George Martin, the dapper, classically trained English record producer whose exacting ear and willing spirit of experimentation helped make the Beatles the world’s most successful recording artists, died March 8, according to his manager, Adam Sharp. He was 90.

Sharp did not disclose where Mr. Martin, long known as the “fifth Beatle,” died or give a cause of death.

It was Mr. Martin who, in 1962, signed the Beatles to a contract after the Liverpool band had been rejected by every other record label they had approached.

Over eight years of collaboration, Mr. Martin produced 20 Billboard No. 1 singles for the band. Though, in his darker post-Beatles moods, John Lennon played down Mr. Martin’s contribution to the band’s success, it is doubtful that many other producers would have been as adept as Mr. Martin at helping the untutored musicians realize their sonic desires.

George Martin, left, talks at press conference in 1995. Sitting with Martin are Jeff Lynne, co-producer of the single "Free as a Bird," and Neil Aspinall, head of Apple Corps. (Kevin Lamarque/Reuters)

At their first meeting at EMI’s Abbey Road studios, Mr. Martin struck the Beatles as incredibly posh, with a precise bearing and a clipped BBC accent — “friendly, but schoolteacherly,” in the words of George Harrison. In fact, Mr. Martin’s roots were as working-class as theirs.

Born Jan. 3, 1926, in Muswell Hill in north London, George Henry Martin was the son of a carpenter and worked hard to shake his common accent. As a boy, he taught himself to play the piano, and by age 16, he had formed a band — George Martin and the Four Tune Tellers — that played school dances, performing music by the likes of Jerome Kern and Cole Porter.

Mr. Martin joined the Royal Navy’s Fleet Air Arm during World War II. After his discharge, he used a navy education grant to enroll at the respected Guildhall School of Music and Drama in London. There, he studied composition, conducting and music theory. He also took up the oboe. (One of his teachers was Margaret Asher, mother of future Paul McCartney girlfriend Jane Asher.)

Although Mr. Martin claimed never to have mastered the instrument, he became a freelance oboist, supplementing his income with money earned sorting scores at the BBC Music Library. In 1950, he joined EMI as the assistant to the head of the Parlophone label.

Parlophone was the poor stepchild in the EMI family, subsisting on a diet of jazz, light classical music and Scottish folk acts. When Mr. Martin joined the company, it still recorded some material on wax discs, not tape, and issued 78 rpm records, not LPs.

Mr. Martin ascended to the top job at Parlophone in 1955. He carved out a niche recording comedians, among them Peter Ustinov, who knew Mr. Martin through their shared affection for baroque music as well as friendships with the radio comedians Spike Milligan and the Goons, whose manic wordplay and sound effects had found a fan in Lennon.

Mr. Martin’s comedy releases were surprise hits, but he desperately wanted to land a pop star, someone along the lines of Cliff Richard, Britain’s answer to Elvis Presley. “I was frankly jealous of the seemingly easy success other people were having with such acts,” Mr. Martin wrote in his autobiography, “All You Need Is Ears.”

In 2002, former Beatles producer Sir George Martin visits a sculpture of John Lennon in a Havana park named after the musician. (Rafael Perez/Reuters)
Meeting the Beatles

On May 9, 1962, Beatles manager Brian Epstein played Mr. Martin a demo recording he had been shopping around without success. Mr. Martin was interested — “there was an unusual quality of sound, a certain roughness that I hadn’t encountered before,” he wrote — but said that he would have to hear the band in person. The Beatles drove down from Liverpool on June 6 for an audition. Mr. Martin explained how the recording process worked and what he would need from them if they wanted to be successful. He ended by saying: “Look, I’ve laid into you for quite a time. You haven’t responded. Is there anything you don’t like?”

“Well, for a start,” responded Harrison, “I don’t like your tie.”

The guitarist’s remark broke the ice. (The tie was black, with red horses on it.)

On Sept. 4, the band returned for a proper recording session with new drummer Ringo Starr, who replaced Pete Best. The band’s first single, “Love Me Do,” was recorded at that session. It reached No. 17 on the British charts.

Mr. Martin had wanted to release “How Do You Do It?,” a song written by Mitch Murray, but the Beatles were adamant that they preferred their own compositions.

“I told them they were turning down a hit,” Mr. Martin remembered. “It was their funeral, but if they were going to be so obstinate, then they had better produce something better themselves. . . . They did produce something better.”

That was “Please Please Me,” which Lennon and McCartney originally envisioned as a slow number in the style of Roy Orbison’s “Only the Lonely.” Upon hearing it, Mr. Martin pronounced it “a very dreary song” badly in need of “pepping up.” He told them they could improve it by increasing the tempo and tightening the harmonies.

The Beatles did as Mr. Martin suggested, and when the group returned to Abbey Road, “Please Please Me” was a propulsive, tumbling pop confection. After the 18th and final take, Mr. Martin announced over the intercom, “Gentlemen, you’ve just made your first number one record.” He was right. (He was right about “How Do You Do It?” as well. It went to No. 1 for another band of Liverpudlians, Gerry and the Pacemakers.)

Mr. Martin helped tweak the Beatles’ music without changing its essential qualities. It was Mr. Martin’s suggestion to start “Can’t Buy Me Love” with the ear-catching chorus of the song rather than the first verse and to replace Harrison’s intro guitar lick on “From Me to You” with a sung vocal mimicking the guitar figure: “Da da da da da dum dum da.” Mr. Martin played keyboards on the band’s early songs, including the honky-tonk piano on “Slow Down” and the electric harpsichord on “Because.”

Also critical was what Mr. Martin didn’t do. He resisted his initial urge to make one Beatle the frontman. And he didn’t force them to churn out subpar material.

“This was the first time, in essence, that an artist’s career had been sensibly built,” said author and Beatles expert Mark Lewisohn.

A classical ear

Mr. Martin used his classical training to clothe the band’s songs in musical raiment that was unprecedented for pop songs of the time. When McCartney played him the ballad “Yesterday,” Mr. Martin suggested that it would sound better with a string quartet.

His score for “Eleanor Rigby” was inspired, he said, by the work of Bernard Herrmann, who composed the soundtracks for Alfred Hitchcock’s “Psycho” and François Truffaut’s “Fahrenheit 451.”

As the studio increasingly became the Beatles’ playground, Mr. Martin helped make concrete the sounds they heard in their heads, a collaboration that reached its zenith with 1967’s “Sgt. Pepper’s Lonely Hearts Club Band,” the album that became the soundtrack for the Summer of Love.

To achieve the trippy circus-organ sounds on “Being for the Benefit of Mr. Kite,” Mr. Martin assembled a collection of recordings of old Victorian steam organs. He dubbed a few of the records onto tape, had an engineer cut the tape into lengths about a foot long, then flung them in the air and spliced them together, some forward, some backward. For the album-closing “A Day in the Life,” he filled the 24 bars of silence between two disparate sections by instructing symphony musicians to start at the lowest possible note for their instruments and slide gracefully to the highest possible note nearest E major, an effect he described as an “orchestral orgasm” and Lennon said sounded “like the end of the world.”

Mr. Martin said knew that the Beatles at the time were heavily into drugs, but he did not partake. He said decades later: “There’s no doubt that if I too had been on dope, ‘Pepper’ would never have been the album it was. Perhaps it was the combination of dope and no dope that worked, who knows?”

While Mr. Martin will best be remembered for his work with the Beatles, he had success with many other acts, including Cilla Black, Shirley Bassey and America. After the Beatles split, he wrote the score for the James Bond film “Live and Let Die” and produced McCartney’s theme song for it. He also wrote the score for the Robert Stigwood-produced “Sgt. Pepper” movie.

As concerned with the technical side of recording as the creative side, Mr. Martin in 1965 formed Associated Independent Recording. His custom-built AIR Studios in London and on the Caribbean island of Montserrat (the latter studio was destroyed in 1989 by Hurricane Hugo) were used by such artists as the Rolling Stones, the Police and Stevie Wonder.

Over his career, Mr. Martin won six Grammy Awards and produced a record 23 Billboard No. 1 hits, the last one being Elton John’s “Candle in the Wind,” released in 1997. He was knighted in 1996 and was inducted into the Rock and Roll Hall of Fame in 1999.

Concerned that a lifetime spent listening to loud music had compromised his hearing — he considered the ears a producer’s most important asset — he retired from producing in 1998.

His marriage to Sheena Chis­holm ended in divorce. Mr. Martin later married Judy Lockhart-Smith, his secretary at Parlophone. His survivors include two children from his first marriage, Alexis and Greg, and two from his second, Lucie and Giles. Son Giles is also a producer and has worked on reissues of the Beatles material.

In 1964, Mr. Martin accompanied the Beatles on their first trip to the United States, and he was in the audience at the Washington Coliseum for their first North American concert performance. The teenage girl seated next to him, unaware of who he was, asked, “Do you like them, too, sir?”

“Yes, I do, rather,” Mr. Martin answered.