# How an Ultrasonic Sound Beam Creates Directional Audio - Original post: https://www.twitter.com/i/status/2120159543611044226 - Source account: [@maximumpain333](https://x.com/maximumpain333) - Source language: English - Duration: 2:15 - Published: 2026-11-11 - Canonical URL: https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio ## Transcript [0:00](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio) You can't hear this. It's, it's going ... [0:02](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=2) I haven't turned it on yet. When I do, it's gonna blast out a 65 kilohertz beam. [0:06](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=6) Because the wavelength is so small, it doesn't spread, because 65 kilohertz has a wavelength like that. [0:12](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=12) So it's gonna be, in that sense, similar to a laser. [0:15](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=15) It just comes right out as a beam. Now, how do we make that audible? [0:19](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=19) Well, they put a modulation on top of the 65 kilohertz. [0:22](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=22) There's the modulation. And now, here's the next thing I have to tell you, that 65 kilohertz is very high amplitude. [0:29](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=29) It won't hurt you. We don't- You certainly can't hear it, and we don't think it'll hurt you. [0:35](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=35) And, um, it's very high amplitude. And what happens when you have two sound waves like this, sound plus sound can create sound, but only at high amplitude. [0:44](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=44) At low amplitude, sound waves just travel right through each other. [0:48](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=48) You may be sort of familiar with this. But at high amplitude, you can create sound. [0:52](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=52) So what happens in this apparatus is the audio sound, the sound that you're gonna hear, is actually created in the beam, not here. [1:00](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=60) And because it's created in the beam, s- it stays in the beam. [1:04](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=64) We have a beam of sound. So let me demonstrate this for you. [1:06](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=66) Let me turn it on, and I'm gonna find the piece of music that we like. [1:11](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=71) Yeah. Now, you may not like it but ... The Eagles? [1:15](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=75) You like the Eagles? Yes. Yes. Okay, good. [1:17](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=77) Oh, we have a, we have a friendly audience this year. [1:19](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=79) Yeah. Eagles. I think they're just saying it to make us feel better. [1:22](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=82) Right. All right. [1:32](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=92) What? Wow. It's worth the $2,000. It's not your, it's not our money. [1:40](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=100) Now- Can you hear it? ... the sound that you're hearing is being created in this beam. [1:45](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=105) It, it almost sounds like it's coming from your head. [1:47](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=107) So let me, let, let me try to scan the whole audience just so everybody gets to hear this. [1:52](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=112) Absolutely remarkable. [1:56](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=116) Can ... Are you getting it? [2:06](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=126) Let's try to ... Wait, one more thing. Let's try to bounce it off a wall. [2:10](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=130) Raise your hand if you can very clearly hear it. [2:13](https://www.translate.mom/transcript/pH18yEfTEhVM/en/how-an-ultrasonic-sound-beam-creates-directional-audio?t=133) I'm gonna try to bounce it off the wall.