Speaker 1: Get in text with technology with tech Stuff from how
Speaker 1: stuff Works dot com. Hey there, and welcome to tech Stuff.
Speaker 1: I'm your host, Jonathan Strickland. I'm an executive producer at
Speaker 1: how Stuff Works and all of all Things Tech, and
Speaker 1: today we're going to talk about a subject that was
Speaker 1: another listener request, and I actually talked about this briefly
Speaker 1: in the Listener grab Bag episode. Listener MICHAELA had asked
Speaker 1: me to talk about speakers and headphones, how they work
Speaker 1: and where they came from. And today we're gonna cover speakers.
Speaker 1: I was gonna cover both in one episode. That turns
Speaker 1: out there's just too much to talk about if I
Speaker 1: really want to explain where these things came from and
Speaker 1: how they evolved over time. They are very closely related,
Speaker 1: but I feel like I'm gonna have to save headphones
Speaker 1: for a future episode. Uh So, this ties in really
Speaker 1: closely with some of the other recent episodes I've done
Speaker 1: about tech and music, like Middy and turntables. In fact,
Speaker 1: the turntables and record player stuff. The speaker development goes
Speaker 1: hand in hand with that because it was all part
Speaker 1: of the development of the recording industry as a whole. Well,
Speaker 1: a quick reminder we're talking about sound, and I promise
Speaker 1: i'll make this brief. Sound travels through a medium. It
Speaker 1: can be any sort of medium. Really can be solid,
Speaker 1: it can be liquid, it could be gas. Sound is vibration,
Speaker 1: So molecules or atoms within this medium are going to
Speaker 1: bounce against each other and propagate sound throughout that medium,
Speaker 1: So you have to have molecules there. This, by the way,
Speaker 1: is why sound does not travel in outer space, because
Speaker 1: while outer space is not totally empty, there are particles
Speaker 1: in outer space, they're so far apart from each other
Speaker 1: that you can't have them bump against each other and
Speaker 1: propagate sound. So that's why there's no sound in space anyway. Uh,
Speaker 1: we experience sound when vibrating air molecules change the air
Speaker 1: pressure in our air canals. At least this is the
Speaker 1: primary way we experienced sound. And when that happens, the
Speaker 1: air pressure means that it either presses against our ear
Speaker 1: drums also known as the tympanic membrane, or the pressure
Speaker 1: is reduced so that our tympanic membrane presses out because
Speaker 1: there's there's not as much pressure as there normally would be.
Speaker 1: As these vibrations that then gets sent through a series
Speaker 1: of tiny bones that then send vibrations to a structure
Speaker 1: called the cochlea in our inner ears that wiggles around
Speaker 1: some fluid which then wiggles around some special nerve cells
Speaker 1: which send electrical impulses to our brain that we then
Speaker 1: interpret as sound. And I know I've said that a
Speaker 1: couple of times in recent episodes, but it always bears repeating,
Speaker 1: because we have to remember, ultimately, sound is this physical phenomenon.
Speaker 1: It's not just some magic stuff that floats through the air.
Speaker 1: It's actual physical vibrations, and it's in warn't to know
Speaker 1: that because as we got a greater understanding of the
Speaker 1: nature of sound, we were also building on our understanding
Speaker 1: of physics, of electrical engineering, of lots of stuff that
Speaker 1: all together made it possible for us to make speakers. Now,
Speaker 1: before electric loud speakers, we mainly relied on just acoustics,
Speaker 1: the physics of sound, and for a while we didn't
Speaker 1: necessarily have very detailed mathematics to describe the acoustics of sound,
Speaker 1: which by the way, are incredibly complicated. I could do
Speaker 1: a series of episodes about the acoustics of sound, and
Speaker 1: it would take a really long time to do so.
Speaker 1: I'm only going to touch upon acoustics in this, but
Speaker 1: acoustics involve everything from the design of say a room,
Speaker 1: like have you ever been in a room that was
Speaker 1: designed acoustically for the performance of music? You've probably experienced
Speaker 1: some really nice performances that way. But there's also acoustic
Speaker 1: design in things like instruments, including horns, and horns would
Speaker 1: largely represent the way we would try to amplify sound
Speaker 1: before the electric loudspeaker like the megaphone is a classic example.
Speaker 1: So how can a simple shape make a sound louder? Well? Again,
Speaker 1: to dive into all the details would be an episode
Speaker 1: by itself. Plus I would kind of need visual aids
Speaker 1: to really explain it properly because doing this all just
Speaker 1: an audio format is very challenging. But in general, when
Speaker 1: you have a horn or a tapered tube where it
Speaker 1: tapers down to a narrow end and then you've got
Speaker 1: a wide end on the other side, you can send
Speaker 1: sound waves down the length of this tube as plane
Speaker 1: waves p L A n E. Those are waves that
Speaker 1: travel in parallel with one another. So you have one
Speaker 1: wave behind that, you have another wave in parallel behind that,
Speaker 1: you have another wave in parallel and so on. It's
Speaker 1: kind of like a stack of waves. Now, the tube
Speaker 1: needs to be narrow at one end to fit the
Speaker 1: source of the sound, such as your mouth or with
Speaker 1: acoustic speakers. Back in the old days when you had
Speaker 1: the gramophones, you know those big trumpet looking things that
Speaker 1: stuck out of what looked like a record player. Well
Speaker 1: that had to be right around whatever the membrane was
Speaker 1: or the speaker driver in order to help amplify sound.
Speaker 1: The tube then has to flare out because if it
Speaker 1: remains narrow, sound waves would start to reflect off the
Speaker 1: sides and that would that would start to affect the
Speaker 1: loudness as it went down the path. And that's largely
Speaker 1: because of wave size. Lower frequency sound waves have longer
Speaker 1: wave forms, so you need to flare out the horn
Speaker 1: to allow for those longer frequencies. And this is why
Speaker 1: instruments like the tube but have such a large flared
Speaker 1: horn at the end because they're playing those lower frequency sounds,
Speaker 1: whereas something like a trumpet can have a smaller flare
Speaker 1: because they are not playing notes that are at that
Speaker 1: low of a frequency. The design of a horn transforms
Speaker 1: sound waves by taking the high pressure, low velocity waves
Speaker 1: emitted into the narrow end also known as the throat
Speaker 1: of a horn, and then converts those into low pressure,
Speaker 1: high velocity vibrations at the wide end, so high pressure
Speaker 1: low velocity to low pressure high velocity, and the high
Speaker 1: velocity vibrations can move through the air more efficiently. In addition,
Speaker 1: a horn restricts the spreading out of sound waves. It's directional.
Speaker 1: Sound will emanate out in all directions from a source normally,
Speaker 1: but with a horn you can restrict that a bit.
Speaker 1: You direct the sound a little bit toward an intended
Speaker 1: target and thus deliver a more concentrated collection of sound
Speaker 1: waves at that target. But while horn acoustics are pretty
Speaker 1: amazing and fascinating, they are not the ideal solution for
Speaker 1: amplifying sound in all situations, which brings us to the
Speaker 1: invention of the electric loudspeaker. Also, I should mention that
Speaker 1: electric loudspeakers frequently make use of the principles of horn
Speaker 1: acoustics in their design. So just to get that out
Speaker 1: of the way, it's not like horn acoustics no longer
Speaker 1: or apply. It's just we're not relying solely on horn
Speaker 1: acoustics for amplification. At this point. The first electric loudspeaker
Speaker 1: was part of an invention called the telephone. Now we
Speaker 1: all know Alexander Graham Bell gets the credit for inventing
Speaker 1: the telephone, but it was actually another person, a German teacher,
Speaker 1: Johan Philip Rice, who was actually the original inventor of
Speaker 1: a device called the telephone. He called his device a telephone.
Speaker 1: It was different from the telephone that Alexander Graham Bell
Speaker 1: would invent, but it was a device. It was called
Speaker 1: the telephone, and it came out about two decades before
Speaker 1: Alexander Graham Bell got into it. Uh so it's not
Speaker 1: nearly as transformative as Alexander Graham Bell's invention in eighteen
Speaker 1: sixty So okay, more like fifteen years before Graham Bell's breakthrough,
Speaker 1: Rice was hard at work creating an electrically powered device
Speaker 1: meant to mimic the human ear. In fact, his early
Speaker 1: early versions of this look like a human ear carved
Speaker 1: out of oak, and even had these little metal parts
Speaker 1: that were supposed to replicate the way the bones in
Speaker 1: our ear drums work or behind our ear drums work. Well,
Speaker 1: he thought he could transmit sound through electric wires, harnessing
Speaker 1: something called magnet restriction Now, this is a phenomenon in
Speaker 1: which a feral magnetic material like iron will change in
Speaker 1: dimensions due to a change in the magnitude and direction
Speaker 1: of its magnetization. So essentially what this means is if
Speaker 1: you get something that's feral magnetic, like an iron bar,
Speaker 1: and you put it inside a magnetic field, and it's
Speaker 1: a weak magnetic field the h and you put it
Speaker 1: in such a way so that the direction of the rod,
Speaker 1: as in the length of the rod, match the magnetic
Speaker 1: fields direction. The rod would actually get a little bit
Speaker 1: longer through this weak magnetic field. Now, if it were
Speaker 1: a strong magnetic field, the rod would actually contry tracked
Speaker 1: a little bit, would be a little shorter than normal.
Speaker 1: And if you had a very precise way of measuring
Speaker 1: the rod, you could actually see that the length of
Speaker 1: the rod changed as the magnetic field changed. So if
Speaker 1: you change the field strength, you could actually dynamically change
Speaker 1: the length of the rod by a very small amount.
Speaker 1: And moreover, doing this would cause the iron rod to
Speaker 1: create a tick sound. Passing a variable current through a
Speaker 1: coil of wire could cause the rod to tick repeatedly,
Speaker 1: generating a sort of tone, and that became the receiver
Speaker 1: of Rice's invention, it became his speaker. This ticking iron
Speaker 1: bar was essentially a speaker. Rice created a device that
Speaker 1: acted as a transmitter. The ear had a parchment membrane
Speaker 1: inside of it that mimic the tympanic membrane in our ears.
Speaker 1: Against that membrane was a little metal strip, So he
Speaker 1: had essentially glued like a platinum strip to this membrane,
Speaker 1: and resting a against that platinum strip was a second
Speaker 1: strip of platinum which was just barely touching the membrane
Speaker 1: due to gravity. So they were just making gentle contact
Speaker 1: with each other. In fact, we would have called this
Speaker 1: a loose contact if it had been done on purpose
Speaker 1: for an electrical circuit, and when the circuit was powered,
Speaker 1: when electricity was flying going through it, uh, it would
Speaker 1: actually everything's working fine. The two contacts are in in
Speaker 1: connection with one another. Uh, you would be able to
Speaker 1: have pass electricity through without any issues. But Rice believed
Speaker 1: that if you made sounds into this simulacrum of an ear,
Speaker 1: you could make the membrane vibrate, and he believed this
Speaker 1: would cause the metal contacts to bounce against each other
Speaker 1: and cause the current passing through the circuit to become intermittent,
Speaker 1: and this would be what he would call and what
Speaker 1: others would call a make or break transmission. So if
Speaker 1: you think about something like a telegraph, where when you
Speaker 1: press down on the key, it completes a circuit, and
Speaker 1: when you let off of the key, it breaks the circuit.
Speaker 1: He was thinking along those same lines, except he was
Speaker 1: thinking this would be a way for you to transmit
Speaker 1: actual sounds, not just uh, the the signal that there
Speaker 1: is an electric circuit made and broken. That's what he
Speaker 1: thought was behind this whole idea, and so he started
Speaker 1: to experiment with this, and he thought eventually he could
Speaker 1: do he could create a system this way where you
Speaker 1: could transmit sound through electricity. You would put the sound
Speaker 1: into the transmitter, it would do this make or break
Speaker 1: series of connections, and then on the other side you
Speaker 1: would have this iron bar that would start ticking, and
Speaker 1: the ticking would be done in such a way that
Speaker 1: you would be able to make out what was the
Speaker 1: original sound put into the transmitter. Side now in a courtroom,
Speaker 1: because eventually his design would be brought into court proceedings.
Speaker 1: When Alexander Graham Bell came forward with his invention of
Speaker 1: a telephone, well, we'll find out what happened in the courtroom,
Speaker 1: but first let's take a quick break to thank our sponsor.
Speaker 1: Scientists testified that the only way this even worked at
Speaker 1: all was if the sound was not too loud, and
Speaker 1: so the two strips of metal would never lose contact
Speaker 1: with each other. They would press more gently against each other,
Speaker 1: but they would still remain in contact, and that this
Speaker 1: would end up varying the electrical resistance of the circuit,
Speaker 1: which would change make it a variable current flowing through
Speaker 1: the circuit, and that is what made the signal that
Speaker 1: made it possible for you to hear something on the
Speaker 1: other side. So not that there was a make or
Speaker 1: break connection, but rather that the connection that was made
Speaker 1: had a variable resistance and thus a variable current, and
Speaker 1: that is what drove the receiver on the other side.
Speaker 1: The reason this is important as they were saying, yeah,
Speaker 1: technically Rice's inventions sort of works, although it wasn't producing
Speaker 1: clear representations of the original sound. You could tell that
Speaker 1: it was making a sound based upon the original one,
Speaker 1: but it wasn't clear. You couldn't get intelligible speech out
Speaker 1: of it. They said, yes, it is working, but it's
Speaker 1: not working the way he thought it was the way
Speaker 1: he described it. It can't work that way, because that's
Speaker 1: not the way that that's not what we're seeing. What
Speaker 1: we're seeing is the only way it works is that
Speaker 1: the sounds are quiet enough to not break the connection,
Speaker 1: but only change the electrical resistance of the circuit. So
Speaker 1: while his his invention works, it doesn't work the way
Speaker 1: he wanted it to. So his patent is invalid, and
Speaker 1: the courts upheld this. And some people find this really
Speaker 1: interesting that you could have something that technically works, but
Speaker 1: if you describe how it works and you get the
Speaker 1: description wrong, that is what ends up being important, not
Speaker 1: whether or not your invention actually does anything. Uh. And
Speaker 1: that in fact was the case. And Rice got really
Speaker 1: kind of disgusted by all this and kind of got
Speaker 1: out of that area of study. After the Brewjaja over
Speaker 1: Alexander Graham Bell's invention. Speaking of Alexander Graham Bell, we
Speaker 1: should chat about his version of the telephone. He patented
Speaker 1: his first electric loudspeaker as part of his telephone invention
Speaker 1: in eighteen seventy six. Now, later on he did acknowledge
Speaker 1: Rice's work as part of the inspiration for his own invention,
Speaker 1: but Graham Bell avoided the problems Rice encountered. Alexander Graham
Speaker 1: Bell was in a race to patent his invention before
Speaker 1: a rival of his named Elisha Gray could get his
Speaker 1: own implementation patented. So he had Elisha and you had
Speaker 1: Alexander Graham Bell, and they were both working on this furiously,
Speaker 1: and in fact they both filed for patents on the
Speaker 1: exact same day. There are people to this day who
Speaker 1: argue that Elisha Gray should get the credit for inventing
Speaker 1: the telephone rather than Alexander Graham Bell. Now, their inventions
Speaker 1: were similar but distinct. They were not exactly the same thing,
Speaker 1: so it wasn't necessarily that one was copying the other,
Speaker 1: although there have been allegations that perhaps Alexander Graham Bell
Speaker 1: had a look at Elisha Gray's um design and then
Speaker 1: based some changes in his own design on that. Whether
Speaker 1: those allegations holding the merit, I'll leave to other people.
Speaker 1: It gets real ugly if you want to read into this.
Speaker 1: But the two had been in competition for years. They
Speaker 1: had been working against each other in the field of
Speaker 1: telegraphy well before they started getting into the idea of
Speaker 1: a telephone. And I'm not gonna go any further into that,
Speaker 1: just to say, if you want to look up some
Speaker 1: pretty interesting muck raking, look at Alexander Graham Bell and
Speaker 1: Elisha gray Well. Alexander Graham Bell mounted a piece of
Speaker 1: magnetized iron to a membrane, or rather he told his
Speaker 1: assistant Watson to do this, and an electro magnet would
Speaker 1: attract or repel this magnetized iron as it received the
Speaker 1: incoming variable electric current from the transmitter. The membrane was
Speaker 1: able to reproduce sound, but at a low volume, So
Speaker 1: in other words, he would speak into a transmitter. The
Speaker 1: transmitter had a membrane in it that would, through its
Speaker 1: vibrations very an electric current. That electric current would travel
Speaker 1: through a wire to the receiver. And on the receiver
Speaker 1: side you had another membrane on which was a piece
Speaker 1: of uh magnetized iron, and you had an electro magnet
Speaker 1: just below it that would receive this variable electric current
Speaker 1: and thus attract and repel the iron that was on
Speaker 1: this membrane, making the brain vibrate. That's what ended up
Speaker 1: replicating the sound. In eighteen seventy four, another inventor named
Speaker 1: Ernst Siemens, the co founder of the Siemens Company, made
Speaker 1: an important contribution to the development of the modern speaker.
Speaker 1: He received a patent for his description of an electro
Speaker 1: mechanical dynamic transducer which used a coil of wire suspended
Speaker 1: in a frame so that it could move axially and
Speaker 1: only axially. So his patent described a magneto electric apparatus
Speaker 1: for obtaining the mechanical movement of an electrical coil from
Speaker 1: electrical currents transmitted through it, which would become the basis
Speaker 1: for electric loudspeakers decades later. Now, basically the idea is this,
Speaker 1: imagine you have a frame. So you've got a frame.
Speaker 1: Let's say it's a square frame. It's got sort of
Speaker 1: a circular opening in the middle of the square frame.
Speaker 1: Inside this frame, you suspend a coil of conductive wire,
Speaker 1: so it's spend it in such a way where it
Speaker 1: can swing towards the back of the frame or towards
Speaker 1: the front of the frame, but it cannot move up
Speaker 1: or down or side to side with respect to the frame.
Speaker 1: So it's if you're thinking of like the x y
Speaker 1: and Z axis axes. Rather, uh, the Z axis is
Speaker 1: what we're concerned with here, not the X Y. So
Speaker 1: it can move if you're looking dead on in the frame.
Speaker 1: It can move towards you or away from you, but
Speaker 1: not side to side or up or down. When you
Speaker 1: apply a magnetic field, you can induce electricity to flow
Speaker 1: through this conductor. The flow of electricity creates some magnetic field,
Speaker 1: and you can use the attraction and repulsion properties of
Speaker 1: magnets to move the coil back and forth within this frame. Now,
Speaker 1: Siemens did not originally intend for this invention to be
Speaker 1: used for acoustics. He had come up with this idea,
Speaker 1: but he wasn't thinking about loud speakers. He was just
Speaker 1: talking about this basic apparatus. But after Alexander Graham Bell
Speaker 1: patented the telephone in eighteen seventy six, Siemens was motivated
Speaker 1: to apply for a new patent for a non magnetic
Speaker 1: parchment diaphragm as a means of sound radiation on a
Speaker 1: moving coil transducer. He received his patent in eighteen seventy eight.
Speaker 1: And we call the coils on speakers that drive the
Speaker 1: speaker's motions a voice coil. So if you ever hear
Speaker 1: anyone talk about the voice coil of a speaker, that's
Speaker 1: the coil that is part of the speaker system. It's
Speaker 1: it's attached to the diaphragm of the speaker that makes
Speaker 1: the diaphragm actually vibrate. At this point, I need to
Speaker 1: mention there were numerous scientists, tankerers, and engineers amateur inventors
Speaker 1: who made numerous contributions to allowed speaker designs. Now I'm
Speaker 1: going to talk about just a few of them, because
Speaker 1: to cover them all would take a couple of episodes,
Speaker 1: and some of those contributions, while important, were of such
Speaker 1: a specific nature that would become kind of tedious pretty quickly.
Speaker 1: Just know, a lot of folks worked on this stuff.
Speaker 1: In the late eighteen hundreds and early nineteen hundreds, twenty
Speaker 1: years after Siemens received his patent for a voice coil
Speaker 1: speaker mechanism, this would be about eight In other words,
Speaker 1: there was a man named Oliver Lodge who filed for
Speaker 1: a patent in the United Kingdom for a loud speaker
Speaker 1: that included non magnetic spacers that were intended to keep
Speaker 1: the proper air gap between the inner and outer polls
Speaker 1: of a moving coil transducer, which would help prevent issues
Speaker 1: with the transducer getting stuck within the frame. In nineteen
Speaker 1: o one, John Strow suggested a conical paper diaphragm to
Speaker 1: act as the sound radiator, and went further to suggest
Speaker 1: such a design could be used so that the end
Speaker 1: of the cone stopped at the rim of the speaker
Speaker 1: in a flat section covered by a corrugated surface. So
Speaker 1: in other words, it's kind of like what a speaker
Speaker 1: cabinet looks like today. If you take a speaker cabinet
Speaker 1: that being what we commonly referred to as just a speaker,
Speaker 1: and you look at you can see you have a
Speaker 1: mesh covering of some sorts, probably made out of fabric,
Speaker 1: but it could be made of something else, and then
Speaker 1: through it you'll see the circles that represent the cones
Speaker 1: of the speaker drivers. Well, it was John Strow who
Speaker 1: actually said you could design a speaker in this kind
Speaker 1: of fashion, So that was back in nineteen o one.
Speaker 1: In nineteen eleven, Peter L. Jensen and Edwin S. Pridham
Speaker 1: founded the commercial wireless and development company Jensen and Britain
Speaker 1: would actually build a practical moving coil loudspeaker in nineteen fifteen.
Speaker 1: So people have been talking about this for decades, but
Speaker 1: this was the pair that built the first practical one,
Speaker 1: not just a prototype in a lab, but one that
Speaker 1: could actually be used out in the real world. Together,
Speaker 1: they created a public address system that would allow huge
Speaker 1: crowds of people to hear a presentation or music distinctly
Speaker 1: over loud speakers, and they called their system Magnavox. Later
Speaker 1: they would use that as the name of their company.
Speaker 1: They renamed their company Magnavox. And I'll have to do
Speaker 1: an episode on Magnavo Box at some point because it's
Speaker 1: a big company. It's been around for a long time.
Speaker 1: They've done a lot of important things. Jensen and Pridum
Speaker 1: attempted to patent their design with the intent of working
Speaker 1: with record companies and radio manufacturers, but they were denied
Speaker 1: their patents for those applications, which is why they instead
Speaker 1: focused on public address systems. In two engineers for General
Speaker 1: Electric named Chester W. Rice and Edward W. Kellogg applied
Speaker 1: for a patent for a dynamic loudspeaker in n They
Speaker 1: published their work in an article titled Notes on the
Speaker 1: Development of a New type of hornless Loudspeakers, and it
Speaker 1: was all on the Journal of ai E Transactions. Their
Speaker 1: design described what would pretty much be the foundation of
Speaker 1: all electric loudspeakers from that point forward. So in a
Speaker 1: bit i'll describe what it consists of and how it works.
Speaker 1: But first let's take a quick break to thank our sponsor.
Speaker 1: All Right, now, I'm gonna focus on the speakers themselves,
Speaker 1: and after we talk about speakers and how they work,
Speaker 1: we'll talk a bit about amplifiers, as that was a
Speaker 1: piece that was missing from the Rice and Kellogg loudspeaker.
Speaker 1: And yeah, I know that sounds like I'm talking about
Speaker 1: Rice Crispy treats, but no, uh. The the guys who
Speaker 1: got the patent for the Dynamic Electric loudspeaker were Rice
Speaker 1: and Kellogg, and the two mentioned in their article that
Speaker 1: there was a need for more work and amplification in
Speaker 1: order to get the volume levels you want out of
Speaker 1: a speaker. But we're gonna get to that in a
Speaker 1: little bit, so we'll put that aside for now. So
Speaker 1: if you were to take a speaker apart, and you
Speaker 1: have essentially was called a speaker cabinet, you would find
Speaker 1: that inside that speaker cabinet are one or more drivers,
Speaker 1: typically more than one if you're talking about a big
Speaker 1: stereo speaker. Now, a driver consists of a cone shaped frame,
Speaker 1: which is called a basket. The basket contains the other
Speaker 1: components of the loudspeakers, so they're all housed inside this frame.
Speaker 1: Attached to the interior of the frame is either an
Speaker 1: electro magnet or a permanent magnet. It just depends upon
Speaker 1: the speaker. In the early days of speakers, manufacturers almost
Speaker 1: always used electro magnets because permanent magnets were difficult to
Speaker 1: come by and thus they were very expensive. Also attached
Speaker 1: to this frame is a cone. The cone might be
Speaker 1: made out of paper or metal, or these days plastic.
Speaker 1: This is the diaphragm of the speaker. This is the
Speaker 1: part that vibrates and it's what pushes air molecules to
Speaker 1: propagate sound outward to the listener. It's typically in a
Speaker 1: cone shape that's sort of like a horn. It's depending
Speaker 1: upon those acoustics, uh, you know, the same acoustic properties
Speaker 1: of horn loudspeakers that I mentioned earlier. But there are
Speaker 1: some that are not in a horn or cone shape.
Speaker 1: Their dome shaped, or they might have a slightly different shape,
Speaker 1: but they work in largely the same way. They vibrate
Speaker 1: and push air molecules. This cone or diaphragm attaches to
Speaker 1: the suspension that's also known as the surround. The suspension
Speaker 1: is a rim of flexible material that's mounted on the
Speaker 1: end of the basket, So the the end that faces
Speaker 1: outward towards the listener. That's the side that the cone
Speaker 1: attaches to, so right there at the very end. So
Speaker 1: in short, we've got the suspension mounted to the end
Speaker 1: of the basket. Attached to the suspension is the cone.
Speaker 1: On the narrow end of the cone is the voice coil.
Speaker 1: That's the conductive wire that coils around the base several times.
Speaker 1: The coil also attaches to the basket through a ring
Speaker 1: of flexible material called the spider. He is our hero
Speaker 1: if you know that reference, so you'll let me know.
Speaker 1: But no, the flexible material is called the spider. Its
Speaker 1: job is to hold the coil in a position that
Speaker 1: is stable within the frame but still allows for that
Speaker 1: axial movement, to let it swing back and forth freely,
Speaker 1: or more appropriately, to vibrate backwards and forwards with relation
Speaker 1: to the frame. So, in other words, it's doing the
Speaker 1: job that Ernst Siemens described in his patent back in
Speaker 1: the eighteen seventies. The secret to making a driver work
Speaker 1: is all in electro magnetism. Whether the speaker is using
Speaker 1: permanent magnets or electro magnets on the basket, the principle
Speaker 1: remains the same. I'll talk more about the principle in
Speaker 1: our next episode, but for now we're going to conclude
Speaker 1: part one of How Speakers Work. If you guys have
Speaker 1: suggestions for future episodes of tech Stuff, I highly recommend
Speaker 1: you get in touch with me. You can do that
Speaker 1: by sending an email to the Text Stuff email that
Speaker 1: would be tech Stuff at how stuff works dot com,
Speaker 1: or you can draw me a line on Facebook or Twitter.
Speaker 1: The handle for both of those is text Stuff hs W.
Speaker 1: Don't forget we have an Instagram account, so make sure
Speaker 1: you follow us there. And I live stream these podcasts
Speaker 1: on Wednesdays and Friday, so if you want to watch
Speaker 1: me record live, go to twitch dot tv slash tech Stuff.
Speaker 1: You can join in on all the fun, jump into
Speaker 1: the chat room, make fun of me when I say
Speaker 1: weird things incorrectly, and then I have to make a
Speaker 1: deep noise so Tari nose to cut it out of
Speaker 1: the recording, and sometimes we forget to do that and
Speaker 1: you get to hear me say beep. It's like a
Speaker 1: giant bonus for everybody. Anyway, I record on Wednesdays and Fridays.
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