[Wilhelm scream] Have you ever wondered how those sounds became associated with horror films?

Sounds are critical to most films.

They can help establish a scene's mood, provide insight into characters, and alert the viewer to important information.

So, there are two major camps of film soundscapes.

Sounds that the audience can hear but the characters on screen cannot are considered "non-diegetic."

They can be used to signal impending danger, like background music.

"Diegetic" sounds are ones that the characters on screen can hear and react to, like someone screaming.

This particular music is made by a theremin, an electronic musical instrument played without being touched.

The box has a vertical antenna on its top and a metal loop on the side.

The musician controls the pitch by varying the distance of one hand from the antenna and controls the volume by moving the other hand around the metal loop.

The theremin then amplifies these electric signals and sends them to a loudspeaker.

It has a particularly otherworldly vibe.

In 1967, the music critic Harold C. Schonberg poetically described the sound made by the theremin as "not unlike an eerie, throbbing voice," or "a cello lost in a dense fog and crying because it does not know how to get home," which is weirdly tender to talk about the theremin, but whatever.

But despite the touching and tender sentiments that it evoked in music critics, you may be surprised to learn that the theremin was developed as part of a Soviet research program in the 1920s by a man who lived a life of art, espionage, and forced exile from his adopted home.

Theremin music often crops up as the non-diegetic backdrop of our favorite horror classics.

On the other hand is the diegetic movie trope, more popularly known as the Wilhelm scream, a stock sound-effect first recorded in the 1950s and used hundreds of times since, sometimes in action-packed scenes and other times to underscore onscreen horror that would make your blood curdle.

But who the heck was Wilhelm?

Why was he screaming?

And why have sound engineers used the same exact scream over and over in hundreds, if not thousands, of projects?

So, today we're diving headfirst into the sounds that make us scream to figure out why these two sounds started cropping up in so many of our favorite films.

[spooky music] So, first, a little bit of rundown on the theremin.

In 1920, a young Russian physicist named Lev Sergeyevich Termen was researching proximity sensors in the Physicotechnical Institute in Petrograd.

Proximity sensors are used to detect the presence of a nearby object without physical contact.

They work by emitting electromagnetic fields, or a beam of electromagnetic radiation, and then tracking changes in the field or in the return signal.

Proximity sensors can be used in a variety of applications, including in weapon systems.

At the time that Termen was working, Russia was embroiled in a civil war.

In this conflict, Vladimir Lenin's Red Army was defending his Bolshevik government against other Russian factions.

Lenin had an urgent need for weapons.

While researching proximity sensors for Lenin, Termen discovered that they could also be used to produce unique sounds.

He designed an etherphone, which isn't a telephone covered in ether that knocks you out when you pick it up, but rather a box that contains vacuum tubes that produce two sound wave frequencies that oscillate above the range of hearing.

When positioned near one another, these tubes create an audible frequency that reflect the differences in the tubes' rates of vibration.

By moving one's hand near the box, it was possible to alter these frequencies and make different sounds.

In 1922, Termen demonstrated the instrument for Lenin at the Kremlin.

In the West, Termen became known as Leon Theremin.

In 1925, he traveled to Germany to sell the patent for the instrument that the Germans dubbed the "theremin vox" to a manufacturing firm.

According to his biographer, Albert Glinsky, the trip had two purposes.

One was to make money off the sale.

The other was to open a back door to Western technology.

Theremin toured other European countries demonstrating his instrument and gathering information.

In the late 1920s, he and his Russian wife, Katia, moved to New York, where Theremin set up the Theremin Laboratory, patented his instrument, and performed at Carnegie Hall.

Soon after, he sold the commercial production rights to the theremin vox to RCA, which started producing it in 1929.

However, was there more to Theremin's stay in New York than meets the eye?

It is established that Theremin had designed tools for Lenin and also worked as a corporate spy on his behalf.

Why then do some accounts suggest that Theremin was taken from his New York apartment by NKVD agents, a group that would later become the KGB?

Theremin's biographer Glinsky suggests that Theremin may have fled the U.S. to escape personal debts, yet his reception at home was also pretty chilly.

According to the "New York Times," Theremin was convicted of anti-Soviet propaganda and sentenced to seven years of prison in Siberia, which is about as chilly as a reception gets.

He was later moved to a prison in Tomsk.

Here he developed remote-control planes and methods of tracking ships behind enemy lines.

He also invented a small electronic eavesdropping device.

In 1945, one of these bugs was embedded into a replica of the Great Seal of the United States that a group of Soviet children presented as a gift of friendship to the U.S.

Ambassador to the Soviet Union.

"The thing," as this would later be called, transmitted information from the embassy to the KGB for six years.

As a reward for his contributions to Cold War espionage, the government released Theremin from prison and granted him the Stalin Prize... in secret, of course.

According to Glinsky, many in the West assumed that Theremin had died near the end of the Second World War.

However, he continued to work for the KGB until 1966.

But during the period that he was away from the United States, the theremin became a niche instrument.

In the 1950s, Robert Moog began building theremins as a hobby.

Later, he mass-produced theremin building kits.

Moog claims that tinkering with these kits helped him develop the Moog analog synthesizer, a device that altered the sound of many late 20th-century works of music.

The music has cropped up in the work of a wide range of classical musicians who use it in their performances, but it's probably more famously known for its appearances in popular films.

Although it's hard to pin down the first date the theremin appeared, most of its earliest appearances in film are in soundtracks that require an eerie, otherworldly vibe.

The composer Miklos Rozsa used the instrument in film scoring in 1945 when he wrote the score for "The Lost Weekend," and he won the Academy Award using it in the score for Alfred Hitchcock's suspenseful "Spellbound."

In 1947, Rozsa used it to score the film "The Red House."

And in 1951, Bernard Herrmann followed suit and used the theremin in his score for "The Day the Earth Stood Still."

More recently, it's been used in the soundtracks for "Ed Wood," "The Machinist," "Monster House," and "First Man."

So, the next time that you hear this... [theremin plays] you can think of Cold War espionage and the fascinating life of the man who made the sound possible.

[Wilhelm scream] Has someone been shot?

Is a Stormtrooper falling from a ledge?

Is an alien flying into space after an explosion?

Not today.

I'm simply pushing a button that plays the Wilhelm scream, a stock sound effect from the Warner Brothers library.

Much as theremin music contributes to the viewer's experience of a movie scene, this particular scream resonates with a viewer on two levels.

This scream seems to be a diegetic sound-- that is to say, a sound that one character makes and that other characters in the movie might hear, but it's actually a stock sound effect that's added to the film after production.

For those in the know, the familiar sound of the Wilhelm scream draws attention to the constructed nature or fakeness of the violence being presented visually.

Its effect can be to ironize the violence and perhaps even to alter its significance.

And here's PBS's resident monster expert, Dr. Emily Zarka from "Monstrum," to tell us a little more about it.

The Wilhelm scream is named after Private Wilhelm, a character in the 1953 Western movie, "The Charge at Feather River," who had the rather unfortunate fate of being shot in the thigh by an arrow.

As Sean Hutchinson has reported in "Mental Floss," a group of sound designers at U.S.C's film school during the 1970s observed that this scream had been used in many films and named it after this character.

However, the sound effect had in fact been used earlier, in the 1951 film, "Distant Drums," as a soldier walking through a swamp in the Everglades is attacked by an alligator and dragged underwater, and again in the 1952 film, "Springfield Rifle," as a raider is stabbed with a sword.

The scream is widely thought to have been made by the actor/ musician, Sheb Wooley, who had been a voice extra on "Distant Drums," and who, in 1958, would later gain fame for recording the popular song, "Purple People Eater."

The U.S.C film school students began adding the effect into the films that they were making as a sort of in-joke.

One of the students, Ben Burtt, went on to design the sound on George Lucas's "Star Wars."

Burtt used the sound effect after Luke Skywalker shoots a Stormtrooper, who screams as he falls from a ledge in the Death Star.

Burtt would later incorporate the scream into other films in the "Star Wars" series.

Several film enthusiasts have painstakingly compiled these scenes in online videos.

In February 2018, Matthew Wood, supervising sound editor for Skywalker Sound, announced that the studio was going to move away from using the Wilhelm scream in "Star Wars" films and has already started using a new scream that he dubs, "our own little calling card."

Keep your ears open for these.

Thanks, Emily.

But even though "Star Wars" gave Wilhelm a sonic facelift, the old Wilhelm scream is still peppered throughout our favorite films.

It's even cropped up in scenes that are lighter on the horror and action side, showing these hollering pipes really do have the range.

Ben Burtt won special achievement and best sound effects editing Academy Awards for his work on the "Indiana Jones" series.

In one scene, he uses the scream as a crocodile eats a man, making a subtle gesture towards the film "Distant Drums."

Other notable films that also use the scream are "Lord of the Rings," "Reservoir Dogs," "Kill Bill: Volume One," "Inglourious Basterds," "Toy Story," and "Avatar," just to name a few.

A website called tvtropes.org has compiled an extensive list of uses of the scream in anime, animated and live-action films, literary references, television shows, music, pinball games, video games, and web animation.

Check it out if you have some free time, or a lot of free time, because it's a long list.

It's a real "scream."

I'm sorry, but you had to know that I was gonna do that somewhere in here.