkMan and discovered if I connected a random ~8" loudspeaker driver in the tape head's place, I could eavesdrop on my siblings and parents from across the house by placing the speaker against the walls or floor, complete with volume control and everything. It was incredibly sensitive, and infuriating to learn how much everyone was constantly lying and talking behind eachother's backs at that age.

gruez 5y ago

>and had a piece of malicious software that was able to reconfigure the port to act as an input. That's actually a feature of many realtek sound drivers. https://www.reaper-x.com/2012/02/13/how-to-remap-retasking-realtek-onboard-jacks-ports/ https://www.reaper-x.com/2012/02/13/how-to-remap-retasking-r...

orbital-decay 5y ago

>Pretty much the only way this might be possible is if you had an audio port that was capable of functioning as both a TRS output and a TRS input Most embedded PC sound cards made in the last few years have this. (also, you'll need headphones without an amplifier as well!)