Bob Babbitt, of the Funk Brothers, plays bass during a Funk Brothers performance in Cleveland in April 2003. (Luke Palmisano/AP)

Bob Babbitt, a bassist for Motown Records and key accompanist to some of the recording studio’s biggest stars, including Stevie Wonder, Marvin Gaye and the Temptations, died July 16at a hospice near his home in Nashville. He was 74.

His wife, Ann Kreinar, confirmed the death and said the cause was a brain tumor.

Mr. Babbitt was part of a core group of Motown musicians nicknamed the Funk Brothers for their dazzling way with hook-laden rhythms. The group — they were almost never credited on records — included bassist James Jamerson, guitarists Robert White and Joe Messina, keyboardists Joe Hunter and Earl Van Dyke, and drummers Benny Benjamin, Richard Allen and Uriel Jones.

Along with guitarists Messina and Dennis Coffey, Mr. Babbitt was one of the few white members among the predominantly African American group. In the acclaimed 2002 documentary “Standing in the Shadows of Motown,” which tells the saga of the Funk Brothers, Mr. Babbitt remarked, “There was such a closeness. When Martin Luther King died, they never expressed to me any kind of hostility. And I felt as sad as they did.”

Mr. Babbitt came to Motown in 1967, when the label was shifting away from its shuffle and cha-cha-based rhythms into more syncopation and psychedelic soul. He credited Jamerson with bringing him to the label’s staff. The two bassists met during sessions at Golden World, a studio that briefly competed with Motown in Detroit and was later purchased by Motown President Berry Gordy Jr.

Mr. Babbitt’s bass playing was featured on Smokey Robinson and the Miracles’ “Tears of a Clown,” Edwin Starr’s “War,” the Temptations’ “Ball of Confusion,” Marvin Gaye’s “Inner City Blues (Make Me Wanna Holler)” and Stevie Wonder’s “Signed, Sealed, Delivered I’m Yours.”

In addition, his credits outside of the Motown studio included the Parliaments’ “(I Wanna) Testify” (1967), the first national hit for George Clinton’s P-Funk acts; the Capitols’ “Cool Jerk” (1967) and pop singer Del Shannon’s “Little Town Flirt” (1963).

Mr. Babbitt played solo for nearly 90 seconds on bass guitar on Coffey’s funk instrumental “Scorpio” (1971), a Top 40 radio hit.

When the Motown company left Detroit for California in 1972, Mr. Babbitt came east, where his New York City credits included sessions with Elton John, Barry Manilow and Gladys Knight and the Pips’ “Midnight Train to Georgia” (1973). He later worked for producer Thom Bell as part of the studio group MSFB in Philadelphia and toured with folk entertainer Joan Baez and rock singer Robert Palmer.

Mr. Babbitt found that the key to his work in the studio was blending in — and not just musically. He recalled a three-week period in the early 1970s when he did sessions for soul vocal group the Spinners in Los Angeles, hard rocker Alice Cooper in Toronto and then the basic instrumental tracks for a Frank Sinatra record in New York.

“For Frank I wore a suit jacket,” he told a trade journal for New York musicians. “I had jogging clothes on in L.A., and in Toronto I wore a pair of pants that were ripped and some funky old rock-and-roll jacket.”

“Some of the [bass] lines might have been different,” he added. “But the main difference was in the styles, and the way I dressed, which had nothing to do with the record, of course.”

Mr. Babbitt was born Robert Kreinar in Pittsburgh on Nov. 26, 1937. His father, a Hungarian immigrant, was a bricklayer. As a youngster, Mr. Babbitt studied classical upright bass but, as a teenager, his tastes drifted toward rhythm-and-blues. He began performing in nightclubs on the louder and more portable electric bass guitar.

In 1961, he moved to the Detroit area, joined the local band The Royaltones and played on its instrumental hit “Flamingo Express.” The Royaltones later became the touring band for singer Del Shannon.

Survivors include his wife of 54 years, Ann Efantedes Kreinar of Nashville; three children, Caroline Cummings of Hightstown, N.J., Karen Notzelman of North Port, Fla., and Joseph Kreinar of Somerset, N.J.; a brother, Charles Kreinar of Woodbridge; and two granddaughters.

In the mid-1980s, Mr. Babbitt attempted to establish himself in Nashville and said his Motown credits did not automatically translate to studio work in the country music capital.

“I couldn’t get producers on the phone,” he told the Nashville Tennessean in 2003. “My friend [drummer] Larrie London said, ‘You’ve got to start eating lunch at the San Antonio Taco House, because that’s where all the writers and producers hang out.’ I said, ‘What do I do, strap my bass on, get some business cards and sit there at a little table?’ ”

He added that his expertise in groovy rhythm-and-blues did not favor the slower and simpler country music sound.

“If I had it to do all over again, I would have moved to Nashville and used Kreinar as my name and not tell anybody anything about Motown,” he told the Tennessean. “I’d just be a bass player in town.”