October 29, 2021 • 41 mins
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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Episode Transcript
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Speaker 1 (00:04):
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
(00:26):
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
(00:46):
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
(01:06):
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
(01:28):
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
(01:48):
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
(02:11):
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.
(02:35):
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
(02:55):
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
(03:16):
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.
(03:39):
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
(03:59):
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,
(04:22):
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
(04:43):
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
(05:07):
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
(05:29):
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
(05:52):
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,
(06:12):
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.
(06:34):
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
(06:55):
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,
(07:18):
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
(07:38):
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
(07:58):
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
(08:20):
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
(08:42):
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,
(09:06):
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
(09:27):
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
(09:48):
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,
(10:11):
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.
(10:34):
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
(10:54):
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,
(11:15):
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
(11:36):
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
(11:57):
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
(12:17):
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
(12:40):
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
(13:04):
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
(13:27):
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
(13:49):
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
(14:10):
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
(14:32):
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
(14:54):
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
(15:15):
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
(15:39):
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
(16:07):
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,
(16:27):
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
(16:48):
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.
(17:10):
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
(17:32):
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
(17:56):
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
(18:18):
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
(18:38):
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
(19:00):
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.
(19:22):
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
(19:46):
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
(20:07):
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
(20:28):
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
(20:50):
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
(21:11):
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
(21:34):
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
(21:55):
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
(22:17):
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
(22:40):
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
(23:03):
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
(23:25):
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
(23:49):
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
(24:09):
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,
(24:30):
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
(24:51):
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.
(25:15):
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,
(25:39):
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
(26:00):
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
(26:21):
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.
(26:42):
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
(27:02):
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
(27:22):
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
(27:44):
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,
(28:08):
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
(28:28):
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,
(28:51):
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.
(29:13):
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
(29:33):
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
(29:55):
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
(30:18):
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
(30:42):
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.
(31:05):
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
(31:27):
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
(31:55):
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
(32:16):
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
(32:36):
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
(33:01):
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
(33:22):
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
(33:43):
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.
(34:06):
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
(34:27):
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
(34:49):
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.
(35:10):
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
(35:31):
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
(35:51):
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,
(36:14):
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
(36:37):
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
(36:59):
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
(37:19):
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
(37:41):
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
(38:04):
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.
(38:24):
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
(38:46):
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
(39:09):
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
(39:33):
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,
(39:55):
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
(40:17):
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
(40:39):
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
(41:01):
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
(41:21):
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.
(41:44):
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,
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
(00:26):
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
(00:46):
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
(01:06):
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
(01:28):
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
(01:48):
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
(02:11):
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.
(02:35):
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
(02:55):
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
(03:16):
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.
(03:39):
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
(03:59):
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,
(04:22):
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
(04:43):
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
(05:07):
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
(05:29):
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
(05:52):
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,
(06:12):
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.
(06:34):
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
(06:55):
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,
(07:18):
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
(07:38):
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
(07:58):
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
(08:20):
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
(08:42):
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,
(09:06):
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
(09:27):
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
(09:48):
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,
(10:11):
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.
(10:34):
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
(10:54):
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,
(11:15):
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
(11:36):
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
(11:57):
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
(12:17):
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
(12:40):
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
(13:04):
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
(13:27):
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
(13:49):
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
(14:10):
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
(14:32):
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
(14:54):
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
(15:15):
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
(15:39):
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
(16:07):
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,
(16:27):
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
(16:48):
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.
(17:10):
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
(17:32):
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
(17:56):
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
(18:18):
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
(18:38):
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
(19:00):
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.
(19:22):
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
(19:46):
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
(20:07):
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
(20:28):
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
(20:50):
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
(21:11):
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
(21:34):
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
(21:55):
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
(22:17):
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
(22:40):
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
(23:03):
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
(23:25):
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
(23:49):
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
(24:09):
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,
(24:30):
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
(24:51):
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.
(25:15):
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,
(25:39):
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
(26:00):
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
(26:21):
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.
(26:42):
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
(27:02):
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
(27:22):
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
(27:44):
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,
(28:08):
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
(28:28):
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,
(28:51):
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.
(29:13):
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
(29:33):
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
(29:55):
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
(30:18):
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
(30:42):
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.
(31:05):
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
(31:27):
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
(31:55):
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
(32:16):
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
(32:36):
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
(33:01):
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
(33:22):
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
(33:43):
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.
(34:06):
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
(34:27):
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
(34:49):
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.
(35:10):
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
(35:31):
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
(35:51):
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,
(36:14):
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
(36:37):
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
(36:59):
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
(37:19):
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
(37:41):
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
(38:04):
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.
(38:24):
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
(38:46):
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
(39:09):
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
(39:33):
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,
(39:55):
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
(40:17):
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
(40:39):
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
(41:01):
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
(41:21):
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.
(41:44):
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,
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Oz Woloshyn
Karah Preiss
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