Continuing our history of Magnavox, we look at how the invention of the moving coil loudspeaker would form the foundation of the company. Oh, and also how the engineers of Magnavox figured out how to make noise-cancelling microphones for World War I airplane pilots.
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Welcome to tech Stuff, a production from I Heart Radio. Hey there, and welcome to tech Stuff. I'm your host job in Strickland. I'm an executive producer with I Heart Radio, and I love all things tech. It is time for us to continue our stories about Magnavox. So we're picking up where we left off from our last episode about Magna Vox. Uh. That point was where I rushed to explain where the name Magnavox came from. And so, in case you missed the first episode, yeah, I taught for nearly an hour and didn't even get to the company getting its name. I mean, I just kind of squeeze that in. In fact, we still have a little ways to go before the company officially becomes Magnavox. The too long didn't listen version of episode one, though I do think you should go back and listen to episode one. But the short version is that a much engineer named Peter Jansen and an American engineer named Edwin Prittum, previously employed by Dutch radio pioneer Valdemar Poulson, had partnered with money from Richard O'Connor, a candle and soap maker in the San Francisco area in the early ninet hundreds to create a radio company operating out of California. Bridham and Jansen were the engineers and the R and D department for this company, and they had created a voicecoil electro dynamic speaker which they hoped to patent, but they ran into a bit of a roadblock because it turned out there were other inventors who had previously patented similar ideas. They were, however, able to secure a patent specifically for the voice coil version of their invention. I explained how that worked in the previous episode, so don't worry. I'm not going to go into it here because I just did it earlier this week. But I will remind you that their version had a speaker, diaphragm, and an Edison phonograph horn, So in other words, you know, it wasn't like a speaker the way we see them today. It actually had a large physical horn attached to it to project the sound outward. Now, the first time they actually connected the components, you know, with the speaker and a microphone, the receiver and horn contraption let out a terrible noise. In fact, Ensign would later write a crack like the report from a gun came out of the horn, followed by a screaming, howling noise which was ear splitting and terrifying. This was, of course feedback, where as sound coming from the speaker gets picked up by the microphone and then fed back into the speaker you know, amplified, and then this goes on and on. It becomes a feedback loop. So Britam yelled to disconnect the battery before the whole house blew up. By then, the connection was already broken and the speaker went silent, and they eventually figured out what the problem was, so they mounted the speaker to the chimney of the bungalow they had in Napa. This was the headquarters for the company that would become Magnavox. In fact, according to one account, they even had Jenson's younger brother, Carl, up on the roof. Carl and it was his job to hold the loud speaker to the chimney because they were actually worried that it would vibrate so much that the speaker would shake loose and fall off the roof of the house. They ran a line down into the bungalow so that the transmitter would not be close to the speaker, and they pointed the speaker, you know, toward NAPA, and they talked into the microphone. According to Jenson, when Prindom used the microphone, it sounded as though quote, a supernatural colossus was shouting up the chimney end quote, and Prindom gave instructions that seemed kind of apocalyptic. He asked the residents to light the bonfires if they could hear him. Jensen reportedly dashed out the bunk below. He ran as far as maybe two kilometers according to Predom. He managed to set a personal record for fastest run, and Jensen discovered that he could still hear and understand Predom even a mile away from the bungalow. Predom would experience this as well. He hopped on a bicycle and pedaled off while Jensen spoke into the microphone. Suddenly, the fact that they originally thought this is a really limited use case technology kind of faded away, you know. They originally thought that the loudspeaker would be useful for public spaces like ballparks. In fact, making announcements at baseball games served as the motivation for developing it in the first place. They realized that their attempt at creating something with limited use was in fact way more powerful than they first anticipated, and it could be a real game changer. So they contacted Richard O'Connor, you know the money. O'Connor was flabbergasted that hearing this news, it actually took some convincing to assure him that they weren't just pulling his leg and telling him stories or exaggerating, so he finally believed them, and then he arranged to have stockholders travel out to Napa to see a demonstration of the loudspeakers for themselves, and that demonstration was beyond successful. The stockholders, amazed by what they heard, were excited, and Pridham and Jnston were essentially told that finances would no longer be a problem. It was at this point that Jnson and pried Um then debated on what to call their invention, and they had a few names under consideration. One of them was just loudspeaker, but Jansen felt that wasn't a very appealing name, even though, as we all know later on, that would become the generic term for the invention anyway. So then they thought maybe tele megaphone, which they dismissed they would later use that for a product. They also thought of a few other names, but ultimately they decided that they would use a couple of Latin words at to be the inventions name, and they wanted to call it a Great Voice, so like you know, as the great and powerful, like I said in the last episode. So that's why they called it Magna vox Great Voice, which we already know because I mentioned all that in the last episode, but I had the circle background to it. So the company, which at this point was still called the Commercial Wireless and Development Company or c w d C, got an influx of cash and the incident, Pridom continued to refine their design of their loudspeaker all throughout nineteen fifteen. They made tweaks to their design to improve the performance. They also created an all in one electric turntable with an electric toner arm our toning arm, and it had a loudspeaker housed in the cabinet of itself, so when the record turntable would play, the needle in the in the arm would actually create an electrical signal that would go to an amplifier that would go to the speaker. So this was a very early example of an electronic system that could actually play records back electronically, as opposed to just being a purely acoustic horn. To amplify sound that way, they would also occasionally play music out through the loudspeaker that was attached to the chimney of their bungalow, thus creating a sort of prerecorded concert experience for the area of NAPA. It was a little bit like a proto radio station, except of course, you weren't picking up radio signals. You weren't using an antenna to pick up radio. You were just hearing music that was blasting out of a loudspeaker attached to some dude's chimney, which I'm sure the time was novel and exciting and interesting. I would think of that today as being a gosh darn nuisance. Towards the end of nineteen fifteen, Incid and Priedam had created a loudspeaker powerful enough that it could be heard within a radius of seven miles of the loudspeaker, which is pretty darn powerful. But the demonstrations, while effective, were kept pretty local. And you know, it was nineteen fifteen, so word did not travel around particularly quickly. They actually dismissed the idea of exhibiting their loud speaker at the Panama Pacific World's Exposition, which was going on in San Francisco that year. They were actually they were worried if they showed it off at a big exposition before they had really started to land, you know, deals with customers, someone else might go along and copy their design and then beat them to the market. They finally arranged for a more formal exhibition of the technology in mid December in nineteen fifteen. They wanted to do it at the at a stadium that was located in Golden Gate Park, and despite the fact that the weather was lousy and these ding dang derned kids were in the park play in football, the demonstration impressed the invited audience. One journalist, Edgar Gleeson wrote about in the San Francisco Bulletin and positively gushed about the loudspeakers capabilities. A couple of weeks later, Jansen and Pridum set up by a loudspeaker for a Christmas event in San Francisco's City Hall. They actually hid the loudspeaker on a balcony and they put a flag in front of it because they were still worried that someone might, you know, get a good look and try to copy their design. That event drew a pretty huge crowd somewhere in the neighborhood of a hundred thousand folks by one estimate. And again this demonstration went over really well, and after a few more similar demonstrations, the c w d C found itself a potential partner. This was the distributing arm of a company called the Sonora Phonograph Company. This attempted to establish itself in the phonograph slash early record player industry, but Sonora had its own challenges, namely that the Victor Talking Machine Company was jealously keeping a grip on lateral recording of phonographic discs, which forced Sonora to go with the alternative vertical cutting of phonographic discs. But you might wonder, what the heck does that even mean. Well, imagine a modern record. If you've ever seen a vinyl record, right, it's got these grooves that are in it. Well, you know, this is all about how you record vibrations onto these these records, these rotating discs of material. So let's imagine the grooves in a record are kind of like a trench. So imagine you're inside a trench with lateral cutting, the walls of the trench jut in and out. They you know, come further into the trench. Sometimes they go a little bit out of the trench. Uh. Sometimes things get a little tight. Sometimes it's you know, relatively not tight. This makes you know, a needle or stylist that's traveling through the trench vibrate laterally as it's moving through the groove, like the walls are pressing the needle to go left or right, depending on how the walls of the trench are shaped. Those vibrations then go to the rest of the device to produce sound. And I'm not going to go through all of that again because I'm more or less covered in the last episode. Now, that is lateral cutting, and that's what the Victor Talking Machine Company had a tight hold on. So Sonora with vertical cutting. So now imagine you're in that same trench. But the walls are pretty much smooth, right You've you know, they still curve because you're on our you know, around platter, but they're smooth walls. It's the floor of the trench that's really bumpy and a properly designed needle would move up and down as it traveled through the groove, and that's what would generate the sound you would hear. Uh. This method produced lower quality recordings than lateral cutting, and also it would eventually, you know, make the record were out. Actually, you typically would have the record were out faster than you would if you were using a record that had lateral cutting, because the needle is traveling the same up and down path over and over again and wearing it down over time, so there were disadvantages to it. Anyway, the Sonora Phonograph Company had a distribution division in Oakland, California, which is in the San Francisco area. The C W d C and Sonora discovered that their goals were aligned, and so the two companies formed a partnership and they would merge together, forming an all new company in nineteen seventeen, and that company would of course take on the name Magnavox. Now, when I say Sonora and uh C w DC merged, keep in mind this was one division of Sonora. It wasn't the full Sonora Phonograph Company, but their distribution arm. So while you could argue that Magnavox is history stretched back to around nineteen o nine or so. The official founding of the company named Magnavox would happen nearly a decade later. This also means that Magnavox the Loudspeaker is actually older than Magnavox the company. The loudspeakers celebrated its on birthday. In Magnavox the company was, you know, ninety eight years old at that point, if it were still its own independent company. But that's just foreshadowing. Richard O'Connor, who had headed up the c w d C, would become a director of Magnavox. Frank Steers, who came over from Sonora, would eventually serve as president for Magnafox. As for Priedom and Jenson, they became co chief engineers. And that might sound a little bit weird for two people to serve in the same executive role. We've seen it a few times in tech companies where you had more than one person essentially inhabiting what would normally be a single person role, and it certainly could lead to problems should the two engineers disagree on the direction of development. So Jansen and Priedam had come up with a fairly clever approach to leadership. They alternated one month Jensen would serve as chief engineer and the next month Priedom would do it, and then they'd go back and forth. This was to avoid issues where a subordinate could potentially get conflicting directions from the two leaders. So it was a practical solution to a real problem. Now you might remember that the year at this point is nineteen seventeen, and that's the same year that the United States entered into World War One. We didn't call it World War one at that point because that would be way too pessimistic. Accurate, but pessimistic. One of the things that tends to happen in wartime, however, is that companies in nations that are embroiled in the conflict will frequently pivot towards creating stuff to aid in the war effort, not always by choice, sometimes mandated by the governments of those countries. Magnavox would be no exception to this trend, and the young company, having just branded itself, would find itself producing technology to help support the United States military in World War One. So Magnavox, which had been preparing to create a commercial version of the electronic phonograph that Printum and Jansen had designed a couple of years earlier. Put consumer electronics on the back burner. The company participated in trials to see if loud speakers could be used to communicate from a ground station to a plane flying overhead. After all, early tests had shown that the loudspeaker could project sound a really long distance, like up to seven miles. But as I'm sure you already suspected, it turned out that the planes were just way too noisy, and the tests ended up proving that loud speakers would not be an effective communication tool for ground to air transmissions. However, Jansen and pried Um experimented with microphone and speaker technology and found one application that would prove to be really useful during the war. More on that after we come back from this quick break. So what was the invention that Predoman Jensen devised that would be a huge help in World War One? Well, it was a noise canceling microphone. You see, the planes were so loud that it was really hard to communicate inside one, whether you were a pilot trying to use a radio to talk with ground, or maybe you were part of a larger aircraft like a bomber, and you're trying to communicate inside a single aircraft. The engine and the propeller noises were just too intense for easy communication. Also, remember this is World War One. Some of these aircraft were open cockpit aircraft. It was just really hard to hear one another. So the engineers needed to figure out a way to compensate for this, and at first they tried to figure out a way to isolate and thus exclude the noise, but everything they tried failed. The noise was just too powerful and there wasn't any way to cancel it out. And then, out of desperation, tried something that is at least at first counterintuitive, or at least I found it counterintuitive. And what they did was they took a microphone and they essentially stripped it down. They removed pretty much everything that shielded the microphone, so that now the diaphragm of the microphone was exposed on all sides. And this worked. Why did it work? Well, let's consider a sound for a second. And I know I talked about sound a lot on this show, but sound is vibration, and typically we're talking about fluctuations and air pressure, air molecules, vibrate, and those vibrations propagate outward from the source of the sound, and with microphones, we usually designed the microphones so that they channel sound from a specific direction for the purposes of transmitting that vibration to a diaphragm, and then we end up sending that signal onto amplifiers and then perhaps a speaker to amplify that sound while by removing all the shielding around the diaphragm, what the incident printum did was they equalize the air pressure from all the noise. The noise from the airplane was essentially hitting both sides of the microphone diaphragm, so it was canceling out the effect. It would be kind of like if you had two people of equal strength who were just pushing against each other, they would be at a standstill. They wouldn't no one would gain advantage over anyone else. Now, if you designed this kind of microphone in such a way that a person who was speaking into it was only affecting one side of that diaphragm, that person's voice would come through right. All the noise would be pushing on both sides, so it cancels it itself out. But sound coming from your voice. If it's only hitting one side, it's causing the diaphragm to actually vibrate. Those vibrations get picked up and converted into electric signal and there you go. So unlike the airplane noise, the vibrations only come from one side when you're talking about using it as a microphone. So the micro phones had these attachments that would fit onto leather helmets, so you you wear it like right in front of your mouth. Um. In fact, when you look at pictures of this or illustrations of it, uh, they look kind of like like something out of a science fiction novel, right, because you've got this weird little round microphone position directly in front of the mouth of the person wearing the helmet. Um. That would allow them to communicate with the ground or with each other inside the same plane. Of course, the microphones were paired with speakers that were mounted in headphones, and these also attached to the leather helmets. So this ingenious system, which was taking advantage of physics, allowed greater communication inside planes and drastically increase their effectiveness. Now, that was not the only thing that Magnavus designed for the US military during World War One. The company also created public address systems that would be used aboard naval vessels, particularly to allow those who are working in very NOI easy environments like engine rooms to be able to hear announcements and other communications from the bridge. Production increased to the point that Magnavox had outgrown the bungalow. The company relocated to the San Francisco area sometime around nineteen. Most of the employees at this time were women. You know, they weren't drafted to go fighting the war, So women were the people who were building radio junction boxes and working with circuitry. They were the ones building the radio systems that pilots in World War One were dependent upon. After the war, Magnavox continued to create technology for ships with the design of watertight telephone systems. And it looked for the moment like the loudspeaker, which was the thing that launched the company in the first place, wasn't really gonna go anywhere. But that was about to change. See leading up to the US ratification of the Treaty of Versailles and the formation of the lead Egue of Nations, US President Woodrow Wilson had to conduct a campaign, a national campaign to promote the post war peace effort and to get support for the Treaty of Versailles. He was encountering resistance to the US signing or ratifying the Treaty of Versailles out of Congress. So his idea was, well, let's go to the American people and if they support these efforts, then Congress is going to have to go along with it, or else they're going to find themselves voted out of office. So he needed to get this groundswell of support for the ratification process, and he was supposed to travel to San Diego and make an address in what was called City Stadium it was later known as Balboa Stadium. But Wilson's health was in serious decline and his doctors were advising him not to be outside for long periods, and so it looked like the President was going to have to cancel his appearance because he was going to just show up and speak inside a stadium that was, you know, exposed to the elements. Well, the city leaders of San Diego weren't too keen on the idea of, you know, Wilson canceling, so they wanted to find a work around. The notion was that Magnavox would design a loud speaker system and they would install it in the stadium, and Wilson would appear, but he would be inside a glass booth while a lot of a lot of sources actually called it a large glass cage, which seems a bit ominous to me. And so he would be standing in there, looking out through the glass, but addressing the crowd through a microphone system. The incident was actually across the country in Washington, d C. At this point he was attending meetings with various government officials regarding you know, Magnafox as other projects, and so it kind of filled a printum to create and install the system in Balboa Park. So he used a pair of microphones. They looked kind of like loud speakers. They each had a horn. So in this case, the horn's purpose was to funnel sound into the microphone, you know, towards the diaphragm, rather than propel or splify sound outward. He mounted loudspeakers on top of the glass booth that pointed towards the audience. At this point, vacuum tubes were used in amplifiers. So it's a good time to remind ourselves how vacuum tubes work and how amplifiers work. So a vacuum tube looks and somewhat behaves a bit like a light bulb, doesn't incandescent light bulb. So they are glass tubes, and inside these glass tubes you have components that look a bit like the filament you would find in an incandescent bulb. But rather than you know, a filament that lights up, what you have are you've got a cathode and an anode that are separated by a gap inside the tube. And again there's no air inside this tube. That's the whole vacuum part of vacuum tubes. So when you supply an electric signal to the cathode, the cathode begins to heat up, and as that happens, the metal in the cathode begins to release electrons. This is a process. It's called thermionic emission, and in fact another name for vacuum tubes would be thermionic valves. If you then apply a positive electric charge to the anode side of the vacuum tube, the negative electrons from the cathode side are attracted to the anode because opposite charges attract, so the electrodes will then travel from the cathode to the anode, and this creates a current. This is a basic diode vacuum tube, and it allows current to flow only in one direction, from the cathode side to the anode side. You can't reverse it, so this is a way of creating direct current in that In that sense, amplifiers will have a third electrode. So you still have the cathode which is emitting electrons because it's heating up. You still have the anode, which, once you apply a positive voltage to it, will attract those electrons. But between these two you have your third electrode, and you've got what is called a control grid. So unlike the end ode, which is typically shaped like a plate, the control grid is like a mesh or a net, and by applying a voltage to the grid, you can control the flow of electrons from the cathode to the anode. So if you were to apply a negative voltage to this grid, it would act like a repellent, right because electrons are negatively charged, So if the if the net between the cathode and the anode also has a negative charge, that's going to repel electrons. Only a few electrons might make it through, you would dampen the signal. But if you were to apply a positive charge to the control unit, then you would increase the flow of electrons from cathode to anote. You would amplify that signal that was coming from the cathode. So if you were to feed an electric signal from say a microphone, to the cathode side in a normal diode vacuum tube, the current would form between cathode and anode, and the signal you would get out would be pretty much the same signal that you put into it slightly less because you would lose some some energy in this case. But if you were to use a tryode, if you were to use a vacuum tube that had a control grid, you could apply a strong positive charge to the control grid. This would create a stronger flow of electrons from cathode to anode and thus amplify the incoming electric signals. So what you would get out would be stronger than what you put in. Now, I should clarify that, I mean the signal, the base signal that is coming out would be stronger. It's not like there's some magical way where we just boost the amount of electricity, and we didn't put forth any more effort. More effort is being put forth. It's just being put forth at the control grid part of the vacuum tube. But in a way, you could just think of this as just it's a way to boost the energy of an electric signal. So the vacuum tube and its applications pretty much place the old arc transmitters that Jansen and Pritam had been working on a decade earlier, and they were really effective as amplifiers. And there are musicians who to this day swear by vacuum tube amplifiers. They will only use those with their equipment. They'll hook up their musical instruments to vacuum tube amplifiers, even though we now have transistor based amplifiers. And I'm not saying that the musicians are wrong, but there are a lot of different factors that go into whether or not the sound you get out of an amplifier is good, and it's not just whether it's vacuum tube versus transistor. But anyway, let's get back to, you know, the Magna vox system. Around fifty thousand people attended President Wilson's address. Pridam warmed up the crowd by playing some recorded music through the system before Wilson's arrival, and the whole thing was, you know, nearly a shambles because Printam noticed that just as the President was getting ready to speak, smoke was starting to come out of the amplifier. So him took a look in the amplifier and he noticed that one of the two vacuum tubes was severely overheating. It was apparently red hot, so he very quickly removed that one, and fortunately the other tube was sufficient to amplify the signal and send it to the loudspeakers. The speech reportedly went over very well. Wilson, despite being visibly weak with his frail health, found the crowd receptive to his speech, so much so that he reportedly had to pause several times for applause, and the experience drew national attention. Reporters waxed poetic about how the loudspeaker system allowed almost everyone in attendance to be able to hear and understand the speech, which was a pretty big feat for the time. Breadham, however, observed a few things that he wanted to fix in future attempts. For one, he noted that the President's voice sounded kind of hollow, and he figured out that part of this problem was that Wilson was in this big, old glass box. Uh. And when I say big, I mean pretty big. The booth was large enough to hold several dozen people, up to fifty I think. According to one source, Predam surmised that the sound of Wilson's voice was bouncing off the walls inside the booth and thus creating an echoe effect. And he later wrote, quote, it was a long time before a solution was found for this trouble, and that solution was never to have any surfaces near the microphone that would permit echoes end quote. And this is kind of similar to Predam learning the hard way about microphones and speakers and feedback. Also, this is something that the audio business pays very careful attention to to this day, making sure not to record in areas that have a lot of hard surfaces that could, you know, sound could just bounce off of. This is also why my producer Tari really wants me to hang up blankets all in my office at home to dampen sound, because my desk is near a corner of the room and she wants to get rid of the little teeny tiny bit of echo that manages to come through the recording Hey Tari. Anyway, Wilson's speech when which took place on September nine, nineteen nineteen, would be the event that would propel Magnavox into fame. Magnavox would also play a part in other notable public speeches and performances. When the future Edward the Eighth visited San Diego, he too went to the stadium and gave a short speech over the Magnavox loud speaker system, this time with Jansen there to run things. And when William G. Harding ran for president, he used the Magnavox loud speaker system to deliver speeches to crowds h though he did later switch allegiances and used A T and T S loud speakers during his inauguration. In fact, A T and T was really putting a hurt on Magnavox because it turns out that incident prinom were pretty right to worry about folks copying their invention, and A T and D was not just producing loudspeakers and securing contracts to large public events. They were all also in the business of producing vacuum tubes, which Magnavox at that point was not doing. And because Magnavox was reliant upon vacuum tubes for amplification, that got a little testy. So Magnavox shifted its focus and really got into the consumer electronics market. And what would help it would be the birth of the broadcast radio station. And that's because radios, as in the consumer product that you would use to receive and play radio broadcasts, needed loudspeakers, as did phonographs and other sound devices. And so Magnavox, after a bit of a delay because of World War One, began to develop consumer products, or at least components that would go into consumer products. We'll talk about it more after this quick break. All right, we're now in the early nineteen twenties, a period that would be transformative for Magnavox. The company was performing pretty well, is generating a good deal of revenue. The emerging market of radio would make radio sets. They must have home appliance, positioning Magnifux well for that market, or at least it would appear to I should also add that initially radio sets were extravagantly expensive. In fact, if you were to look at the marketing materials from around that time, you would see ads for radio sets that appeared to be targeting the wealthy, complete with illustrations of people in formal attire dancing elegantly next to our radio receiver. And the radio receivers also looked a lot different from the radios of today. I mean, we have transistors in our radios today, so they were much larger. But they also incorporated those acoustic horns that were attached to the actual speaker, and this was sort of like the old gramophones or the old phonograph horns, and thus they looked a lot like those older pieces of technology. In Magnifux introduced the t r F five. It was claimed to be the first single dial radio, as in the first radio to use a single dial in order to tune the radio to a specific frequency. And I say claimed to be because there are several companies that all argue that they were the first to introduce the first single dial tuner, but we can at least say that Magnavox's version was one of the earliest and possibly the first one. The TRF and t r F five actually means tuned radio frequency, and the reason the single dial. Thing is important is that earlier TRF radio sets typically had two or even three dials that you need to use to tune the radio to pick up specific frequencies. In other words, to tune the radio to the right station. So to get a radio station to come in clearly, you had to make sure that each dial was tuned just right. The Magnavox introduced a set that connected all the stage tuning capacitors to a single dial. And I think it's a cool idea to talk about the basic components of a TRF radio set. All Right, so you got a radio receiver. What do you need in order to actually, you know, like grab radio waves out of the air and then play them on a speaker. What are the components you need? Well, first you kind of need an antenna. The antenna is what picks up the radio wave radiation. So the electromagnetic radiation, well, hit the antenna and it causes electrons and the antenna to start to vibrate. Essentially, you're creating a current to flow through the antenna up and down the antenna. Now, lots of stuff makes radio waves, and so how do you select what you want to listen to? You don't want to just open up the floodgates and listen to every single radio frequency. It would just be noise. You need to use a tuner or a tuned circuit. This is a way for your radio to zero in on the specific radio transmission and ignore everything else. If you take the A M frequency band that ranges from around Hurts up to sixteen fifty killer Hurts, and each channel of radio transmission has a bandwidth that's ten killer Hurts wide. So you need a way to say, I want you to play the signals transmitted at this frequency. Let's say it's killer Hurts and ignore everything else in the A M spectrum. Otherwise, again, you would just get everything it would it would be incomprehensible. If you remember from our last episode, we talked about how spark gap transmitters are kind of like a shotgun blast of radio frequency radiation, and the reason they're illegal today is because if you know you had one operating near you and it had a sufficient amount of power behind it, it wouldn't matter if you tuned your radio properly. A spark gap transmitter could overpower the signal and you would just get blasted by you know, it's almost like jamming your radio, although it wouldn't necessarily be the reason why someone was using a spark gap transmitter in the first place. Anyway, tuners work on the principle of resonance. Tuners will resonate with and thus amplify signals that they get tuned to, and they use capacitors and inductors in order to achieve this. Now, I'm not going to go into all the details around that. It's a lot of tech and a lot of science that I think goes beyond our our podcast episode, but it's what you know, the dials on the TRF radio set we're all meant to do. You were to set the inductors and capacitors to specific levels in order to tune into a particular frequency. Well, the signal coming from the antenna typically is pretty weak, so the tunor circuit often is paired within our f amplifier. And you know I just described how amplifiers work. It's essentially the same thing. You've got this incoming signal, but it's really weak, so you use an amplifier to boost the strength of that signal, and you then take that signal and pass it to the X component, which is typically a demodulator, or sometimes it's called a detector. Now, the purpose of this component is to separate out the actual audio signal from the carrier wave that the audio signal was traveling on. So with a M we program sound onto a carrier wave by changing the amplitude of that wave and the change of that of that amplitude of that wave over time. That's the encoding of the audio we're putting over the signal. So AM actually stands for amplitude modulation. So this is kind of like, you know, decoding a coded signal. That's the purpose of the demodulator to reverse the process that we used in order to kind of imprint an audio signal onto a carrier wave. Next, you've got a couple of audio amplifiers in order to again boost the power of the outgoing signal. Uh, the outgoing in this case is outgoing to a speaker. So you've at your radio signal that comes in. We boost that we demodulated. Now we have the audio signal, we need to boost that before we send it to the speakers. Otherwise the signal might be too weak to make the speaker work and you would either end up with a very quiet transmission even if you turn the volume all the way up, just because the signal would be so weak, or you might not even be able to hear anything at all. The earlier TRF radios were pretty complicated with all those dials, and it restricted radio mostly to hobbyists, so they were the ones who were willing to put in the work to understand how to tune a radio and get a signal. But your average person doesn't want to sit there and fiddle with dials for thirty minutes just so that they can listen to their stories. So Magnavox's invention of a single dial radio reduced the complexity and became one of the reasons that the radio receiver could become a household appliance. So it was a pretty big success for Magna Vox on that level. But as we'll learn, the radio set business would be a different matter for Magnavox, and in nineteen twenty four, Richard O'Connor, the candle and soapmaker who had funded the original C W d C company that had turned into Magnavox, passed away. O'Connor had been acting sort of as a mediator between the engineers Jensen and Pridum and the executives who were in charge of Magnavox. But with him gone, there was no one to protect the engineers, and because of that, in nine Peter Jensen handed in his resignation. He had bristled under the directives of the business leaders. He felt that they were uh, they didn't have a full understanding of what he did, and that they were making dumb decisions, so he decided to part ways. That meant the partnership of Jensen and Pridum, which had spanned a decade and a half, came to an end. Jensen would go on to found his own radio manufacturing company. He would stick with that until nineteen forty two, and then he sold off his ownership of that business. He had other issues with stakeholders, kind of similar to what was going on at Magnavox. Like it was a constant struggle between leadership and his vision as an engineer. So once he sold off his interest in that company, he went on to found another company called Jensen Industries, and he would run that until nineteen sixty one, when he passed away. He also received a knighthood from the King of Denmark in nineteen fifty three. Now In our next episode, we'll go back to Magnavox and we'll talk more about some of the missteps the company made that would end up putting it in a pretty precarious position. And that was even before the stock market in general took a total nose dive. As as you know, if you've been paying attention like we've been creeping up the nineteen twenties, uh, that means that pretty soon we're gonna hit the stock market crash and the Great Depression, and that would have a pretty profound effect on many companies, including Magna Vox. But we will explore that in the next episode. For now, we're going to put the lid on this. We'll be back next week we list some more Hope you're enjoying the series so far. If you have any suggestions for topics I should cover in future episodes of tech Stuff, feel free to reach out to me. The best way to do that is to send me a tweet, and the handle for the show is text Stuffs hs W and I'll talk to you again really soon. Text Stuff is an I Heart Radio production. For more podcasts from my Heart Radio, visit the i Heart Radio app Apple Podcasts or wherever you listen to your favorite shows,