字幕表 動画を再生する 英語字幕をプリント So you've heard of white noise? Did you know that was pink and blue noise on? Indeed, Perhaps green noise on red noise and a whole range of other noises. Where did all those different colors come from? And what is white noise anywhere? Hiken noise. Have a color? Yes. Oh, I could just do it here. There we go. Yeah, OK, that's white noise. So that's the sound off a signal which has absolutely no period is city to it. It's entirely an orderly random. Why do we call it white noise when we call it white noise in an allergy with spectrum with spectrum of light from a rainbow, for example, or any type of specter. So all frequencies contribute equally so, just as you have with white light. All colors contribute equally in this case or frequencies. What does that mean? Well, you can think of a wave unaware varies in time. So if it's Varian with a slow frequency, it's changing on slow time scales, and it's not very rapid, but then you can also of high frequency waves. Also it back and forth very, very quickly. So different. Sabrina. That's what I'm talking about. You mix those all together all those different frequencies from the very, very slow to the very, very high, and you mix them all together equally on what you get is white noise. So what you're hearing was, ah, sample of white noise, which has been generated very simply on a computer which covers frequencies from very, very low, close to zero hurts all the way up to about 20 kilohertz. Something like that. And it's an equal mixture of all those frequencies. And that's what this is showing us is showing us the power associated with each frequency. And so you mix it all up so all the powers contribute equally, and what you get is white noise. So that suspect in for white nights. So just as we have, you know, if you've a pink color or a red color or a blue collar in terms of light, it means that certain frequencies air dominating, certain wave and certain frequencies of dominating. If you've got pink noise, then what you have is the lower frequencies which are moving towards the red end of the spectrum are contributing Maur. So if we look at a spectrum for pink noise, you hear any difference at all was that what was that supposed to be? Level is so well, it's no, it's that's meant to be pink noise. So it's going to be different from white noise. Can you hear any difference? Well, we play the two back to back and see if you can hear any difference. Can you hear that? Lower frequency rumble? It's deeper. It is. It's deeper. That's what we'd expect because in this case, when we look at the frequency spectrum, then what we find is instead of it being flat, it tails off. And so what we have is the lower frequencies contribute Maur than the higher frequencies. So we hear that rumble and in fact, the one over after noise. If you listen to it again, sense rather like rainfall much and being sitting inside the unison of the rain outside. You just won with Griff? Yes. Did I just say one over? OK, yeah, So that's how the frequency spectrum goes. So the power in this case goes inversely with the frequency. So as we're going open frequency, the power is dropping down. So it goes as worn over F. Well, they're white noise is no dependence, so no depends on frequencies, so it's a constant. So it's flat. So But we can also have Blue Nice and you can probably guess what blue noises that's not blue. Nice. Yes, that's certainly got a periodic told hello with one over F so it falls off with frequency, so it's inversely dependent on frequency. If we have blue noise, then you probably can guess what it's going to do. But let's have a listen to blue noise. First of all, Theo Thief power Last time was proportional toe one over efforts. It was falling off with frequency. Now it's proportional to afterwards, growing with frequency on it's exactly the same. So what we're doing with one over f is word waiting it towards the lower frequencies. Getting red are getting Pinker. What we're doing now is we're waiting it towards higher frequencies getting blue. When I think of white noise, I think that fuzz on the TV What's that? That's exactly that's a visual representation of what we're hearing here in terms of exactly the same idea where we get a great deal off frequencies all contributed together. Once we have all those frequencies contributing so we don't have a spectrum of the ramp like it on this, where it's a flat spectrum. We call out white noise in some cases, depending on the equipment you have and depending on the type of setup you have and depending on how your aerials working, you might have deviations from white noise. But you're white. Noise means that you have gone out of everything, contributing to the same extent. You've got a lot of websites saying that what you should do is fall asleep with pink noise because it gives you a more sort of harmonious Bree in rhythm. There seemed to be some papers that makes suggestions along those lines. I'm not entirely convinced. I've got to admit, I must admit that part of me thinks that what we should do Brady is just record a lot of white noise and pink noise and blue noise and send it out there in charge, charge a little bit of money for it. I think way could set up a business very quickly. Black noise, You always Oh, that's interesting to raise. Indeed, there is even black noise. There is black noise, so I know exactly that's exactly what it is. Black noise is an absence of any noise at all. It's, but it's even to find. You can find a wicky entry on black nose, which I didn't even realize until very recently. That's what we should do. So there is that considered a reason there's that. That's a piece of classical music. You are meant to be classical, which is like a time for 30 tourist on the original silence. Just pure silence. That's what it is. I think it's called John Cage. Isn't there something ironic that, like, you know, heavy metal people wear black and yet black knows this silence? No, that's good. Yeah, absolutely. And that's because we interact with. Ultimately, it's because we interact with our environment, and that doesn't require consciousness.