Ralph Stanley, in 2011. Photograph by Ed Rode / AP

The bluegrass musician Ralph Stanley, who died Thursday evening, at the age of eighty-nine, leaves behind an enormously influential—and just plain enormous—body of work. As one half of the Stanley Brothers, a band on the short list of bluegrass originators, he recorded more than three hundred songs over two decades, ending in 1966. In the fifty years after that, working as a solo act in a style he was careful to identify not as bluegrass but as the old-time music that folks today call bluegrass, he recorded about a thousand more songs, spread across some seventy-five albums. That’s all good news.

The bad news is that, when it comes to Ralph Stanley’s voice, there has only ever been the one, and there will be no replacements. Stanley’s voice has been called “a force of nature,” “otherworldly,” “elemental,” “eerie.” Try to describe it and you inevitably tumble into a deep mountain mine of contradictory clichés. Trying to capture its singular tone in a fresh way risks foolishness. (“Like a woodwind crossed with a coonhound, turned up to eleven” is a note I just jotted down, before scratching it out.)

His voice sounded so vital and powerful, and yet at the same time so frail and so very, very old. Stanley recalled more than once that, as a child, he was known in his Primitive Baptist Church community as “the boy with the hundred-year-old voice.” There is a danger, though, in focussing on the strangeness of Stanley’s voice. As with his rendition of “O Death,” the folk song he sang a cappella for the Coen brothers’ 2000 film “O Brother, Where Art Thou?,” the supposed weirdness of a Stanley vocal performance is easily mistaken for the essence of his art. That something as universal as a man praying for safe passage to another year was deemed exotic and haunting by contemporary audiences, rather than as ordinary and human, says more about us, I think, than it does about Ralph Stanley.

Stanley was born in 1927 in the Clinch Mountains of Dickenson County, Virginia. In his as-told-to autobiography, “Man of Constant Sorrow,” named for the song he continued to consider his signature number even after “O Death” earned him a Grammy, Stanley presents himself as “a backwards kid who could scarcely hand over a howdy,” who was asthmatic and worried about everything—especially the prospect of a life spent working in the coal mines that dominated the region. He learned to sing at church, and his mother taught him how to play the banjo, clawhammer-style.

Music provided Stanley an alternative to working at a sawmill, like his father, or in the mines, as his stepbrothers did. For Ralph and his brother Carter, a year and a half older and gregarious and jocular where Ralph was anxious and tight-lipped, music wasn’t a path out of the hills; it was a safer and less soul-robbing way of staying put in the place they loved. In honor of that place, Ralph and Carter named their band the Clinch Mountain Boys.

They began their career in 1946, not long after Ralph returned home from serving in occupied Germany. One of Carter’s early songs, “The Little Glass of Wine,” popular on the radio program “Farm and Fun Time,” helped the brothers get signed to the tiny Rich-R-Tone label, in 1947. “Glass of Wine” was a poisoned murder ballad performed, like their handful of other early tracks, in the old-time string-band style. The following year they recorded “Molly and Tenbrooks,” a Bill Monroe composition that the brothers played, note for note, in the new Bill Monroe style, which, in a few years, people would start calling bluegrass. Ralph plucked his banjo not in the two-finger style he’d grown up with but in the thrilling three-finger fashion of Monroe’s star sideman, Earl Scruggs; the Clinch Mountain Boys’ Pee Wee Lambert sang lead in precise mimicry of Monroe’s piercing falsetto; and the rhythm swung hard and scooted with driving bluegrass propulsion.

Bluegrass is modern music: rhythm-centric, improvisational, scarcely older than rock and roll. It wasn’t invented until Monroe added the banjoist Scruggs and the guitarist and lead singer Lester Flatt to his band, in the late nineteen-forties. Monroe was not pleased with the Stanleys’ mimicry. When his own label, Columbia Records, signed the Stanley Brothers, in 1950, Monroe promptly left for Decca Records in a huff. But, in a real sense, the Stanleys are the reason that Monroe is remembered today as the father of bluegrass music. Monroe, with key assists from Flatt and Scruggs, invented an exciting sound. As the first to adopt that sound, Ralph and Carter Stanley helped to invent a genre.

Ralph and Carter Stanley began as copycats, but they rapidly became masters of the new sound. Carter Stanley’s songs of earthly separation, such as “The White Dove” and “The Fields Have Turned Brown,” and randy romancers, such as “How Mountain Girls Can Love,” were the equals of Monroe’s most sublime work. But it was Ralph Stanley, singing harmony with his brother or taking a lead, who truly set them apart. Ralph’s phrasing and attack on a lyric, chipping a line off short or stretching and worrying it to death and back, marked him as a Monroe disciple. The unmistakable tone and texture of Ralph’s high tenor—high and devastatingly lonesome, layered with all manner of meaning—were his alone.

To my ears, the finest music the Stanleys ever recorded was the work they cut between 1958 and 1966, for the Starday and King labels. Improved recording technology makes these sides pop more like a live performance, especially Ralph’s banjo and voice. The addition of hot acoustic-guitar picking was a Stanley innovation that is now the bluegrass standard. The period also included the brothers’ only real radio hit, an updating of “The Arkansas Traveler” called “How Far to Little Rock,” which incorporated the vaudevillian humor that was a part of their live sets. Ralph: “Hello, stranger . . . why don’t you cover your house?” Carter: “Well, when it’s raining I can’t, buddy. And when the sun’s a-shinin’ it don’t leak!”

It’s in these years that all those clichés—“force of nature,” “otherworldly”—really attached themselves to Stanley’s voice. On “Rank Stranger,” the Albert Brumley-penned gospel standard that is among the Stanleys’ most beloved performances, that voice blasts like a siren of alienated misery and end-times devastation. He sings but a single line by himself—“Everybody I met seemed to be a rank stranger”—but that utterance, just twice repeated, so dominates the record that it’s easy to forget that “Rank Stranger” is formally a Carter lead, with trio chorus.

Carter Stanley died fifty years ago this December, at forty-one, victim to liver disease and alcohol abuse. Bill Monroe, his feud with the brothers long since laid to rest, performed “Swing Low, Sweet Chariot,” a cappella, at Carter’s funeral. The inscription that Ralph Stanley chose for his brother’s tombstone read, “Farewell, Carter, for a Little While.”

This past half century, a frequent encore of Ralph Stanley’s live appearances was “The Hills of Home,” a recitation in which Ralph pledged continued devotion to his brother, to their music and their audience. Ralph had quickly determined to carry on after Carter’s death, retaining the band, the name, and the sound of the Clinch Mountain Boys. But he also made key changes, which have proved profoundly influential in their own right. He began to add more old-time ballads to his sets and his albums. He continued to emphasize gospel material as well, but he began performing it more often in the a-cappella fashion of the Primitive Baptist Church.