3 ms·

This doesn’t work anymore, if it ever did. There is free software capable of isolating audio like a single voice from background noise.

• grkvlt 8y ago
  Not sure how this can't work, it's just audio jamming, same as for EM waves. You just need to broadcast sufficient noise to cover the signal, i.e. the S:N ratio is such that the receiver (crisp packet, microphone, etc.) can no longer see the signal above the noise floor. Now, this might mean broadcasting a loud noise signal, which could overwhelm your (or other friendly) receivers (ears, etc.) so optimal placement of the jamming noise source becomes an issue. Generally, you want it closer to the threat than you, so that distance attenuation keeps it bearable for you but still jams possible recording devices. Or, introduce high bandwidth noise vibrations into the surfaces of the area you are in, such as windows or walls. Anyway, it's very possible and in use today in secure facilities that must be protected from audio eavesdropping.