2 ms·

But if mics can pick it up, human ears will also be able to hear it.

• shakna 9y ago
  Why? Most microphones have a greater range than your ears do. Here's a StackOverflow thread [0], exploring what sounds a smartphone can hear, that a human can't. So, going with interleaving two sounds to make something the mike thinks is audible, when it isn't: Sound A is at 13khz, Sound B is at 12khz. Human ear can't receive either, so is unlikely to notice it at all. But most smartphones can actually pick up those signals, and together, get a signal at probably < 18khz, which is in the audible range. --- (Disclaimer: I'd have to investigate further to give a precise, or meaningfully correct answer, but the above outlines the theory). [0] https://electronics.stackexchange.com/questions/59157/over-what-frequency-range-can-the-microphone-of-smartphone-receive-the-sound https://electronics.stackexchange.com/questions/59157/over-w...