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A Sound Education

The Birth of Home Recording

"I bought a Dutch barge and turned it into a recording studio. My plan was to go to Paris and record rolling down the Seine."
Pete Townshend, The Who

I'm conflicted on the topic of recording music at home. The business part of me frets about studios losing out on billable hours. The musician part of me relishes creating art in a non-pressure environment. But the history of artists recording radio-ready songs in their humble abodes goes back further than you might imagine. Let's explore how affordable home music recording for the masses came to be, but also look back at the origins of this revolution in recording.


11th Hour Message

1-field op

"Hostilities will cease along the whole front from 11 November at 11 o'clock."
Marshal Foch, the French commander of the Allied forces via radio atop the Eiffel Tower.

This week marks 100 years since the end of the war to end all wars, known today as World War One. In 1918, on the 11th hour, on the 11th day of the 11th month, 1,500 days of fighting came to an end. The armistice was agreed upon just six hours earlier in a railway car halfway between Paris and the Western Front. What's remarkable is the speed at which most troops were informed of the impending armistice. This war, like in so many other ways, forever changed the world of communication.

Older, established methods of communications such as semaphore, flags, signal lamps, pigeons, and dogs were used throughout the war. But electronic communications, especially radio, rapidly advanced from wagon loads of equipment to merely bulky gear by war's end. Wired telephony and telegraph were still the primary communications devices, but there were major advances in those as well.


Some inventions that sped up the miniaturization of radios included the valve (vacuum tube), amplifier, and the superheterodyne receiver (a more precise way to tune in distant frequencies). As radios grew smaller, they moved around with the troops on the ground, went to sea, and took to the air. Transmitters were placed in dirigibles and airplanes for pilots to relay back battle conditions. By the end of the war two-way communications between airplanes and the ground, and from pilot-to-pilot was possible. To give pilots freedom, and to reduce the sound of the airplane's engines, a cap with a throat microphone and earpiece was developed. This was the world's first hands-free device. To control chaos at busy military airstrips, the British developed the earliest air traffic control.

3-field ops

But most ground communications was through wires. Many, many men lost their lives running cable in battle zones. The lines were often severed during bombings, requiring deeper trenches to bury them. Ladder-type runs were also employed to ensure that if one strand were broken, the other parallel strand would carry the signal. And early on many of these signals were intercepted by the enemy through induction from the electromagnetic field. Thus, insulation was invented to shield orders from enemy ears. Enemies could also tap in to lines to pick up morse code transmissions, so the fullerphone, a quasi-encryption device, was employed. This electronically changed the way morse code signals were relayed and required special equipment on each end.


Voice transmission was quicker than morse code, but noisy lines and battle sounds tended to obscure the messages. A phonetic alphabet was perfected to aid in distinguishing letters. For instance, my name Neil would be spelled "November Echo India Lima" in the current alphabet. It changed many times over the years and varied between countries and military branches until it was standardized in 1957. That's probably good. During WWI my name would be phonetically spelled "Nan Easy Item Love." Sounds more like a proposition than military communication.


The advanced communications developments weren't enough to prevent catastrophes, however. The famous "Lost Battalion" had to rely on their last carrier pigeon to stop friendly fire on their position. Cher Ami, shot down by German troops, returned to flight and delivered the desperate message to headquarters that pleaded "For heavens sake stop it." Cher Ami would be saved by Army medics despite being shot through the breast, blinded in one eye, and losing a leg. She was awarded many honors and is on display at the Smithsonian Institution.

As with most prolonged wars, technology advances at meteoric speeds, often benefiting civilization during peace time. Some inventions and improvements that came out of WWI that trickled into everyday use include the wristwatch, the compact camera, drones, zippers, stainless steel, plastic surgery, the sun lamp, and portable x-ray machines.

A hundred years seems so far off when you think about how far technology has advanced since then. But a lot of us have a direct connection to it. My grandpa fought in the last major battle alongside 1.2 million other doughboys in the Meuse-Argonne Offensive - just a month before the armistice. He was badly injured and disabled by bullets, shrapnel, and gas. A day earlier in a nearby forest, American hero Sergeant Alvin York singlehandedly killed or captured an entire German machine gun battalion. Since this Veterans Day marks the end of World War One, let's salute the soldiers who put their lives on the line running cable, hoisting giant antennas, lugging heavy equipment into battle zones, flying in airplanes and dirigibles to radio back information, and crawling through battlefields to telegraph enemy positions. And let's not forget the pigeons, dogs, and horses that continued a long tradition of carrying battle communiques and equipment in hellish conditions.

More information on technology and communications in World War One

First World War communications and the tele-net of things.

A history of first World War technology in 11 objects

Telecommunications in war

The science of World War I communications

Northern Ireland, the first to hear of the armistice via radio from Paris

A PDF of WWI military communications from the US Marine Corps Museum

The final hours of World War I

Video on Vinyl and Other Turntable Transgressions

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"Hello from the children of Planet Earth"
From the gold records aboard the twin Voyager spacecraft

Vinyl is the format that won't die. It'll probably still be around after humans are extinct and our sun has gone supernova. Perhaps in eons, Voyager spacecraft with the golden records aboard will meet distant stars and future vinyl lovers. But in this eon, people will not stop pushing vinyl to its limits. Mad scientists and crazy artists like putting something other than music on it - or in it. More on that later.

(Drop needle onto record, scratchy gramophone sound effect)
Let's start in 1927 with Scottish inventor John Logie Baird, the first person to demonstrate television. Logie, as he probably didn't like being called, was looking for a way to record and play back video. He turned to gramophone records, the kind that Duke Ellington and Rudy Valentino were on. We think of the 1950s as being the birth of video recordings, which were on magnetic tape. But the 1920s were right in the middle of the mechanical recording age, and it only seemed natural for Baird to attempt to capture this infant technology to a mature format. Ultimately he failed to play back video, but he was successful in capturing it to disc, a process he called Phonovision. Half a century later, Donald McLean rescued the images, as well as other video-to-disc recordings from that era.
(Heralding trumpet sound)

In the mid 60s through the 70s, RCA tried to put video on discs. Making a Capacitance Electronic Disc (CED) was a very difficult process that involved cutting grooves 10 times denser than conventional LPs and coating the disc with a thin layer of metal and silicone lubricant. Each side of this fragile CED held 1 hour of video, had limited playback life, and had inferior quality to VHS. By the time of its release in 1981, VHS was winning over consumers.
(Sad trombone wah-wah-wah)

And speaking of Voyager, NASA and Dr. Carl Sagan ("Billions and billions" sound clip) crammed 115 images plus 90 minutes of voices and music onto gold-plated lacquer discs. They included a cartridge, needle, and instructions on how to play it back. One spacecraft is headed to a star called AC +79 3888, the other to Sirius. Let's hope whoever finds it has ears.
(Drum kit "bucket-of-fish")

But experimenters weren't done trying to squeeze more than grooves into grooves. Austrian artist Gebhard Sengmüller created the VinylVideo format in the 1990s, and it has been revived today by the German company Supersense. For about $225, you can buy a decoder that converts VinylVideo on a special release LP into a video signal. There are four discs available ($21), one from Motorhead, and one from the Courettes, which feature a really creepy dancing skeleton with a top hat. The video quality is...ahem...artsy at best. One reviewer recommended watching only "if you hate your eyes."
(Psycho violin stabs)

In the 1980s, a few artists and bands such as Chris Sievy, Pete Shelley, The Thompson Twins, and Shaky Stevens put software on vinyl. These were usually simple programs that contained lyrics, games, pictures, or crude video that supported the music. The idea of digital data as audio was not a new idea, as home computers used cassette decks to store and retrieve data, and phone lines carried data back and forth via modems.
(Pac-Man sound effect)

Other interesting vinyl mods over the years include pictures and holograms on the surface, hidden tracks, backwards-playing hidden messages, double-grooved sides with two programs, and clear or colored vinyl. Consumers love things that are different, and some artists have pushed the envelope to satisfy their fan base.
(Ta-da music cue)

We've talked about trying new things on the record, but what about "in" the record? Several artists have attempted, with some success, to put liquids inside the vinyl, essentially manufacturing a clear LP with a cavity under the grooves that contain injected liquid. Jack White put blue liquid in his "Sixteen Salteens" album; Worthless put red and green inside their "Greener Grass" LP; the "Friday the 13th" soundtrack album had blood-colored liquid inside; and not to be outdone, the Flaming Lips put real blood inside the "Heady Fwends" album. All of these were limited-release, and thank God only ten blood-filled albums were ever pressed.
(Evil laugh sound effect with echo)

With vinyl records selling very well to new audiences, what will some enterprising artist try next? Putting their live Instagram feed on the label? Projecting 3D holograms from the grooves? Communicating with vinyl lovers on a planet orbiting Sirius?
(Morse code sound effect, fade out)

As Seen on TV

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"Treat the recording studio as a laboratory for conceptual thinking — rather than as a mere tool."
Brian Eno

When I was young in the...cough...60s and 70s, the only real glimpses I got inside a recording studio was through television and movies. There was a smattering of documentaries and behind-the-scenes footage of studios and radio stations. I was always straining to see the control board and tape machines, or marveling at the cavernous studio on the other side of the glass. It was absolutely riveting to peek inside them and see how a record was made. The 8-foot long mixing console was often shot through a fisheye lens. Long-haired musicians were sunk down into a couch smoking cigarettes (?) and listening to their masterpiece. And there were close-up shots of that big fat 2-inch tape rolling past the heads of the recorder.


In the Moment

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"He who knows that enough is enough will always have enough."
Lao Tzu
Father of Taoism

When is enough, enough? When do you stop finessing, polishing, correcting, perfecting, or otherwise fixing something important you're working on? When you're done – either because of deadline, budget, or exhaustion – are you satisfied? Don't overkill your project.


The Elephant in the Room

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"My roommate got a pet elephant. Then it got lost. It's in the apartment somewhere."
Steven Wright

The deep seismic audio world holds many secrets, including how elephants communicate over long distances. Find out how ultra low sounds affect how a recording studio is designed and built.


Golden Ears

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“My dear girl, there are some things that just aren't done, such as drinking Dom Perignon '53 above the temperature of 38 degrees Fahrenheit. That's just as bad as listening to the Beatles without earmuffs!”
James Bond
"Goldfinger" (United Artists)

The other day, someone said to me, "You must have golden ears." He was referring to my profession as an audio engineer. He assumed that I physically had much better hearing than the average person. I don't. In fact, I often have trouble hearing conversations at loud parties and can't hear high-pitched whines that drive 20-somethings crazy. But I do think I have better hearing than a lot of other middle-aged folks only because I've protected it all these years.

So I explained to my acquaintance that I have trained myself to listen for things that the average person might not hear right away. When I mentor students about ear training, I usually start out playing a few audio clips and have them tell me everything they hear. I then make my list of things I hear, highlighting the "back" sounds - things not so obvious like rumbles, backgrounds, clicks, etc. Once I point them out, the students' eyes light up when they hear them. I tell them to listen "around" the sound, to disregard the in-your-face front sound and listen to everything else behind it.

We all have the ability to use our senses to filter out the obvious and reveal something obscure. That hidden sound, smell, or taste is usually familiar to us (but sometimes it's something completely foreign to us). If you've never had Cincinnati-style chili, that first bite will have you pondering as to why this is so different than other chilis you've had. After 2, 3, 4, maybe even 5 bites you will start to shove aside the obvious flavors like beef, tomatoes, garlic, and peppers. You'll start analyzing the spices like the chili powder, cayenne, and cumin. Then it will hit you: it's the cinnamon. Oh, and there's a little bit of clove in there. And some vinegar, too. Now you will taste those on your next bite.

When I break down a recording and listen for faults, I am usually comparing my memory of an individual sound to what I'm hearing. I know what a ground loop buzz sounds like as well as a running air conditioner. I'm familiar with mouth clicks, throat gurgles, raspy breaths, sibilance, and plosives. I've created distortion, over-modulation, hiss, crosstalk, mic bleed, comb filtering, phasing, and off-axis positioning - mostly by mistake. So when I listen around the sound, I can usually pick up on most of these if they are there. That doesn't mean I hear more than someone else, it means that I listen differently.

I'm not always listening for bad stuff by the way. I enjoy being surprised by something new, like when I hear a guitar part I've never heard before in a classic recording. Sometimes an album that's been remastered or remixed will reveal these gems, or maybe it's from just being tuned in more to the background instruments. Whatever the case, it's always fun. It's a little less thrilling to be shown the underlying part, but still satisfying. For instance, VH1's "Behind the Music" series will often isolate tracks and uncover buried accompaniments. Sometimes they will mute that track, and the song all of a sudden becomes bare without it. You heard it all along, but you didn't listen to it before.

I spent a lot of my younger days playing trombone, most of it in ensembles like marching band, wind symphonies, and jazz groups. Although I can pick out the sound of a trombone instantly, I trained myself to listen to other instruments as well. Sometimes I would need to play counterpart to the trumpets, so listening was key. But I confess that sometimes it was from being lazy. You see, there were often long periods of time in a classical piece where the brass section just sat and counted measure after measure of rests. So I trained myself to listen to what was going on just before I had to pick up my trombone, blow out the spit, and put it to my mouth. I knew that when the clarinets did that little two measure run, I was my turn.

Ear training is not easy. You may be adept at picking out one type of sound, and fail miserably at another. Being a musician, I found identifying tones easier than identifying problems like distortion. It also took me a long time to identify narrow frequencies when adjusting equalization. Knowing that the human male voice resonates between 100-300 Hz helps in grabbing the right knob to adjust. But like playing music, the ability to be able to quickly narrow that down even further takes practice.

Want to train yourself? There are plenty of paid and free ear training courses on the web. For the best success, set realistic goals for yourself. If you want to run better live sound at your church, then buckling down and learning to hear common feedback frequencies will help. If you are just interested in listening to music with an educated ear, then playing recordings of solo instruments, taking a basic music theory course, and watching documentaries on the making of classic recordings will educate you. If your ultimate goal is to work as an audio engineer, then you'll need comprehensive training.

Ear Training With Elvis

Here's some fun stuff you can do right now to limber up your ears. Let's listen to an old Elvis classic, "Little Sister." It's important to play this through good headphones or monitor speakers – phone or iPad speakers won't cut it. Click on this YouTube link and listen to the first 30 seconds or so and then come back here.

Okay, great song, great players, and of course great vocals. Let's listen again, but this time ignore Elvis's vocals and just listen to Hank Garland's electric guitar. Notice how Hank goes from single note accents to chord fills on a distinctive-sounding Fender Jazz guitar. Come back here when you're done, I'll be waiting.

If you were successful, then you just listened "around" the sound of Elvis. Now, I want you to listen to Bob Moore's bass guitar. What's noteworthy is that it's electric, and Bob Moore and a lot of other Nashville bassists usually played upright acoustic basses. Listen to the hard picking style of his bass notes and how they compliment Garland's guitar riffs. Come back when you're done.

Now let's zero in on the drums, specifically the snare drum. The song is in 4/4, that is 4 beats on the quarter note to a measure. Which beats the drummer chooses to emphasize affects the feel of the song. In "Little Sister," the snare is playing on the 2nd and 4th beats, which creates a backbeat. In rock, blues, and jazz, a backbeat can give a song a relaxed feel. In more traditional music the 1st and 3rd beats are accented, as in the Sousa march "Stars and Stripes Forever," which drives the song forward. To give "Little Sister" just a bit of interest, the beat on 2 is double. Listen to the snare doing (1)-TAP/TAP-(3)-TAP, (1)-TAP/TAP-(3)-TAP. And while you're listening to the drums, listen to the closed high-hat keeping time on all the eighth notes: 1-and-2-and-3-and-4-and. It has the effect of keeping the song from relaxing too much. Go listen and come back when you're done, I'll be tapping my foot along.

Now let's go back to the vocals. Of course Elvis nails it. With all the movement of the guitar, bass, and drums behind him, Elvis keeps his vocals smooth and almost crooning. When you're listening this time, imagine no instruments behind him. Picture Elvis singing in an empty church acapella. At about 1:35, the extraordinary Jordanaires come in with backing vocals. And listen to Ray Walker's low, low bass notes. Come back here when you're done, I'll be flipping my collar up.

Here's one last test to see if you were really listening. The Youtube video I linked to was in stereo. This helped to isolate some of the instruments for you, such as the guitar and hi-hat in the left, and the electric bass on the right. Now click on this YouTube link and listen to the mono version. Mono was the choice of the day since stereo was a new fangled thing. Try to pick out all the parts again. It's a little harder, but I've revealed them to you in our listening exercise.

Here's another great song from the same session, "(Marie's the name of) His Latest Flame." This one's in mono, so try to pick out the instruments in this one. Also pay particular attention to the luscious natural reverb under Elvis' voice.

Ear Training With Edison

Here's one more ear training exercise - but with a twist. So far we've listened to music that was recorded with great fidelity. This example has the opposite - the music is masked by poor fidelity. It's a recording on an Edison yellow paraffine cylinder from 1888. It's a choir of 4,000 voices singing Handel's "Israel in Egypt." The overriding sound of the player's mechanics may overwhelm you at first, but stick with it. You'll hear the slow, sweet harmonies of the choir start to pop out from underneath the static and thwak, thwak, thwak of the cylinder spinning. Keep in mind that at the time it was a revolutionary recording. If I were listening to it in 1888, I would probably be amazed and hear the music over the static. See what you think by listening here.

If you've successfully heard everything I've thrown at you, then congratulations! You're on your way to having golden ears. For some ear candy, I recommend picking up remastered CDs of your favorite albums. Or better yet, pick up remixed albums. If done with great care, they retain the same mix levels of the originals, but have less noise and more punch. Some of my favorites are:

  • "Sticky Fingers" by the Rolling Stones (Deluxe Edition, 2CD) on Amazon (Remastered)
  • "Beatles Anthology" 1, 2, 3 & 4 Box sets. On Amazon (Outtakes, alternates, and new material)
  • "Chicago II" Steven Wilson Remix. On Amazon (Wilson deftly remixes the entire album to make it sound "right." Pick up any Steven Wilson remix for an amazing experience)
  • "Band on the Run" Paul McCartney & Wings, 2CD, 1DVD set. On Walmart.com (Remastered, alternate versions)
  • "Ellington At Newport 1956" 2CD. On Amazon. (Remastered version that never saw the light of day until now. Original release was a studio re-creation because of bad mic placement during the live set)
  • "Smackwater Jack" by Quincy Jones. On Amazon (Remastered. Includes "Theme from Ironside" and "What's Going On?")

Listening to the Enemy

How Hollywood Hears History


"The people will waken and listen to hear
The hurrying hoof-beats of that steed,
And the midnight message of Paul Revere."
Henry Wadsworth Longfellow

What did Paul Revere's famous midnight ride from Boston to Lexington sound like in April 1775? If you were there, you might recognize the approaching horse as a Narragansett Pacer mare. This once popular breed of horse, now extinct, was known for its ambling gait: a smooth riding four-beat gait that is faster than a walk, but slower than a canter or gallop. You might also notice the calm surroundings interrupted occasionally by crow calls, trees rustling in the wind, or the occasional farm dog barking at the stranger barreling down the rough dirt road. Just someone in a hurry.

I wonder how Henry Wadsworth Longfellow heard it in his head in 1860? Longfellow brought the nearly obscure ride by Revere into the public consciousness with his poem "Paul Revere's Ride." For impact, he glorified the ride with creative license and literary tools to warn that our country was about to fall apart (it did with the Civil War). I would think that those hoofbeats were probably a bit louder and more urgent in his mind.

What about you? Now that you know the significance of that ride, can you hear the thundering hoofbeats, the snorting horse, the jingling bridle, and Revere snapping his reins and kicking his heels into the giant beast's sides? Maybe Tim Burton or JJ Abrams has influenced your imagination. We've been conditioned by Hollywood to "hear" history differently from what it probably really sounded like. Guiding the listener is the cornerstone of sound design, so a movie about the famous ride might have those hoofbeats sound more explosive than truthful. In the end, it may be worthwhile if we simultaneously entertain and bring light to Revere's contributions to the Revolution.

Liz Covart, host of the podcast "Ben Franklin’s World" and Digital Projects Editor at the Omohundro Institute of Early American History and Culture in Williamsburg, VA wondered in a blog post: how authentic should sound designers be with history? She points out that our environment is much different than it was 250 years ago. We have paved roads, differently constructed buildings, powered transportation, industry, and many more people. With the majority of Americans living in urban areas today (6% in 1800, 80% in 2018), our perception of a quiet night is quite different than Paul Revere's. We modern Americans also have a collective naïveté of what a galloping steed on a dirt road would really sound like because we have replaced horses with horseless carriages.

If there's one thing I've learned about sound design, it's that real sounds of life sound really lifeless. Like Liz Covert, I would also ponder accuracy while telling Paul Revere's story with sound. Do I record a pacer's ambling gate on a deserted country road? Hopefully I could find someplace free of airplanes, cars, machinery, and other people. (I wrote about the rarity of quiet places in one of my A Sound Education articles). Or maybe I take the Hollywood route and have the ride sound larger than life? I think it depends on the audience. If it's a room full of scholars who delight in historical accuracy, then go with the pacer. If it's a cinema full of families with popcorn and Jujubes, then go with the thunder. Or maybe a pacer mixed with thunder...but let's not overthink this.

Speaking of horses, here's a real-world example of blending authenticity with impact. I worked for several years on the crew for the Triple Crown Radio Network. We broadcast the three legs of the Triple Crown (Kentucky Derby, Preakness Stakes, and Belmont Stakes), and the Breeder's Cup races. One of our challenges was how to add excitement to the sound of the race. We had to do much experimentation within boundaries and rules to find the right sounds of each race. For instance, we were not allowed to mount a wireless mic on a horse of jockey to catch the sounds of riding. We were also limited to how many mics we could use trackside to capture hoofbeats. We tried a parabolic mic (those big dish-looking contraptions on the sidelines of a football game), but the sound was thin and the track too large for complete coverage. What we ended up doing – and this is like finding out how a magic trick is done – was to pre-record hoofbeats at each track under a variety of conditions, and then blend those into the mix.

We were very keen on keeping the race sounding as organic as we could. We installed several supercardioid shotgun microphones along the stretch run of each track and recorded races over several days. We would then layer a few of these and create an endless audio loop for that particular race track. We were also very careful to have different loops for different track conditions, so if it was raining and sloppy, we had that distinctive sound for that racetrack. When the race began, our mix engineer would subtly blend in the looped sound underneath live microphones we already had installed around the track. As the horses came down the stretch to the finish line, he would fade out the loop and fade in the trackside boom microphones for the authentic live sounds of hoofbeats, whips, and jockey shouts. This was the sound of real live thundering hooves making history.

Ghost Whispers


"I have been at work for some time building an apparatus to see if it is possible for personalities which have left this earth to communicate with us."

Thomas Edison, 1920

What if you nonchalantly recorded something around your house, let's say a music practice session. Then when you played it back, you clearly hear someone whispering. You didn't hear it when you recorded it, so what was it? Many unfamiliar sounds throughout history can be attributed to nature, machinery, and even hoaxes. As our post-industrial society grows, so does the list of unexplained sounds, like trumpet sounds from the sky, humming cities, and ocean whistles. The proliferation of audio and video technology has generated its own tally of the strange. Specifically, weird voices that have been inadvertently and unknowingly captured. These recordings and transmissions sound eerie but have a very unsexy-sounding name: "Electronic Voice Phenomenon," or EVP.


We're Fifteen!

Neil at 12 playing DJ

"I will never be an old man. To me, old age is always 15 years older than I am."

Francis Bacon

Dynamix turns fifteen years old this month. Well technically sixteen, because I incorporated a year earlier and did small jobs out of my basement until I could step out on my own. When I did, I couldn't have timed it better. As I wrote about in our ten-year anniversary newsletter, the Great Ice Storm of 2003 delayed our opening for a week. In fact, I was stuck in Dayton, Ohio for several of those days.


A Myth-terious Thing

2015-March Myth-terious

"Any sufficiently advanced technology is indistinguishable from magic."

Arthur C. Clarke

To the average person, audio can be a mysterious "myth-terious" thing. Many people don't want to admit that they are intimidated by the technical side of it, and that makes sense. The closest most people get to manipulating audio is adjusting the volume on their stereo. I bust 10 common myths about recording audio.


The Shadow Knows


Shadow: No, Mary. I suspected a trap, so after I opened the door, I walked across the room and stood behind them.
Apple Mary: But your voice.... it came from near the door.
Shadow: Ventriloquism. A simple trick of projecting the voice.

The Shadow
"The Blind Beggar Dies"
Radio broadcast: April 17, 1938

We're fooled by Mother Nature all the time. She uses light to conjure up a mirage on a hot desert day and Aurora Borealis on a cold Alaskan night. She also has a bag of tricks for sound, like flinging noises a hundred miles away. But one of her best is when she makes sound disappear. This slight-of-hand by Mother Nature may have even changed the outcome of several battles in the American Civil War. What are these shenanigans of sound? Magic? Illusions? Sorcery? As the old radio serial hero said, "Only The Shadow knows." They're called acoustic shadows.