translation.en: An effect happens in the air, it's a corrupting effect of the sound -- the ultrasound in this case -- that's emitted, but it's so predictable that you can produce very precise audio out of that effect.
translation.zh: 它也作用于空气，但是是相反的效果 这就是特超声 但是它是可预测的 你可以制造精确的广播来消除这种影响