During the day, when ambient noise tends to be at its peak, the brain filters familiar sounds to background hum: The same creaking hinge that goes unnoticed at noon may cause alarm at night. Ackerman explores auditory illusions, including the phantom voices heard by both religious mystics and people with schizoaffective disorders. She describes the rare phenomenon of musical epilepsy, likely a result of stroke affecting the brain’s temporal lobes, causing songs to play relentlessly in the patient’s mind.

Ackerman considers it remarkable that humans can selectively amplify some sounds while diminishing others—for example, focusing on one conversation amid the clamor of a crowded room. This ability arises from the structure of the ear: The outer ear directs sound into the inner ear with minute delays that the brain uses to locate the sound’s source. Ackerman closes with a personal anecdote about a selectively ignored sound: Disturbed by the sound of a cat eviscerating a mouse, she focused on ice water dripping onto hay, creating an “emotional curtain.”

Speech begins with air expelled from the lungs, which vibrates vocal cords in the larynx. Language records history. The Norman conquest of 1066 imposed French as the language of “polite” society in England, making words “perspiration” and “fornicate” polite while their Anglo-Saxon equivalents, such as “sweat” and “fuck,” became crude. Some legal documents began to include both Saxon and French, a habit that persists in seemingly redundant legal phrases like “keep and maintain.”

Onomatopoeia mimics sounds (“hiss,” “murmur”). Dialects and local accents make it possible to identify a person’s background by the way they speak. The range of sounds that enables human speech, unique among mammals, arises from our low-lying larynx, an evolutionary adaptation that comes with significant tradeoffs: Unlike other mammals, humans cannot swallow and breathe at the same time, and we are much more susceptible to choking. Given such tradeoffs, Ackerman surmises that the development of speech must have carried great evolutionary advantages.

Ackerman recalls the physically painful experience of listening to loud music on campus when she worked as a college professor. For teenagers, loudness itself provides an erotic thrill, though it can lead to premature hearing loss. Researchers have photographed cochlear hair cells destroyed by a single loud encounter.

In the 1970s, psychologist Arlene Bronzaft performed a study in a Manhattan grade school in which the reading skills of children in classrooms facing elevated train tracks fell 11 months behind those of their peers on the quieter side of the building. The deficit disappeared after noise-abatement. “Noise” technically contains all frequencies but colloquially means unwanted sound. Neurologists theorize that fingernails on a chalkboard provoke revulsion as a relic mimicking a shriek of terror or predator claws.

Peak human hearing spans 16 to 20,000 cycles per second, narrowing with age. Humans’ inability to hear very low frequencies may be adaptive, as it spares us what would otherwise be the constant distraction of our own body’s sounds. Stethoscopes and radio telescopes extend our reach. Bats and dolphins use echolocation, replicated in ultrasound and sonar.

Medical monitors translate heart rhythms to beeps, and some researchers have proposed using melodies to represent subtler information. At Intersonics Inc., scientists use “acoustical levitation”—intersecting ultrasound beams—to suspend objects for contamination-free manufacturing of glasses, alloys, and superconductors on Earth and in space. Sound is a potent physical force.

The composer John Cage, whose composition 4’33” famously comprises 4 minutes and 33 seconds of silence, said true silence is impossible—even in a completely soundproof environment, one hears internal body sounds. Deafness isn’t the absence of sound; many legally deaf people hear loud noises. Since semicircular canals in the inner ear regulate balance, some deaf people face equilibrium problems.

Helen Keller considered deafness worse than blindness, cutting one off from the human voice that stimulates thought. Literary tradition includes Mark Medoff’s Children of a Lesser God and Paul West’s Words for a Deaf Daughter. Poet David Wright’s autobiography describes his world as seldom appearing silent—the brain translates visual movement into “eye-music,” so a rustling leaf creates the illusion of sound.

Ackerman looks beyond human experience to consider how other animals interact with sound. Birds of the same species sing in different “dialects” in different regions. Dogs can distinguish the sound of their owner’s car engine from those of other cars; owls use their asymmetric ears to pinpoint the source of a sound with far greater precision than humans can achieve. Animals occupy different “auditory niches,” hearing best at different frequencies. In this way, prey animals hide their warning sounds from predators, and all animals avoid being overwhelmed by the din of their environment. 

Hearing can involve other parts of the body, not only the ears. Fish sense vibrations in the water; some frogs and lizards hear through lungs; dolphins may receive sound through oil-filled jaws. Hearing and sound also have uses that go beyond communication. Sperm whales may use sound to stun prey. Bats echolocate via high-frequency clicks, mapping their surroundings. Elephants and alligators use infrasound. Male alligator “water dances” combine visual spectacle with infrasonic signal. The natural world, including the ocean, is alive with sound.

Sound travels much farther through water than through air. Male humpback whale songs, first recorded off Bermuda by Frank Watlington and later by Roger Payne, last about 15 minutes and repeat for hours, structured in themes. The songs evolve yearly—whales arrive singing last season’s song, and then collectively learn new phrases. It is thought that they produce sound “by moving air around inside their heads” (200). Divers feel the soundwave of a whale song like a drum pounding the chest. These sounds striking ancient wooden hulls likely inspired the Greek myth of the Sirens.

Musical instruments existed in Mesopotamia 5,500 years ago. Ackerman recalls her fascination with Stradivarius violins as a young violin student.

Cambridge University researchers discovered a thin layer of pozzolana—volcanic ash from Cremona, Italy—between the wood and varnish of a Stradivarius cello, likely a strengthening agent whose acoustic effects Stradivari didn’t know. In a more poetic theory, violinists believe instruments “remember” music, with the vibrations produced by previous players microscopically altering the wood. A master’s duty is educating the instrument for future generations.

Music has direct physical impact. Singing produces vibrations in skull and sternum—an “internal massage.” Chanting mantras creates “inner white noise” aiding meditation.

Music is a non-rational language for feelings. The Shaker hymn “Simple Gifts” has plain words but a “catchy” melody inspiring joy. Hymns climb from low to high notes for spiritual uplift; a sudden drop enacts a “swoon” of desire. Complex classical pieces mirror emotional arcs. Mozart and Wagner described work in emotional terms. Music bypasses the imprecision of words, placing unnamable emotion directly in the listener.

A Harvard psychologist argues that music is a distinct intelligence in the right frontal brain. Musical capacity is hereditary—infants respond—but tastes are learned. Generations define themselves against their parents’ music; waltz, swing, and tango were initially dismissed as noise or villainized as scandalously sensual.

Music relies on mathematical intervals, and the study of music as math dates back at least to the ancient Greek mathematician Pythagoras. In recent years, some scientists have proposed using music as a universal language to communicate with possible extraterrestrial intelligences. Composer George Rochberg argues that music isn’t just math; its logic ties to the central nervous system—or, in other words, “we listen with our bodies” (212). Language and music are organized sounds from primal cries. Words are rational sounds for objects; music is non-rational, a “controlled outcry” for feelings, understood instinctively across cultures.

Ackerman quotes the 18th-century English playwright William Congreve’s famous claim, “Music hath charms to soothe a savage breast” (216)—that is, music calms human emotions. Physiological psychologist Manfred Klein found Japanese businessmen and Indigenous Australians had identical muscle responses to Bach passages, matching patterns for joy and anger.

Music therapy reaches comatose patients, helps handicapped children, encourages exercise, relaxes angina patients, and helps cancer patients and the elderly. Pleasure links to the brain’s “river of reward,” identified by chemist James Olds in rats. At Stanford, when listeners experiencing “chills” received naloxone (blocking endorphins), rapture vanished—proving a link between music and brain chemistry.

Western music evolved from single-melody forms to multivoiced. Early religious music like Gregorian chant was homophonic. Polyphony—combining tones into harmonic chords—was a revolution that arrived during the Middle Ages. Unlike blending colors, tones occupy the same “space” while remaining distinct.

Music’s evolution parallels that of architecture. A Romanesque church’s simple interior suited Gregorian reverberations; a Gothic cathedral’s complex space would fragment such chant. Most Western music marks time with regular beats, though early forms were unmeasured. Genius lies in the tension that arises as composers seek creative freedom within highly structured forms, such as the sonata. Philosopher Victor Zuckerkandl marvels that music, comprised of “nothing but tones” (221), became so deeply significant.

Music is inherent in nature. Thai Buddhist monks record electrical phenomena from Earth—rocks, trees, soil—translating patterns into compositions, believing they hear Earth sing. American composer Charles Dodge created electronic music from sun-Earth magnetic field data. Recordings capture Jupiter’s magnetic field in the form of music, with pulsars (stars that appear to pulsate rhythmically when viewed from Earth) used as percussion.

Earth makes audible sounds. In Moodus, Connecticut, shallow earthquakes create “Moodus noises,” leading the Indigenous Wangunk people to call this area “the place of noises,” attributing the sounds to an angry god. San Francisco’s Exploratorium has a pipe organ played by harbor tides. The universal human instinct creates music from elements through flutes and pipes—breathing spirit into nature, giving it a voice.