eight-foot Tesla coils owned by Masters of Lightning
produce an array of giant sparks (Copyright
Masters of Lightning).
I've always found the idea of using objects in
unconventional ways very interesting. For example, way back
in 1920 a Russian engineer named Léon Theremin was doing some
experimentation for the government with proximity sensors. These
are devices that put out an electromagnetic field and can sense
when an object interferes with that field though no physical
contact with the sensor has been made. Proximity sensors have
a lot of interesting uses. For example, airplanes can use them
to detect if they are too close to the ground. Some cars have
been outfitted with them to detect how near they are to objects
when backing into a parking space. A less benign application
is to put the proximity sensor into an anti-aircraft shell.
This enables the shell to explode when it gets anywhere close
to a plane. The shrapnel from the blast will damage the aircraft
whether the shell itself would have hit the plane or not.
Theremin looked at the tubes, wires and antenna
he was assembling to build the sensor, changed a few things
and came up with a completely new use: A musical instrument.
The Theremin, sometimes also known as an aetherphone,
etherophone or Thereminophone is thought to be the
first electronic instrument ever made. It is certainly the first
musical instrument of any type that could be played without
being touched. The Theremin looks a lot like a small box with
those old rabbit-ears-like TV antennas, only one antenna sticks
straight up and the other one sticks out to the side and loops
back to the box. To play it, you wave your hands close to the
antennas. One controls the pitch - whether the sound is high
or low - and the other controls the volume - whether the sound
is loud or soft.
The Theremin produces a rather eerie tone, sort
of like the sound you get when trying to tune in an old radio.
Theremin's invention (or other instruments working on similar
principles) have been used in a number of science fiction movie
soundtracks including the original The Day the Earth Stood
Still and Forbidden Planet. You can hear an Electro-Theremin
(a variation of the Theremin with a different control mechanism)
in the Beach Boys 1966 classic song Good Vibrations.
The Theremin also inspired inventor Robert Moog to build his
ground-breaking Moog synthesizer in the 1960's which, in turn,
was to start a revolution in sound production that changed popular
Just recently I came across another group of innovators
who are again using electrical parts in unexpected ways to make
melody. While I'm not sure their work will inspire a revolution
in music, it is still kind of cool in a geeky, science way.
The device they are using is a Tesla coil, a form
of transformer invented by the mysterious, genius Nikola Tesla
in 1871 (For more information on Nikola
Tesla and his inventions see our bio page on him). The Tesla
coil takes electricity and steps it up to very, very high voltages.
It also turns it into an alternating current. This means that
instead of the electricity flowing in only one direction (which
is known as direct current or DC), it first moves forward, then
reverses and moves backwards, then switches to forward again.
The number of times per second it does this is known as the
The electricity in your house is an alternating
current (AC) that makes this little cycle sixty times a second.
Using AC has a number of advantages, including allowing electricity
to be more easily sent over long distances. Without AC, a small
city would need dozens of power plants scattered across the
town to light everybody's home.
The Masters of Lightning Tesla coils play the theme
from Ghost Busters.
In a Tesla coil the AC is cycled not just sixty
times a second, but up to 2 million times a second. The
transformer itself usually includes a base that sits on the
floor, a tube which extends up from the base, and at the top
a donut-shaped, metal structure mounted on the tube. The transformer
has two "coils" of wire, the primary one on top of the base
and the secondary one in the tube. As the transformer charges
up the secondary coil with high voltage, high frequency electricity,
an electro-magnetic field forms around the top where it is connected
to the donut. High voltage currents in the field can actually
break out into the air from the donut and tear apart the air
molecules creating giant, high voltage sparks that look a lot
like lightning. It's an impressive sight.
Tesla used his transformers for experimentation
and built one at this laboratory in Colorado that could create
sparks one hundred feet in length. Today, Tesla coils are mostly
built and owned by hobbyists just for fun or by museums that
use the coils for public education demonstrations.
At this point we should clarify the difference
between a Tesla coil and a Van de Graaff generator. Van de Graaff
generators are also built by hobbyists and used by museums for
demonstrations. They are vaguely shaped like a Tesla coil in
that they have a base with a vertical tube topped by a metal
sphere. When I was a kid, my elementary school class would visit
our local science museum, The Franklin Institute, and they would
always select a little, blond, long-haired girl to participate
in the Van de Graaff demonstration (blond hair is thinner and
lighter making for a better show). They would have her climb
up on an insulated box and place both of her hands on the metal
sphere. Then they would turn the generator on and it would build
up a positive, static electric charge on the ball, and because
she was touching it, on the little girl too. Moving a metal
wand that was oppositely charged around her head, the demonstrator
would cause her long hair to stand up on end because it was
positively charged and the wand was negatively charged and the
two would attract. This would give the poor little girl the
ultimate bad hair day much to the delight of her classmates.
Dr. Zeus explodes hydrogen-filled balloons with sparks.
A Van de Graaff generator is safe enough to let
a child touch because even though it develops some very high
voltages, it only supports a very small current (or flow) of
electricity. A Tesla coil, however, will often support both
a very high voltage and a significant current and therefore
can be very dangerous. Hobbyists and professionals give them
a very wide berth when they are operating, though for years
people believed that the electricity from a Tesla coil would
only flow across the top of their skin, not doing internal damage.
Studies have shown this not to be true and the only reason someone
touching a streamer from a Tesla coil isn't screaming in pain
is that the high frequency is too fast for the human nervous
system to follow. While it is really rare for anybody to be
killed by a Tesla coil, getting zapped isn't good for you either
and there is always a small chance of a fatal accident.
Like all hobby enthusiasts, people who build Tesla
coils for fun have their own moniker. As Star Trek fans are
referred to as "Trekies" or "Trekers" (depending on who you
ask) Tesla coil hobbyists are known as "coilers." And just like
Trekers, they have their own meetings and conventions where
they can dazzle each other with new tricks in the field.
What I found interesting is that in the last few
years people have figured out how to turn Tesla coils into musical
instruments. The device has been given several names, but my
favorite is the Zesuaphone: a play on the sousaphone
with the Greek God's name substituting for that of the musician
John Philip Sousa.
How does a Zeusaphone work? My theory was that
it operated a bit like an AM radio station which uses the modulation
of the height (amplitude) of a carrier wave to carry a sound
signal. With the coil I figured that they must use the AC as
a carrier wave. If I was right, this meant that they could do
multiple notes at once. I emailed Jeff Larson, a pioneer in
the field, to see if this was true.
Zeus, Terry Blake, plays with lightning.(Copyright
"The sound we are making with the Tesla coils
is produced by turning the coils on and off at an audio frequency,"
Larson wrote back. "Each time the coil gets turned on there
is a bang. If you want a concert A you do that four hundred
and forty times per second. A computer does this with ease.
Four hundred and forty bangs per second sounds to our brain
like a tone of concert A. So from that you can see that it is
not like AM radio."
So, there goes my theory about amplitude modulation.
I asked Larson if it was still possible for the instrument to
do multiple notes at once and he replied.
"It is possible to do more than one note at a
time. We usually do not do more than two notes on one coil,
because it starts to sound bad and it draws a tremendous amount
of power. Each coil can draw over 60 amps at 240 volts. This
past weekend I saw one of the coils drawing over 80 amps."
That's quite a bit of electricity. A typical
electric dryer at 240 volts only draws about 20 amps. I can
see why they recommend giving these sparks a wide berth.
With the Show!
At least two groups have built shows around musical
Tesla coils. Arc Attack, which hails out of Austin, Texas,
and Masters of Lightning from Illinois. Larson is a member
of Masters of Lightning along with Terry Blake and Steve
It's Steve Ward's design of this particular type
of Tesla coil that makes the music possible. To control when
the coil "fires" most versions use a device called
a "spark gap." When voltages have built up to a high
enough level to jump the distance from one electrode to the
next, it goes off. This is a simple and easy arrangement, but
there is no good way to control how fast it fires or to change
that speed on the fly. Ward's design replaces the spark gap
with electronics so that the firing rate can be controlled and
the "bangs" produced sound like musical notes.
"I thought I would mention that our coils
and the coils that Arc Attack uses are Steve Ward's design,"
Larson told me. "Without Steve's work in the electronics
on these coils, I am not sure we would be doing what we are
doing at the scale that we are."
Arc Attack's Creepy Circus Song
I haven't had the pleasure of seeing Masters
of Lightning in person, but there are plenty of videos on
You Tube with their exploits. While Larson and Ward keep a safe
distance from the lightning coming off the coils, the third
member of the group jumps right in. Blake, in the persona of
Dr. Zeus, allows the giant sparks from a pair of eight-foot-high
Zeusaphones to spring to his finger tips and run all over his
The name of the character, of course, comes from
the Greek god Zeus who would throw lightning bolts at people
whenever he got in a bad mood. In order to perform this trick
you might think that Blake must possess similar god-like powers,
or at least a total disregard for his own safety. In Blake's
case it is neither. What he does have is a suit of chain mail
that makes him look a bit like a knight from days of yore. This
metal clothing is known as a Faraday suit and when it gets hit
by one of these sparks the electricity finds it much easier
to travel down through the metal mesh rather than through Blake.
This suit, making him a true iron man, allows him to do all
kinds of interesting tricks - like shooting sparks to explode
balloons filled with hydrogen in time with the music - while
keeping him relatively safe.
Arc Attack is the other group using musical
Tesla coils. The band is led by Joe DiPrima with help from Tony
Smith, John DiPrima, Andrew Mansberger and MC/ Faraday suit
stunt man Patrick 'Parsec' Brown. Arc Attack puts the
emphasis on performing their music live (Masters of Lightning
uses a computer to play theirs), but the group does use a robotic
drum kit. I don't mean an electronic drum simulator, but a real
drum set played by mechanical means and controlled by a computer.
They've also occasionally teamed up with Resonance Studio's
Craig Newswanger who owns a crazy pipe organ made out of huge
PVC plastic pipe. They use the organ, the robotic drum set and
coils to produce one of my favorite pieces, the "Creepy Circus
If you watch America's Got Talent, you
may have seen Arc Attack do their shtick. They beat out
a number of other acts to make it all the way to the semifinal
performance during season five. During one of their more recent
appearances on AGT, they introduced a guitar that can be played
to control the coils by a person in a Faraday suit while standing
in the lightning. Quite a technical feat when you consider that
the sparks would fry any normal guitar electronics and all the
equipment had to be hardened against high voltage shocks.
ArcAttack on America's Got Talent
Arc Attack has also added audience participation
to their show by building a Faraday cage. This works like the
suit but doesn't have to be sized to a particular occupant.
Volunteers stand in the cage for a song while the lightning
arcs around them. During a recent robotics championship meet
that the group played for they talked Grant Imahara, of Mythbusters
fame, into trying the cage for a number. Mr. Imahara agreed,
though he insisted on checking out the quality of the cage's
construction first. With that much electricity shooting around
him, I can't blame him.
So, between these two groups there seems to be
a bright future for musical Tesla coils. Now I'm not saying
that the Zeusaphones will become standard equipment at most
of your better symphonic orchestras. This is a pretty niche
musical market. However, the performances of both groups are
amazing and fun to watch. They sit at the intersection of science
and art, entertainment and education, and I think that's a pretty
cool street corner to be standing on.