What is Surround Sound?

so's he don't get no diseases. That's so pleasant today. Yeah, well, you know, wash your hands, okay, has nothing to do with what we're gonna talk about. No, we're gonna talk about surround the sound. Indeed we are. Actually we're gonna talk about the the effect of surround sounding. Surround sound itself is kind of a I mean, the term came from Dolby, but the concept goes back much further. Yes, indeed it does, so, I mean, it's pretty simple concept.

The idea of surround sound is that you want to create sound in a using recorded sound. You want to be able to play that recorded sound back in a way that sounds like you know, you're in the center of all the stuff that's going on that you know, you've got you've got sounds coming from various directions around you,

so it feels more immersive. Yeah, if you ever been to the movie theater watching a movie where things are you know, someone walks off screen and it you know, you get the idea that they're behind you because you can hear their boots crunching on the gravel from coming from a speaker behind your head, and you go, wow,

that was really cool. That was that was essentially surround sound. Yeah. So, uh, we're mainly going to focus on surround sound um in the home theater environment, not in the movie theater where we are going to do a Movies and Sound podcast. The will be part of our Movie Making Technology series, so don't worry, we will get into that, and the two are related to one another, but we're mainly focusing on like if you want to set up your own home theater and what sort of options do you have?

And you know, what was the progress of surround sound? Yeah, well, of course surround sound actually started in the movies. Sure. The first the first one I could find reference to was fantas Sound, which was created by a couple of Disney engineers for the release of Fantasia UM. But it was it was a very manual process at that point.

Basically they had the track uh playing through different speakers, two different speakers, and what they would do would be to turn one down and the other up uh manually so under direction of somebody, so that it appeared to to have the effect of moving across one another. Because originally we're talking about monophonic sound mono meaning one, so you have one sound source and all the sound is

coming from that source. Now you could have multiple speakers hooked up to a monophonic system and it would just be that that same sound, the same the exact same sound would be coming from each speaker at the same intensity. UH. So you know, you could make yourself feel like you were in the center of sound by putting a series of monophonic sterry speakers around you, but there'll be no

differentiation there. It wouldn't be like you could hear the violins off on one side while the cellos are are behind them and and the brass section is to the other side. You wouldn't be able to get that differentiation. It would be the sound of the entire orchestra being all around you everywhere. M Yeah, Actually I misspoke because the article that I had found in the Journal of Society of Motion Picture Engineers by William E. Garritty and Janny Hawkins, so that there was a center channel and

two speakers, one on either side of the center. So what they would do would be to change the U turn one up and the other down on the side speakers. The center speaker would would continuously play the monophonic sound right for that, but I straight manually fading it in and out. And that's not terribly terribly different from what goes on now, but it's so much more sophisticated, right, right,

So after monophonic sound, we could talk quickly about stereophonic sounds. Yeah, that's the concept where you divide the sound up into multiple channels and then you direct the the channels to specific speakers. Um. And we generally think of this as uh as as being a two speaker system, but technically stereophonic can refer to more than just two. It's just that you know, in the common vernacular, when you say stereo, you think of two speakers, so generally a left and

right speaker. This is the kind of sound system that works really well with headphones, so that you record certain sounds on the left channel or in certain sounds of the right channel, or you mix them so that certain sounds only kind of come across on the left or

the right um. And by doing that you can give the sort of the illusion that you are in the middle of whatever it is it's making the sound that The example everyone always uses is orchestras because I mean, you think about it that it's it's easy enough to say, all right, well, this would be like if you were standing directly in front of the orchestra, because if you were there, you would be able to hear that the you know, all the music is coming from the orchestra

in front of you, but different parts of the orchestra are generating that sound at different times, so you would hear like the violence would sound like they were off to one side, and the brass would sound like it's on the other side. UM. So, the the goal of stereo was to try and recreate that sensation as accurately as possible when you're playing it back yourself. And it's

a pretty simple and a pretty simple concept. Right You're sending one set signals to the left speaker, and one says signals to the right speaker, and both maybe playing some sounds at the same time, but they'll also be playing sounds that are unique to that particular speaker. That's true. Surround sound GET does that and makes it way more complicated. Yeah, I think I think I would throw in my my my pet research project here, Okay, Yeah, because it's a

good bridging. Yeah, I was thinking about the areas we were sort of what I was mulling over. UM. One of the things I told Jonathan I wanted to talk about was quadraphonic sound UM, which I had always heard about UM growing up in the seventies and eighties, but never really had the opportunity to experience. And it's very hard to experience now, But it was just because people

don't use it really anymore. But guadrophonic sound, if you've ever heard of it, it is as you would expect with the prefix quad uh four channel version UM with left front, right front, left rear, and right rear speakers UM. And this it was sort of an early seventies project. A lot of the the high fidelity type audio manufacturers

came out with equipment that would support it. UM you would see eight track tapes, vinyl records and real to real audio tape with you know recordings and in quadraphonic format. UM and it pretty much works very in very very similar ways to UH to stereo sound. The problem I think probably was judging from my research, is that it required special equipment. The eight tracks that had it were formatted differently. UM. They had only one side with fewer

programs rather than two sides. UM and uh. You know, to to play a vinyl record, you had to have a special stylist because the grooves were cut a little differently to support the different channels. Since you have four discrete channels of audio going to four different you know,

each channel is going to a different speaker. UM. The of course, here, the idea is that the listener would be in the center of this the square that's made by the four speakers, and that through managing the levels of each speaker and the types of sound that are coming through speaker, you could create you know, a sound scape if you want to. You know that that's a pretty common term term soundscaping, where you're trying to create a particular experience through sound to make it very immersive.

And uh and and you know, audiophiles are always looking for the really immersive and really um um well true to life, yeah, playback option because you want you want to sound at least if you're an audio file, you want to sound as close to as if you were actually there when the sound was being generated as possible. Yeah. The uh, the system also required a special demodulator to um, especially if you were going to play both stereophonic, well monophonic,

stereophonic and quadrophonic records on the same system. Um. You know, it really was kind of equipment intensive. Um. And then there was another format of quadrophonic sound, Compact Discrete four or c D four not to be confused at all, the compact disc format UM, and it you know, it was one of those things where it was a format war. JVC was was behind this, and they apparently a lot of people really liked it, uh or really really hated it,

depending on whom you ask. UM. But they were incompatible formats, and I think the cost of the equipment and the mess with all the different formats kind of you know, caused the whole quadraphonic thing to fade away. And then of course we got into uh as we moved into the nineties, we got into CDs, and you know, people weren't making CDs to to work with quadrophonic sound anymore,

so it just disappeared. Yeah. Um, I mean audiophiles will probably still cry out and say, hey, I still have my quadraphonic system and it's awesome, because they're very proud of them. I mean they do. There are a lot of people who still have them out there, But you have to find the equipment that actually still works. Is the problem, because no one's manufacturing it, right, the equipment and the the you know, the stuff to play on it. Um,

and someone is manufacturing it, they're probably a very small manufacturer, right. So, so true quadrophonic sound is you have four audio channels and you have four speakers, and so you've got it's it's four it's called four four four because it's it's it stays four discrete channels through the whole um, the whole process. You can also achieve quadrophonic sound, and some quadraphonic systems were able to do this by getting four

lines of information out of two lines of information. This gets really kind of a kind of confusing, but that's called like the four to four processing system. Right, So you start off with four different UM channels. You can press that down into two lines of information, and then you have a decoder that brings it back up to four. And uh, I'll see if I can explain this in a way that makes sense. It's hard to do when

you don't have a visual to go with it. So maybe maybe at some point UM UH will do some sort of video where we'll talk about this. But if you do find this confusing, we have some great articles on the site on both how movie sound works and how surround sound works where you can kind of see what I'm talking about. So with a four two four system you have for the four different kinds of information information are the the sounds that are unique to your left speaker. This is again in a in like a

a regular surround sound system. You have the information that is only going to the right speaker, you have the information that's going to both, and then you have the information that's only going to the surround speaker. So this would normally be a speaker that's to your left, a speaker to this's your right, and the speaker that's behind you, okay, um. And the way that they get the the last two to work. Uh. It all depends on whether or not the signals are in phase or out of phase with

each other. So left and right is easy right, because you're just sending the information to one speaker or the other speaker. Sending it to both is also easy. You send both both speakers the same information or both sides the same information at the same time. So if you were to look at the waves like the sound waves, they would match up perfectly. It'd be the same amplitude

and same frequency. To do the surround sound. What they do is too so that you don't get the sound from the front speakers, the ones that are in front of you, and you want to just get the ones that are around you. Uh, you put them out of phase. And by saying out of phase that what that means is that when you have the peak of the sound wave from one speaker, it matches the trough of the sound wave of the other speaker, so it's opposite exactly,

it's opposite. So while one is speaking, the other one is a trough. And this is important. This this relates to how the speaker itself moves. There's a speaker cone in your speaker that vibrates. That vibration is what generates the sound you hear, which is also kind of amazing.

We'll have to do a podcast just about speakers at one point to talk about how a little vibrating speaker cone can generate all the different sounds you hear when you listen to any prerecorded stuff, or actually any broadcast stuff, anything that's coming over a speaker. I mean, it's it's this little vibrating film that's generating that sound. So anyway, the when it's out of phase like that, the two sound waves cancel each other out, so we don't really

perceive them. Yeah, that's sort of, in a way, a little bit like how noise canceling headphones work. Yes, exactly, it's exactly the way noise canceling headphones work. In the sense that you want to be able to create a wave that matches but is out of phase with the the one that you're trying to dampen, right, and so you get the dampened the dampened speakers, you don't hear the sound from. You do hear the sound from the

surround sound speakers. Um, And all it takes is encoding the these lines of information the right way so that the waves match up or don't match up. And then when it's played back through whatever system you're using, usually like a DVD system or whatever, UM, there's a decoder that takes those two lines of information and then decodes that into the four the four different streams UM. So that that's kind of that was kind of the next step. And like I said, some of the quadriphonic systems were

able to do that. They weren't just the four four four discrete systems UM those great little phase shifts. I find that really fascinating. It also meant that if you had a left speaker and a right speaker and they were playing the right frequencies, you would get an effect as if there were a speaker directly in front of you, and that that we call that the phantom speaker because

there's not a physical device that's generating that sound. It's just because the way that the other two stereo speakers are are generating sound at the same time, it gives you the effect that there is a speaker there. Okay, we'll see that. That makes so much more sense now because I thought it was a speaker that could punch you so hard that it would leave an impression of its bringing your face. See, I thought it was a speaker that was supposed to be developed to play all

these different video games, but never actually came out. We're just making phantom jokes now, and someone's going to complain because those are inside jokes, not even inside jokes, really, folks, that's just reference. That's simon and inside joke. We're just making very obscure references. Uh. So that that four too, four is an example of a matrix system. The matrix are the systems where the processing systems where you you you combine various lines of of channels into one or

two or however many discrete. Um. Uh, Well, I guess discreet would be the wrong word, because discreet would mean that you would have one per one channel, person per speaker. But it's when you combine these this lines of information that will later be decoded to become UMU to go to each individual speaker so that you get that surround sound effect. Um. Did you want to talk about the differences between things like five point one, six point one,

seven point one, etcetera. Well, yeah, that's uh, that's essentially the number of speakers, or actually the number of channels that you have. The first number is the number of regular channels. In the second is the number of I guess base, yeah, lf E low frequency UM channels. That's what's going to your subwoffer. Yeah. Yeah, And it sort of reminds me of what a friend of mine used to call the earthquake speaker. I used to uh used to go to a club that had one of the

you couldn't even tell it was on. It was this giant cube. It was one of the speakers that it was created for the movie Earthquake in the seventies, and its job was not to make a sound that you could hear. It was. Its job was to make a sound that you could feel that made it feel the floor feel like it was shaking, but you couldn't hear anything coming out of it. Was just that the base was that low, right, it was beyond beyond the range

of human hearing exactly. Yes, we can definitely sense it through uh, Like like you said, you could feel it, yeah, and yeah, it's the same sort of thing that when you go see a movie where there's a big explosion and you feel you're feeling your chair rumbled. That's that's what that is. So that's yeah, the five, the five

point the h and that speaker. The speakers in and home theater systems are not nearly as uh you know, powerful as those used for the movie theaters and your average home theater system last year, because there are there are a few crazy people out there who have some really powerful speaker systems and a whole lot of money to blow on that, because we're talking like, you know, the tens of thousands of dollars for for these kind of speakers, but the kind that you would pick up

at your local electronics store for most people is uh probably these days, I would I would guess at five point one or seven point one, in which case you've got um, the center speaker. Uh. In the case at five point one, two in the front and two on the side, or you know, just behind you. Um, the seven speaker set up is a little more diverse. You've got a couple behind you and maybe even I guess a real real channel. There's a six point one too.

Well it's a single one behind you and then the other one has the two So yeah, it's it's just basically dividing the number of channels up and the more the more channels you've got the more speakers you've got, so you you placed them strategically around you to create that that sound, and you just took up the channels indicated. And the strategically part is very important because the sound has been designed for specific for it to come from

a specific direction exactly. In other words, with five point one, you couldn't just you know, put the five speakers around you in any orientation. Yeah, you have to put them in a certain place if you want to achieve the desired effect. I suppose you could put them in in just random places and it would be kind of weird, but yeah, it wouldn't don't match up to anything you were watching or now if you're just listening to music, it might not make as big a difference. It just

wouldn't give you the effect that was intended. Now, so five point one, Yeah, you've got that. You've got your center channel. So that's that's usually in the movies, the center channel is where most of the dialogue comes from. That's because it appears to be coming from the screen, right right. Yeah, It's one of those things where we just we've kind of trained ourselves that if we're looking at a person and they're talking. Uh, the sounds should

pretty much come from that direction. Um. It's only if a character is off screen and talking that we normally would hear that person speaking through one of the other speakers, uh, the other. So that you've got that's number one is your center channel. Then you've got your front left in your front right, which are usually set you know obviously off to the side, to the left and right of the center channel. UM. Then you have your rear left and your rear right audio and those would be behind

the viewer or listener. So that's the five. You know, you've got one five, the three in the front and two in the rear. Then you've got the point one would be the sub Wliffer six point one. Usually, UM, it depends because there's no set standard for surround sound.

There are many companies that have come up with different surround sound UM approaches, but in general a six point one surround sound set up there's usually an additional rear center speaker and that's normally used specifically for sound effects. So it's not you know, that's to give you that more rich immersive experience, but it never it didn't really take off. Six point one just was one of those things where you know it just it was it was almost people begin to view it, I guess as we

would get this just because we can. And it never really took off, at least in the home market. Seven point one does rearrange the orientation a little bit. Uh, So you've got instead of the additional rear speaker, Um, you've got additional speaker to your left and one to your right. So you've got you've got the three in front of you. You've got one tier left, one tier right like immediately to your left and right, and then the two behind you. And so that's that's all seven

right there. Uh and then right now is pretty much the top of the home theater system. But it's not people of course are not stopping there. Why would they. But but yeah, that that's usually what you would see in your local electronics store five five point one in seven point one systems, Yeah, you might see some six point ones too, but like I said, they didn't really

take off very much. So usually you see, you know, the five point one being the more um popular is probably the wrong word, but just that's the one you're going to find the most often. I think seven point one you'll find when you're looking at some of the higher end sound systems. I'm sure there's some that are in the more approachable like low end market by now, but um, I haven't been in the market for home theater system in a long time, so I don't I

wouldn't really know. But I wanted to talk just briefly about another experimental system which was developed by Tomlinson Holman of t H Labs and uh really I wonder how they got their name. Yeah, uh, yeah, he was. He was a guy who was behind the the th h X quality assurance standards. UM. So yeah, th h X. If you if you're familiar with th X sound, that's

not actually a a sound recording or uh playback method. Really, it's a set of standards that um that any sort of system is supposed to meet in order to It's almost like a certification like if you if you meet certain requirements, then you can be th X certified. But he developed ten point to surround sound. Yeah, so ten point two. First of all, you got the point to which tells you that you have two sub wiffers. Do

they go in different places? Yes, you have one on the left and one on the right, which is pretty odd because usually most most surround sound system designers will tell you it doesn't really matter where you put the subwiffer because again, you're not hearing it, you're feeling it.

So as long as as long as your subwoffer has sufficient power and the room it's in is not you know, the wrong size, like you don't want a little subwiffer in a huge room, right, Um, as long as as long as it's a big enough subwoffer and it's getting enough power, it shouldn't matter where you put it because you should still feel the effect. We're not quite so sensitive that we can detect the origin of that rumbling that we're feeling as we're watching. You know, Bruce Willis

run away from an explosion. But the ten point two has two subworiffers, one on the left, one the right. So the idea being that if you do tune it just right, you should be able to experience that rumbling as it passes through the theater. So let's say you're watching a movie like Twister and there's a tornado that's moving from the left side of the screen to the

right side of the screen. If you timed it just right, you might be able to give you that feeling that hey, there's something really huge coming from the left and now it's moved over there to the right. UM. I don't know. I've never experienced this particular system, so I can't tell you how effective it is. Uh. But then let's see they've got you've got your three speakers in the front, so you've got your center, your left center, in your right center. Then you have UM a left and right speaker.

Then you've got three additional UM left and right speakers, so these are the ones that are going going around the back of you right, and then you have an upper left and upper right speaker give your sense of height. So that makes Yeah, the goal here is to give you because we've got it. We've we've developed surround sounds so that we get up pretty much a kind of a one and eighty degree sound environment right where where we could theoretically have in a really good surround sound system.

Have a character as if this character we're walking around us in a circle, like we're staying stationary in the center, and this character walks around us and delivers a speech, it would sound as if this arter is actually walking around us right right, because they're feeding the audio through the different channels, right, and they're fading it out and bringing it up at just the right moment to create

this illusion, this audio illusion. Well, the ten point two is the goal is to create a three hundred and sixty degree soundscape around you. So now the character could go overhead and continue talking and it would sound to you as if the person was not only going around you, but was going over on top of you. So Superman, for example, could do a little slow fly over and speak to you and it would sound like he's going

directly overhead. Um, that's the goal. Again. I don't know how successful it was, because I my invitation must have been lost. I didn't get to go to this, uh, this experiment. You know, it would be interesting to see what what kind of stuff they do have at CEES related to surround sound, you know, and I've sat through some surround sound demonstrations at c e S. But in in general, the CS stuff is really just another example

of the technology we're already familiar with. It's just them fine tuning it, making the speakers more powerful, trying to create sounds more accurately so that there there's a better precision to playing back sound. UM, it's not really developing the three dimensional aspect as much as it is you know, making sure you're reproducing sound as accurately as possible. But that's the general concept behind surround sound. I mean really, like we said, when you get down to it, the

idea behind it is pretty simple. You just want to create the right kind of sounds that the right kind of location to give you that immersive experience. But when you actually get around to trying to develop the technology to do it, uh, it gets really complicated. And even though we've talked about five point one six point one, seven point one tin point to all this stuff, as we said at the beginning, there are multiple ways of achieving this. UM. The way that Dolby does it is

different from the way it's Sony does it. UM. They all have the same goal and they all essentially use the same sort of speakers, but they use different encoding methods and decoding methods. Which is why if you are shopping for say a DVD player, some DVD players will tell you that they can play uh, Dolby Digital, but they can't. You know, they may not have anything on there about other surround sound methods. Most of them have support from multiple surround sound uh technologies, which is good

because different companies use different surround sound vendors. So you know, you could buy two different DVDs and one of them sounds amazing on your system and the other one just sounds like regular mono to you almost or stereo um

really Uh. It's important to to look at the the model of whatever technology it is you're buying, whether it's a stereo system or theater in a box or a DVD player, the decoder is the most important part of that um of that system as far as surround sounds is concerned, because you could have as many speakers as you want, but if you don't have the right decoder, you're not going to get that surround sound effect right because otherwise, you know, it's basically running traffic. Yeah, you know,

to the different to the different channels. Yeah, it has to. It has to be able to identify what sound goes where and when. Um, which you know, again, we we tend to to imbue our technology with a little artificial intelligence, which is misleading, but you know it's it's just slightly better than me saying it's magic, which I've always tempted to do when I sit down here, just because it would make these podcasts go a lot faster and I can get back to other stuff. Elves. Elves make it work. Yes,

So anyway, that wraps up surround Sound. If you guys have any comments or questions or you have suggestions for other topics, like I that we will be doing a movie sound and podcast in the future to kind of be a partner with this one as well as part of our movie making technology podcast. We'll even probably go into more detail about the house around sound came about in movie theaters and probably talk about Fantasia specifically. Um so keep an ear out for that, huh, And did

you have something else said? No, I was gonna say we probably, I would imagine get into a little bit more about Delby and DTS and all that stuff into yeah, yeah, because that's really applies a lot more right. It all started in the movies and then migrated to home theater. So if you guys are disappointed that we didn't go into more detail about Delbi or DTS, we're really looking

at doing that for the movie sound. Actually, the movie Sound may end up being two podcasts just because we'd have to talk about how they get the sound to match up with the movie, as well as the various surround sound methods. But that's good. It just means that we have fewer topics that we have to brainstorm. Yes, just did we end up to saying which one when we're going to get around to them? By the way, the way we do that is through growing darts? Probably guessed,

but it's true. And we will talk to you again really soon. If you're a tech stuff and be sure to check us out on Twitter tech Stuff hs wsr handle, and you can also find us on Facebook at Facebook dot com slash tech Stuff h s W. For more on this and thousands of other topics, visit how stuff Works dot com and be sure to check out the new tech stuff blog now on the House Stuff Works homepage, brought to you by the reinvented two thousand twelve camera. It's ready, are you