Within an anechoic chamber, all surfaces are covered with specialized materials that prevent wave reflection, helping prevent sound from echoing in the space.

Stonehenge may have functioned as an echo chamber designed to keep ceremonies secret from outsiders.

Acoustics researcher Trevor Cox discovered that Stonehenge acts like a concert hall, reflecting and amplifying sound. This video shows Cox demonstrating the effect using a scale model inside a soundproof studio.

Interacting sound waves can create regions where the pressure from each wave combines, allowing objects to levitate in place against gravity or be manipulated for touch-free construction.

Faraday cages protect enclosed objects by redirecting electrical currents

Constructed from conductive materials, the cage allows electrons to distribute themselves evenly throughout its surface and travel to ground, keeping the interior neutrally charged and preventing any internal electricity. The same principle blocks electromagnetic waves by redirecting the electric field component, preventing telecommunication signals from entering the apparatus.

People with tinnitus should avoid silence—sound-rich environments distract the brain

This podcast from an audiologist discusses common questions about tinnitus. It notes that tinnitus could be described as a phantom sound associated with hyperactivity in the brain. It's linked with loud sound exposures above 85 decibels, hearing loss associated with aging and stress, among other factors.

Ultrasound machines emit and receive high-frequency sound waves to construct images of the body's interior, with differences in the penetrating power of different frequencies allowing medical professionals to identify different structures.

Listen to the 'sounds' of the universe with this sonification library, where astronomers have transformed certain astronomical data sets into audio for broader engagement.

View a collection of sound animations, which depict how a source of sound waves pushes against particles to carry energy away without matter being displaced.

The three smallest bones in the human body—the malleus, incus, and stapes—amplify the vibrations of sound waves by almost 20 times to help enable hearing.

Drum shields—barriers that drummers are often seen playing behind—help prevent drums from being picked up by other onstage microphones, thereby improving audio mix quality.

We hear because soundwaves are converted into electrochemical signals in our ears

This science teacher video systematically walks through the biology of the outer, middle, and inner ear. The explanation starts with the auricle, an external part that funnels sound through the auditory canal, and the tympanic membrane (the ear drum), which vibrates when sounds hit it. Beyond that, as the video details, is the eustachian tube, which is connected to the back of our throats and allows air to pass in and out to equalize ear pressure.

Studying 'sonic' black holes

If a fish screams as it falls down a cascading waterfall accelerating to ridiculous speeds, will his fish friends above hear him scream? This analogy, odd as it is, has become an essential tool in the astrophysicists kit for learning how enigmatic black holes operate. Lab experiments mirroring the so-called sonic black hole have achieved insights for their cosmic counterparts. Read how it works in this brief piece.

Noise-canceling headphones use a microphone to identify external sounds, which are then used to produce an out-of-sync version of those sounds to cancel them in your ears.

In television and film, certain sounds, such as dialogue, may be difficult to understand due to sound mixing, device limitations, and technological advancements that have collectively reduced clarity.

How does the cocktail party effect work?

In the 1950s, British cognitive scientist Colin Cherry started to explore how we could focus our hearing on one single source, even in a noisy environment. This video animation explains the phenomenon known as the cocktail effect and how selective hearing works. Discover how our brain is on the lookout for important or personally relevant information, even as we are occupied in other discussions.

A person's voice sounds different when breathing helium, sulfur hexafluoride, or gases other than air because the speed of sound varies with the properties of the material through which it travels.

Acoustic Vehicle Alerting Systems provide motor sounds in electric vehicles

Since 2019, various global standards have set requirements for these systems, which seek to mimic combustion-engine sounds by meeting specific sonic criteria, including sound pressure, frequency, and pitch. Sound engineers design these systems to meet these requirements, ensuring that passers-by, particularly the blind and visually impaired, can detect the presence of a vehicle.

Sonar, or sound navigation and ranging, uses reflected sound waves to map and detect seafloor features, marine organisms, and other obstacles.

If a source of music traveled past someone at twice the speed of sound, assuming sufficiently sensitive hearing and powerful equipment, they would hear the music backward.

An ear doctor with hearing loss seeks to help those with hearing loss enjoy music

Alex Chern, an ear doctor who has hearing loss himself, dreams of restoring the ability to experience "all the richness and the beauty of the sound of music" for patients—not just functional hearing. Hearing aids amplify sound waves and aren't designed to work well with music that may have varied pitch and volume. Chern is studying how hearing loss and engaging with music may affect cognitive decline.

Objects can be made invisible through refraction, in which light from behind an object is bent around it, making only the background visible.

High-frequency sound waves have been used to brew espresso with room-temperature water and about one-fourth the energy of a traditional espresso machine, which relies on hot water and pressure.

The mass of a cell can be measured using hollow, vibrating beams

In 2010, scientists at MIT constructed a U-shaped device that vibrates like a guitar string with an internal fluid channel. As cells and bacteria pass through the device, its rate of vibration shifts, with greater mass creating larger shifts.

See what loud noises do to inner ear hair cells

This animation illustrates how louder music can affect inner ear hair cells. Damage to these cells is generally considered permanent. Hearing protection like ear plugs can reduce the level of sound entering into the ear and help protect those cells.

When struck, objects vibrate at unique rates called resonant frequencies, which makes tapping wood sound different from tapping metal, but providing objects with sound at their resonant frequency can cause them to shatter.

Objects that move faster than the speed of sound—Mach 1—create shockwaves called sonic booms by building up and forcing sound waves to combine as they lag behind the object.

Ambient sounds on Mars are lower-pitched and more muted than those on Earth

The planet's thin atmosphere absorbs higher frequencies, and audio captured by the Perseverance rover from the Ingenuity Mars helicopter revealed that sound waves travel farther than previous atmospheric models suggested.

Scientific applications of bubbles include logic gates, laser production, and medical imaging

Microbubbles of nonreactive gas can be administered to improve the reflection of sound waves and the resulting imaging during an ultrasound. Bouncing light waves within a bubble can stimulate emission of light from a trapped chemical, just as occurs within a laser, and bubbles can act as valves that control the flow and reaction rates in microfluidic systems.

If hearing is damaged, the brain may amplify remaining sounds, perhaps causing tinnitus.

Some animals possess sensitive hearing to help pinpoint prey and map the world

Bats and dolphins produce sound to reflect off surfaces and create a mental image of their surroundings. Owls' faces are dish-shaped to help funnel sounds to their ears, including that of mice moving along leaves or snow. Pinnipeds, such as seals and walruses, hear in both air and water.

Fish populations in the Great Barrier Reef have increased after installing waterproof speakers on the ocean floor that played recordings of sounds from healthy coral reefs.

Listen to the pair of colliding black holes detected by LIGO

As ripples in spacetime, gravitational waves do not produce sound, which is the perception of specific vibrations in matter (e.g., vocal cords vibrating air molecules). The "chirp" of gravitational waves comes instead from converting the spacetime ripples into sound waves that the human ear can hear.

What (and why) is ASMR?

ASMR podcasts and videos are appearing all over social media, so what exactly is it, and what does it do? This immersive article explains the phenomena of ASMR, which stands for autonomous sensory meridian response. ASMR is when certain sounds or...

Phil Spector's 'wall of sound' revolutionized girl groups—and pop music

The method captured a room of live musicians and transmitted the sound into a basement outfitted with more speakers and microphones. That sound was then sent into the central control room, producing a massive recording that sounded unlike anything else in pop music.

Audi spent over three years developing engine sounds for its electric vehicles

Unlike the sounds made by combustion engines in gas-powered vehicles, electric cars produce no motor sounds. The company's acoustics team worked with composer Rudolf Helpmier to craft an electric-inspired revving sound for its R8 e-tron supercar.

Watch how the machine at the heart of NASA's Cold Atom Lab produces atoms near absolute zero—the coldest theoretical temperature in the universe—for experiments involving quantum phenomena.

What Stonehenge sounded like

Researchers built the first scale model of the world's best-known prehistoric stone circle, Stonehenge, to study its acoustic properties. Built approximately 5,000 years ago, the landmark in southern England has puzzled historians for centuries, but...

Despite the name, infinity mirrors—mirrors that reflect each other—do not produce reflections to infinity because mirrors absorb some of the incoming light with each reflection.

In 1925, the Isolator was a helmet designed to combat procrastination and improve concentration by narrowing a person's field of vision, blocking environmental sounds, and providing oxygen.

Audism is institutionalized discrimination against deaf people

Promoting the idea of hearing-at-all-costs in medical and education settings has created division in the deaf community and influenced decisions about learning sign language.

The Grateful Dead pioneered a massive 3-story, 75-ton, 600-speaker sound system that revolutionized live audio in the early 1970s.

Scientists are learning to guide your dreams using sound and touch.

Learn how to build your own cloud chamber to detect cosmic rays—particles from space that move near the speed of light—at home.

Even in a perfect vacuum, empty space is full of quantum activity

Scientists have tried to create “nothing” by removing all matter, energy, and heat from a container, but the uncertainty principle and relativity prevent such conditions within any period of time. This means the universe is full of quantum foam, which can produce forces from nothingness.

Explore a visual and auditory guide to wave properties and waveforms to learn how every sound imaginable can be created by combining multiple vibrations of air.

Some sounds that have been shown to affect mood and noise have been given color names, such as brown, pink, and green noise, corresponding their frequencies to those of light.

In LIGO's interferometers, light cancels itself out in the absence of gravitational waves

The devices are designed so that a laser is split into two beams that later recombine, canceling each other out and producing no signal. Changes in the lengths of the arms due to passing gravitational waves result in an interference pattern whose properties reveal features of the objects that created the waves.

By igniting flammable gas in a tube filled with holes and playing music into it, the fire will take the shape of the sound waves, enabling the visualization of audio.

Why Edwin Armstrong developed FM radio

AM radio was popular but prone to interference and static, which could be frustrating for listeners. In 1933, Armstrong, a Columbia University professor, discovered that a clearer signal could be broadcast by revising how it was captured.

Notch music therapy may filter out some tinnitus frequencies

Researchers in Germany have developed a smartphone app-based therapy for individuals with tinnitus associated with hearing loss. Some people with tinnitus can use this Notch app with their hearing aids to at least partially block sound frequencies matching their tinnitus pitch—turning down the volume of their tinnitus.

An expert recreates the voice of a 3,000-year-old mummy

Ear, nose, and throat expert David Howard discusses how his research team extracts vocal folds from preserved human tissue, which allows them to model the deceased person's larynx. From there, they can create a synthetic voice based on the organ's geometry.