WEBVTT - Shh! How Soundproofing Works 0:00:04.160 --> 0:00:12.399 Give technology with tech stuff from stuff dot com. Hey there, 0:00:12.440 --> 0:00:16.360 and welcome to tex Stuff. I am your host Jonathan 0:00:16.480 --> 0:00:23.560 Strickland joining me today special guest producer, extraordinaire, musician and 0:00:23.800 --> 0:00:27.840 all around groovy dude Noel. Welcome to the show. John Fitts, 0:00:27.840 --> 0:00:29.360 an honor and a privileged to be who repeated in 0:00:29.600 --> 0:00:33.520 it was lovely. We actually recorded together yesterday for Stuff 0:00:33.560 --> 0:00:35.839 They Don't Want You to Know, which you are a 0:00:35.920 --> 0:00:38.840 host of that show co host, a co host along 0:00:38.880 --> 0:00:42.320 with the co hosts with Matt Frederick and Ben Bolan 0:00:42.960 --> 0:00:45.360 and you guys were very generous to have me on, 0:00:45.400 --> 0:00:47.720 and so I'm not as generous, so I only took 0:00:47.720 --> 0:00:49.559 one of you. That's fair. We had a good time though. 0:00:49.600 --> 0:00:52.320 We did a nice little Facebook live thing. We talked 0:00:52.320 --> 0:00:54.720 about targeted ads and got all riled up and then 0:00:54.800 --> 0:00:57.120 recorded a nice little podcast. It was fun. Yeah. So 0:00:57.160 --> 0:01:00.560 if you guys have been enjoying my series on on 0:01:00.600 --> 0:01:03.560 the problem with advertising online, you can think of the 0:01:03.600 --> 0:01:05.000 Stuff They Don't Want You To Know as sort of 0:01:05.000 --> 0:01:08.080 a sister podcast on that same topic. Some of the 0:01:08.080 --> 0:01:11.520 stuff we cover is similar, but we take a because 0:01:11.520 --> 0:01:13.680 we have three other folks in there, and it's four 0:01:13.680 --> 0:01:16.400 people total. It ends up having a lot of different 0:01:16.440 --> 0:01:18.399 viewpoints and a lot of discussions, and we tend to 0:01:18.480 --> 0:01:20.640 go a little dark at times. Yeah it does. It 0:01:20.680 --> 0:01:23.560 gets a little dark, um, but also fun also light. 0:01:23.680 --> 0:01:25.120 You know, it's not all the dark, suff I mean, 0:01:25.160 --> 0:01:28.479 it's it's it's life, right. So one of the things 0:01:28.480 --> 0:01:29.840 I like to do on this show is at the 0:01:29.920 --> 0:01:33.040 end of every episode, I invite you guys to send 0:01:33.080 --> 0:01:38.880 me requests ideas topics for future episodes. And today's episode 0:01:39.200 --> 0:01:42.000 is due to that. So I'm going to read a 0:01:42.080 --> 0:01:48.560 little bit of listener mail. You know, we used to 0:01:48.560 --> 0:01:51.360 have a whole claxon all right, here he goes, Hey 0:01:51.400 --> 0:01:53.680 you tech stuff. First off, I want to thank you 0:01:53.720 --> 0:01:56.000 for putting out your content as I'm a huge fan 0:01:56.120 --> 0:01:59.080 of this casual learning movement. Might need a better term 0:01:59.120 --> 0:02:01.480 for that. I was wondering if you'd be able to 0:02:01.560 --> 0:02:05.240 do an episode on acoustics and sound dampening for studios, 0:02:05.280 --> 0:02:08.520 like how they're measured, tuned, made, etcetera. It would be 0:02:08.560 --> 0:02:11.480 awesome and spectacular as I would be able to harness 0:02:11.520 --> 0:02:13.720 the power to put together a kick ass set up. 0:02:14.040 --> 0:02:18.200 Thanks again for what you do. Dub Nosis well dubbed 0:02:19.200 --> 0:02:21.160 we're going to do that for you. And that's really 0:02:21.200 --> 0:02:22.959 the reason why I asked Noel to come in here, 0:02:22.960 --> 0:02:27.359 because Noel, as a producer and sound engineer type person, 0:02:27.520 --> 0:02:31.880 has had real world experience with this, and so we're 0:02:31.919 --> 0:02:36.240 going to rely heavily upon his um perspective some of 0:02:36.280 --> 0:02:38.720 the stories he has to tell about the process of 0:02:38.760 --> 0:02:42.600 trying to make a room more soundproof or tuning a 0:02:42.720 --> 0:02:45.679 room so that you're getting the sound you want while 0:02:45.720 --> 0:02:48.320 you're recording, because, as it turns out, sound is a 0:02:48.440 --> 0:02:54.440 pretty tricky thing when you boil it down. Sound is vibration, right, 0:02:54.520 --> 0:02:57.760 It's just particles banging together. It's a whole thing you 0:02:57.840 --> 0:03:00.760 gotta wrangle. It is a thing you gotta wrangle. We 0:03:00.840 --> 0:03:05.000 often consider sound to just be this thing we perceive 0:03:05.120 --> 0:03:08.400 with our ears, but what's really happening is a little 0:03:08.440 --> 0:03:13.960 more granular than that. Sound is particles that are moving, vibrating. Uh. 0:03:14.240 --> 0:03:17.960 Typically we're hearing things that are coming through over the air, 0:03:18.280 --> 0:03:21.760 like actual air around us. So you listening to this 0:03:21.919 --> 0:03:25.840 right now, you can hear my voice. Well, what's actually 0:03:25.880 --> 0:03:29.760 happening is that some speakers are vibrating some air molecules, 0:03:29.880 --> 0:03:34.079 and that is compressing and decompressing those molecules. It's it's 0:03:34.160 --> 0:03:38.200 changing the pressure, increasing and then decreasing the pressure at 0:03:38.480 --> 0:03:41.560 frequencies and amplitudes that your ears pick up and then 0:03:41.600 --> 0:03:45.600 you perceive a sound. So this is happening through all 0:03:45.640 --> 0:03:48.200 sorts of media, not just air. It can pass through 0:03:48.240 --> 0:03:51.000 solid matter, it can pass through liquid and depending on 0:03:51.040 --> 0:03:53.640 how the particles are packed and the space between them, 0:03:53.720 --> 0:03:57.720 sound may move better through one medium than through another. Now, 0:03:59.240 --> 0:04:02.320 knowing that sound can travel through different media, you also 0:04:02.360 --> 0:04:05.320 need to know that it can transfer from one medium 0:04:05.320 --> 0:04:09.240 to another medium. So for example, if I'm shouting really, 0:04:09.320 --> 0:04:13.000 really loudly in a little room, some of that sound 0:04:13.080 --> 0:04:16.440 when it makes contact with the wall, actually causes the 0:04:16.480 --> 0:04:19.440 wall to move. Now it's not causing the wall to 0:04:19.480 --> 0:04:22.599 move a lot, but it is making the wall vibrate 0:04:22.600 --> 0:04:25.800 a little bit. Those vibrations get transferred through the wall 0:04:25.839 --> 0:04:28.800 to the other side. And that's why if you're in 0:04:28.880 --> 0:04:31.840 a place that has, you know, flimsy walls, you can 0:04:31.880 --> 0:04:35.280 hear someone in another room. The sound is actually transferring through. 0:04:35.440 --> 0:04:38.360 Not to mention in the room itself, that sound is 0:04:38.400 --> 0:04:40.880 actually reflecting back at you, and the quality of the 0:04:40.960 --> 0:04:44.000 sound can depend. You can very greatly depending on the 0:04:44.000 --> 0:04:46.240 material that the room is built out of or treated 0:04:46.240 --> 0:04:49.560 with right, right, So some of the sounds getting transferred 0:04:49.640 --> 0:04:51.719 through the materials, some of the sound is being bounced 0:04:51.839 --> 0:04:55.160 back from the material toward you, um. And a lot 0:04:55.160 --> 0:04:58.600 of that depends upon the the hardness of the material, 0:04:58.680 --> 0:05:00.920 Like a really hard materials and bounce a lot more 0:05:00.960 --> 0:05:03.280 sound back at you, which is why if you are 0:05:03.320 --> 0:05:06.320 in a large room with a lot of hard surfaces 0:05:06.360 --> 0:05:09.599 you get that echoe sound. Um. Or if you're out 0:05:09.720 --> 0:05:12.760 someplace like at a canyon and you do a shout 0:05:12.800 --> 0:05:14.760 and you get that echo back, it's because the sound 0:05:14.839 --> 0:05:18.680 is going out hitting the walls of the canyon, bouncing 0:05:18.720 --> 0:05:21.240 back to you, and that's when you get to experience 0:05:21.600 --> 0:05:26.760 that effect. Well. Obviously, this means that if you want 0:05:26.839 --> 0:05:32.479 to create a place where the sound can't escape or 0:05:32.600 --> 0:05:36.000 leak into and a lot of recording studios, you want 0:05:36.000 --> 0:05:37.919 both of those things right. You don't want the sound 0:05:37.960 --> 0:05:40.640 from the studio to leak outward, but you also definitely 0:05:40.680 --> 0:05:44.600 don't want outside sound to leak into the important Then 0:05:44.640 --> 0:05:46.760 you have to figure out, well, how do we limit 0:05:46.800 --> 0:05:51.120 how do we work within the physical uh uh constraints 0:05:51.640 --> 0:05:54.080 of the way sound works, so that we can limit 0:05:54.120 --> 0:05:56.440 that as much as possible and try to have the 0:05:56.480 --> 0:06:02.440 purest experience as we can. Uh So, one thing you 0:06:02.480 --> 0:06:06.919 can remember is that sound, because it's a physical activity 0:06:07.040 --> 0:06:10.279 and because it relies on on energy, the way it 0:06:10.320 --> 0:06:12.400 works is that you've got a source of the sound. 0:06:13.080 --> 0:06:18.240 Sound waves travel outward concentrically outward from that source, and 0:06:18.279 --> 0:06:21.200 they get weaker as they travel out that that energy 0:06:21.360 --> 0:06:23.520 starts to dissipate. You can think of it kind of 0:06:23.520 --> 0:06:27.080 like um uh, you know, each each time a particle 0:06:27.120 --> 0:06:29.479 has to bang up against another one to move it, 0:06:29.880 --> 0:06:32.080 some of that energy ends up getting lost. So the 0:06:32.120 --> 0:06:33.919 further way you are from a source of sound, the 0:06:33.960 --> 0:06:37.000 quieter it is. That's why that happens. So one way 0:06:37.040 --> 0:06:40.080 you can limit the way sound comes out of a 0:06:40.160 --> 0:06:43.080 room is you make an enormous room like you have 0:06:43.120 --> 0:06:47.159 a little room in a really big room. Um. But 0:06:47.279 --> 0:06:50.279 that's not necessarily the most practical approach. Actually, there's a 0:06:50.279 --> 0:06:52.920 studio I used to intern at in Athens, Georgia called 0:06:53.000 --> 0:06:57.640 Chase Park Transduction, and they essentially built their studio inside 0:06:57.680 --> 0:07:00.880 of a larger warehouse space. So they're renting a space 0:07:00.920 --> 0:07:04.200 in the strip of big giant, very high ceiling warehouse spaces. 0:07:04.240 --> 0:07:07.599 But when you go into the studio, you're in the warehouse. 0:07:07.839 --> 0:07:13.000 But then there's a smaller basically building inside that warehouse 0:07:13.240 --> 0:07:16.200 that is the one that receives all the acoustic treatments. 0:07:16.200 --> 0:07:18.120 But it's like you said, I mean that is one 0:07:18.160 --> 0:07:21.240 way of dealing with it is air. Yeah, the room 0:07:21.280 --> 0:07:24.280 within a room approach is often how it's referred to, 0:07:24.480 --> 0:07:27.240 and sometimes it is not as obvious as that. Like 0:07:27.320 --> 0:07:31.240 it may be that it looks like the the room 0:07:31.240 --> 0:07:33.240 you're walking into might be like it's it's in a 0:07:33.280 --> 0:07:37.320 little uh alcover hallway, but that hallway is actually showing 0:07:37.440 --> 0:07:40.080 where the the walls are, where there's an air gap 0:07:40.240 --> 0:07:43.640 between the two walls to to mitigate any sound coming 0:07:43.720 --> 0:07:46.920 into the space. Even this glass window that we have 0:07:47.000 --> 0:07:48.840 in the booth that we're recording in right now, it's 0:07:48.880 --> 0:07:52.480 a double paned window, So in between these two relatively 0:07:52.520 --> 0:07:54.960 thick pieces of glass is a little layer of air, 0:07:55.280 --> 0:07:57.360 which in and of itself acts as a bit of 0:07:57.400 --> 0:08:01.440 a sound dampening insulation device, right exactly, So, uh, some 0:08:01.480 --> 0:08:03.720 other little elements of sound that we need to remember. 0:08:04.360 --> 0:08:08.600 There are two main components to a sound wave. That 0:08:08.680 --> 0:08:11.800 are important to keep in mind. One is amplitude or volume. 0:08:12.240 --> 0:08:15.800 So if you are looking at the way we typically 0:08:15.960 --> 0:08:17.840 show a sound wave which is on like an X 0:08:17.960 --> 0:08:21.160 versus Y graph um you know those those sine wave 0:08:21.280 --> 0:08:25.320 style graphs, the height and depth of the troughs that 0:08:25.400 --> 0:08:29.160 represents the amplitude how loud the sound is. Then you 0:08:29.200 --> 0:08:32.440 have the frequency of sound, the number of times sound 0:08:32.760 --> 0:08:37.120 cycles within a second. That determines the pitch of a sound. 0:08:37.320 --> 0:08:41.360 So a low frequency obviously would be a perceived as 0:08:41.400 --> 0:08:44.800 a lower deeper note or tone, and a high frequency, 0:08:44.880 --> 0:08:48.559 with those peaks and troughs moving gradually more closer together, 0:08:48.679 --> 0:08:52.160 is going to be perceived as a higher pitch. A 0:08:52.200 --> 0:08:53.959 good way to think about this too, is if anyone's 0:08:53.960 --> 0:08:57.000 familiar with the instrument the theoremin. There are two controls 0:08:57.000 --> 0:08:59.480 on a theoreman. One is the antenna that goes upward, 0:08:59.480 --> 0:09:01.360 and there's an end and on the side uh the 0:09:01.400 --> 0:09:03.800 antenna on the side you use your hand by moving 0:09:03.800 --> 0:09:06.800 it closer to or farther away, you are changing the 0:09:06.840 --> 0:09:09.959 amplitude and that's perceived as a change in volume. The 0:09:10.080 --> 0:09:12.520 antenna going up as you move your hand closer to 0:09:12.600 --> 0:09:15.240 it or farther away, you are changing the frequency. So 0:09:15.520 --> 0:09:19.040 with those two controls you can basically shape the way 0:09:19.040 --> 0:09:22.080 the sound is perceived. Right, And it's important to remember 0:09:22.320 --> 0:09:26.439 these things because uh, as it turns out, different approaches 0:09:26.480 --> 0:09:31.160 to sound proofing are effective for different frequencies. Definitely, right. 0:09:31.200 --> 0:09:33.600 So there might be one that you're like, oh, this 0:09:33.640 --> 0:09:36.559 is this is perfect. I can't hear my neighbors anymore. 0:09:37.000 --> 0:09:39.360 But then it turns out that when your neighbors put 0:09:39.400 --> 0:09:41.360 on a an album that has a lot of base 0:09:41.400 --> 0:09:43.960 in it, it comes right through or start yelling at 0:09:43.960 --> 0:09:46.840 each other for whatever. Yeah, the amplitude is loud enough, 0:09:46.840 --> 0:09:50.160 it maybe that you're soundproofing isn't going to be. Uh. 0:09:50.440 --> 0:09:52.559 When people yell, sometimes they tend to raise the picture 0:09:52.800 --> 0:09:54.680 right right right, the pitch goes up enough that I 0:09:54.720 --> 0:09:57.040 got you. Yeah, So these are things that you have 0:09:57.120 --> 0:09:59.600 taken to consideration if you're trying to sound proof, and 0:09:59.640 --> 0:10:03.200 obviously what you are trying to accomplish, like the reason 0:10:03.240 --> 0:10:05.760 why you're soundproofing, that will play into it as well, 0:10:05.760 --> 0:10:07.520 because if all you're trying to do is just make 0:10:07.559 --> 0:10:10.200 it quieter so that you know, you don't have like 0:10:10.240 --> 0:10:13.080 you're designing a building, maybe it's a hotel and you 0:10:13.120 --> 0:10:15.960 want to make sure that the the people talking in 0:10:16.040 --> 0:10:19.280 one room doesn't bleed over into other rooms. That's one 0:10:19.320 --> 0:10:22.239 type of soundproofing. If you're trying to make a professional 0:10:22.280 --> 0:10:26.240 recording studio, that's another type. From a construction standpoint, Like 0:10:26.320 --> 0:10:30.040 the base level soundproofing is drywall, so you have drywall, 0:10:30.360 --> 0:10:32.280 and that is where if you're in a hotel that 0:10:32.360 --> 0:10:34.360 only uses drywall, people are gonna be able to hear 0:10:34.440 --> 0:10:36.839 every single thing that's going on next door. It's when 0:10:36.840 --> 0:10:40.040 you start basically stuffing that dry wall with other denser 0:10:40.120 --> 0:10:43.960 materials or you know, highly rated soundproofing materials, that's when 0:10:43.960 --> 0:10:47.440 you can really cut down on that transfer between the rooms. Right. 0:10:47.480 --> 0:10:51.480 And also there are other some other techniques you can 0:10:51.600 --> 0:10:54.280 use as well that I'll get into that, And it's 0:10:54.320 --> 0:10:56.680 all about how do you make it harder for the 0:10:56.720 --> 0:10:59.120 sound to travel from one place to another because sound 0:10:59.160 --> 0:11:00.800 is going to travel no matter or what. It's not 0:11:00.880 --> 0:11:05.480 like we have created a material that just sucks up 0:11:05.559 --> 0:11:09.240 sound totally. We've got a lot of materials that resist 0:11:09.360 --> 0:11:12.520 vibration and that means that they don't transfer sound very well. 0:11:12.920 --> 0:11:16.680 But in fact, the studio has some of that around us. 0:11:16.720 --> 0:11:18.920 But you know, there's other stuff you have to take 0:11:18.960 --> 0:11:23.480 into consideration as well. Now, there are four general elements 0:11:23.480 --> 0:11:26.160 to soundproofing, and we've we've kind of touched on a 0:11:26.200 --> 0:11:29.120 few of them, but one of the big ones is 0:11:29.520 --> 0:11:34.439 called decoupling. Now, decoupling is a construction term. When you're 0:11:34.440 --> 0:11:38.440 talking about decoupling, you're talking about the way the walls 0:11:38.600 --> 0:11:41.839 of the soundproofed area are actually constructed. So you were 0:11:41.880 --> 0:11:44.960 just talking about dry wall. The typical way a wall 0:11:45.040 --> 0:11:48.840 is constructed if you've got studs and attached to the 0:11:48.880 --> 0:11:53.000 studs are the anchor points for the drywall. And in 0:11:53.280 --> 0:11:57.560 a typical wall, the studs are connected on either side 0:11:57.720 --> 0:12:00.000 by drywall for one side of the wall and dry 0:12:00.000 --> 0:12:01.599 wall for the other side of the the wall. So the 0:12:01.960 --> 0:12:03.800 uh and if you can think of it like the 0:12:03.800 --> 0:12:07.440 interior wall versus the exterior wall of a room. The 0:12:07.480 --> 0:12:10.520 problem with that is that when sound hits the drywall, 0:12:11.080 --> 0:12:14.319 then sound can travel through the dry wall through the studs, 0:12:14.520 --> 0:12:17.520 which transmit sound. They're a pretty good conductor for sound 0:12:17.880 --> 0:12:19.800 to the other side of the dry wall, and then 0:12:19.840 --> 0:12:22.600 you get sound bleeding out or you have sound bleeding 0:12:22.600 --> 0:12:27.080 in from the outside. So decoupling is a process where 0:12:27.160 --> 0:12:30.760 you would build a wall so that the studs don't 0:12:31.600 --> 0:12:34.480 touch both sides of the wall. You would have a 0:12:34.520 --> 0:12:37.400 series of studs that one side the interior wall are 0:12:37.440 --> 0:12:40.240 attached to, and a different series of studs that the 0:12:40.280 --> 0:12:44.600 exterior wall are attached to. They both extend well into 0:12:44.760 --> 0:12:47.960 the gap between the two walls, but they don't touch 0:12:48.040 --> 0:12:51.160 the other side. So one side could be receiving sound 0:12:51.160 --> 0:12:55.079 waves and potentially transfer those, but since they're not touching, 0:12:55.600 --> 0:12:57.679 it's much more difficult for that to happen, right, because 0:12:57.720 --> 0:13:00.200 air is not as good a conductor of sound as 0:13:00.200 --> 0:13:03.319 a solid object is, which you wouldn't think that, because 0:13:03.360 --> 0:13:05.000 I mean, here we are in a room talking to 0:13:05.000 --> 0:13:08.520 each other, and the air is basically what's connecting us. 0:13:08.800 --> 0:13:10.840 But the interesting thing, though, is that the way you 0:13:10.880 --> 0:13:13.080 can tell this, it's very easy way to tell. It's 0:13:13.120 --> 0:13:16.000 the old kid game of a telephone where you get 0:13:16.000 --> 0:13:19.640 two cans in a string. Right, You you punch holes 0:13:19.679 --> 0:13:21.439 in the bottom of the cans, You run the string 0:13:21.520 --> 0:13:24.440 through the holes, you stretch it taut, and then you 0:13:24.480 --> 0:13:26.680 can whisper into one can and hear it on the 0:13:26.679 --> 0:13:29.880 other side. But if you whisper that same volume across 0:13:29.920 --> 0:13:33.280 the room you can't hear it. So again that shows 0:13:33.360 --> 0:13:37.400 that the the physical media is actually more or medium 0:13:37.440 --> 0:13:40.240 I should say, is actually more efficient at transferring the 0:13:40.280 --> 0:13:44.320 sound than than air is. So air pockets are actually 0:13:44.360 --> 0:13:49.679 really important when you're soundproofing, you know, designing a soundproof room. UM. 0:13:49.679 --> 0:13:54.480 Typically you would pair decoupling with some of the other elements, 0:13:54.480 --> 0:13:56.080 and I'll go ahead and mention what those elements are, 0:13:56.080 --> 0:13:58.040 and then we'll talk more about how you would put 0:13:58.080 --> 0:14:03.400 it all together. So you've got absorption another important element. 0:14:03.440 --> 0:14:08.199 This is obviously using a material that slows down sound. 0:14:08.600 --> 0:14:11.400 Uh It absorbs some of the sounds, so that sound 0:14:11.480 --> 0:14:15.480 essentially loses some of its energy and it thus is quieter. 0:14:15.640 --> 0:14:18.000 It doesn't it doesn't leak out as much because the 0:14:18.040 --> 0:14:22.440 amplitude gets reduced as a result. Uh. So absorption you 0:14:22.520 --> 0:14:26.920 achieve usually through using some sort of insulation material like UM. 0:14:26.960 --> 0:14:29.880 I mean fiberglass is a simple example where you would 0:14:29.920 --> 0:14:32.120 put that in the wall in the in the gap 0:14:32.160 --> 0:14:34.800 between the two sides of the wall, the two pieces 0:14:34.840 --> 0:14:37.200 of drywall. I saw one even saying denim. You can 0:14:37.280 --> 0:14:40.200 use different like fabric type, interial, cotton or something like. 0:14:40.280 --> 0:14:42.800 The important thing is that whatever you use, you cannot 0:14:42.840 --> 0:14:46.600 pack two densely exactly because if it's too dense, that's 0:14:46.640 --> 0:14:48.720 going to transfer sound and you're back to the same 0:14:48.720 --> 0:14:50.720 problem you were it before. And you also want to 0:14:51.280 --> 0:14:53.440 have still have some air gap there too. You don't 0:14:53.480 --> 0:14:58.200 want the material to make contact completely through the gap. 0:14:58.560 --> 0:15:01.080 You would pack kind of half of the gap, a 0:15:01.120 --> 0:15:04.680 little more than half of the gap. Typically with insulating material, 0:15:04.800 --> 0:15:07.720 you leave an air gap, and that really creates a 0:15:07.760 --> 0:15:12.520 great cushion for sound. UM. We'll talk a little bit 0:15:12.560 --> 0:15:15.520 more about how that can go wrong though. Uh. Decoupling 0:15:15.520 --> 0:15:18.960 in particular can make certain things, um a little more difficult. 0:15:18.960 --> 0:15:23.160 There's also damping sound dampening UH, this is where you 0:15:23.320 --> 0:15:26.920 use some sort of material that resists vibration. So like 0:15:27.000 --> 0:15:29.040 the foam we have here, there's some we've got some 0:15:29.160 --> 0:15:31.440 dampening foam in here. But the typically you look at 0:15:31.440 --> 0:15:34.320 a lot of things like adhesives that are used to 0:15:34.520 --> 0:15:37.360 dampen sound. UM. One of the ones I keep hearing 0:15:37.360 --> 0:15:41.360 about over and over is green glue. Green glue is yeah, 0:15:41.400 --> 0:15:46.040 so so it's very popular, particularly apparently in Canada, but 0:15:46.480 --> 0:15:50.760 it's popular along amongst sound proving technicians. It is considered 0:15:50.800 --> 0:15:53.520 to be one of the most effective for the least 0:15:53.560 --> 0:15:57.680 amount of money solutions for sound dampening material But typically 0:15:58.520 --> 0:16:01.080 this would be a layer that would also be part 0:16:01.160 --> 0:16:05.520 of your wall that resists the vibration of sound and 0:16:05.560 --> 0:16:11.040 so it won't transfer sound as well. Um, it's again, uh, 0:16:11.160 --> 0:16:14.640 something that you would apply between two constrained layers. So 0:16:14.680 --> 0:16:16.680 it's not like it's not like you would cope this 0:16:16.800 --> 0:16:19.480 on the interior wall. That would be a bad idea. 0:16:19.680 --> 0:16:22.560 It would be on the the the back side of 0:16:22.600 --> 0:16:25.360 the interior wall. It might even be something you could 0:16:25.440 --> 0:16:28.960 use as an adhesive for other sound dampening materials like 0:16:29.000 --> 0:16:33.520 acoustic phone or tile. And then the last element is 0:16:33.640 --> 0:16:37.120 really the simplest is mass. It's just that heavier things 0:16:37.160 --> 0:16:40.320 are harder to move than lighter things, right, It's just 0:16:40.400 --> 0:16:42.920 the basic idea like if if you had a cart 0:16:43.520 --> 0:16:47.280 filled with concrete blocks, it would be a little heavy 0:16:47.320 --> 0:16:49.040 to push, But if you had that same cart and 0:16:49.040 --> 0:16:51.200 it was filled with feathers, it's easy to push. So 0:16:51.200 --> 0:16:53.560 I've got something for you. He uses all of those 0:16:53.560 --> 0:16:56.960 elements in a pretty perfect example, one of the more 0:16:56.960 --> 0:16:59.680 perfect examples of soundproofing that we can see in the 0:16:59.720 --> 0:17:02.240 real world. Um, I'm not sure. I think Microsoft has 0:17:02.320 --> 0:17:04.720 maybe outdone them at this point. But there is a 0:17:04.760 --> 0:17:08.840 place in Minneapolis, Minnesota called or Field Laboratories and it 0:17:08.880 --> 0:17:12.439 contains um, what was I believe again until recently, the 0:17:12.480 --> 0:17:16.520 world's most silent room. This world record for the most 0:17:16.560 --> 0:17:21.199 silent room. It is ninety nine point nine nine sound absorbent. 0:17:21.720 --> 0:17:24.959 In order to accomplish this, it uses a combination of 0:17:25.680 --> 0:17:29.360 very very very thick, heavy materials. It's got concrete walls, 0:17:29.920 --> 0:17:33.320 steel reinforcement, and then on the inside of the room, 0:17:33.440 --> 0:17:35.840 I'm looking at a picture right now, it has these 0:17:35.880 --> 0:17:39.840 alternating sort of thin looking things. So you've got like 0:17:40.000 --> 0:17:43.440 three and then going from left to right, and then 0:17:43.480 --> 0:17:46.359 three right next to it, going vertically, and they alternate 0:17:46.440 --> 0:17:50.040 throughout every UM panel in this room, UM, and then 0:17:50.119 --> 0:17:52.400 even on the floor. And the what you stand on 0:17:52.600 --> 0:17:55.280 is a metal grate that goes on top of another 0:17:55.440 --> 0:18:01.199 series of these alternating UM little little units. And apparently, UM, 0:18:01.359 --> 0:18:03.959 the longest anyone has been able to stand being in 0:18:03.960 --> 0:18:06.360 this room alone with the lights out of forty five 0:18:06.400 --> 0:18:10.560 minutes because people start to hallucinate right this level of silence. 0:18:10.640 --> 0:18:12.800 I've I've heard such things and it's the sort of thing. 0:18:12.840 --> 0:18:15.199 Every time I hear it, I have the reaction that 0:18:15.240 --> 0:18:19.040 I think people have, which is bet I could go longer, 0:18:19.920 --> 0:18:21.480 and of course I'd probably be in there for like 0:18:21.720 --> 0:18:24.000 three minutes and be convinced I've been in there for 0:18:24.119 --> 0:18:26.879 three hours. Because once you get to a point where 0:18:27.480 --> 0:18:31.439 something that you have taken for granted, you know just 0:18:31.520 --> 0:18:34.639 the ambient sounds that you can hear once that's gone, 0:18:35.240 --> 0:18:39.159 that really does make a big difference. And uh, it 0:18:39.359 --> 0:18:42.840 is a psychologically powerful experience, but I still kind of 0:18:42.880 --> 0:18:45.840 want to do it. Yeah, that's a great way of 0:18:45.840 --> 0:18:48.600 of kind of summing up all of these elements. Now, 0:18:48.880 --> 0:18:51.320 if you want to really sound proof a room, the 0:18:51.359 --> 0:18:53.840 best thing to do is to incorporate as many of 0:18:53.840 --> 0:18:56.920 those as you possibly can, because they're different. Ones are 0:18:56.920 --> 0:19:00.840 good for different parts of that frequency we're talking about, 0:19:01.359 --> 0:19:03.720 So some of them are really good for those mid 0:19:03.800 --> 0:19:05.920 too high range frequencies. Some of them are a little 0:19:05.960 --> 0:19:08.760 better at the low frequencies. So obviously you want to 0:19:08.800 --> 0:19:11.840 have a good combination. Otherwise you're gonna have certain sounds 0:19:11.960 --> 0:19:15.399 come through even if you've perfectly blocked the room for 0:19:15.480 --> 0:19:18.520 other ones, and that can be really frustrated. Literally, a 0:19:18.560 --> 0:19:21.280 cut off or a threshold where if you looked on 0:19:21.320 --> 0:19:25.240 a graph that can show you what frequencies are happening, 0:19:25.400 --> 0:19:29.800 you could literally track Okay, at this frequency, now I 0:19:29.840 --> 0:19:33.359 can hear it. It's that specific usually, so kind of 0:19:33.359 --> 0:19:37.719 going back to to decoupling a little bit, the size 0:19:37.760 --> 0:19:40.199 of the air cavity between the two sides of the 0:19:40.200 --> 0:19:46.000 the coupled wall determines something called the resonant frequency of that. 0:19:46.440 --> 0:19:49.800 So here's the here's one of the problems with decoupling. 0:19:50.640 --> 0:19:54.320 That air cavity ends up acting kind of like a spring, right, 0:19:54.400 --> 0:19:57.000 So springs actually have a resonant frequency, and if you 0:19:57.160 --> 0:20:00.640 end up vibrating something at the resonant frequency, it causes 0:20:00.760 --> 0:20:04.960 that thing to vibrate very, very easily. The big example 0:20:05.000 --> 0:20:07.720 of this that everyone is familiar with is the crystal 0:20:07.760 --> 0:20:11.560 glass the opera singer hitting that note, that's the resonant 0:20:11.600 --> 0:20:13.600 frequency for it. You can actually see the glass to 0:20:13.640 --> 0:20:17.600 form and ultimately break. Now, or even someone that can 0:20:17.640 --> 0:20:19.560 play those glasses where they fill it up with water 0:20:19.640 --> 0:20:22.399 and run their finger around the rim. In order for 0:20:22.440 --> 0:20:24.600 it to start making that tone, it has to reach 0:20:24.680 --> 0:20:29.359 that resonant frequency exactly. Basically self oscillate exactly. So, So 0:20:29.680 --> 0:20:32.399 here's the problem with the decoupled walls is that that 0:20:32.480 --> 0:20:35.639 air gap, because it's acting like a spring, uh and 0:20:35.720 --> 0:20:39.440 because it can resonate if it's not at the proper 0:20:39.720 --> 0:20:43.439 thickness for the air gap, that resonant frequency maybe within 0:20:43.680 --> 0:20:46.400 the range of sounds that you're going to generate either 0:20:46.440 --> 0:20:49.080 inside or outside the room, within the range of human hearing, 0:20:49.119 --> 0:20:52.240 which means they're going to impact that sound proving it 0:20:52.680 --> 0:20:56.439 if something actually is played at that frequency, it'll go 0:20:56.560 --> 0:20:58.520 not only will it go through the wall, it'll go 0:20:58.560 --> 0:21:01.200 through the wall more easily than it would have if 0:21:01.280 --> 0:21:06.359 you hadn't decoupled the wall because that resonance. Uh So, 0:21:06.640 --> 0:21:08.280 that is one of the things you actually have to 0:21:08.320 --> 0:21:11.280 take into account. And one of the solutions to that 0:21:11.480 --> 0:21:14.879 is don't make it too thin of an air gap. 0:21:15.440 --> 0:21:20.480 Um So, another way of experimenting this with this yourself, 0:21:20.800 --> 0:21:23.840 if you want to just have some fun, and by fun, 0:21:23.920 --> 0:21:27.280 I mean, like you know, Mr Wizard style fun. You 0:21:27.320 --> 0:21:29.680 get a bottle and you know if you blow across 0:21:29.840 --> 0:21:33.640 the the opening of the bottle, it produces a tone. Well, 0:21:33.680 --> 0:21:36.240 it doesn't matter how hard you blow, it's always going 0:21:36.280 --> 0:21:39.280 to play that one tone. But if you add water 0:21:39.359 --> 0:21:42.040 to the bottle, you have decreased the volume of air 0:21:42.359 --> 0:21:44.520 the bottle can hold, and that changes the tone. Again. 0:21:44.600 --> 0:21:47.240 Back to the glasses, they could have, you know, the 0:21:47.320 --> 0:21:50.760 same size glasses, but they generate different tones from each 0:21:50.800 --> 0:21:53.920 one by putting a different amount of water in each. Right, 0:21:53.960 --> 0:21:55.879 it's not just the size of the glass, but how 0:21:55.960 --> 0:21:58.800