Yost died Sunday at Fort Hamilton Hospital in Hamilton, about 30 miles northwest of Cincinnati. He died of respiratory failure, hospital spokeswoman Marielou Vierling said.

The Classics IV’s hits included “Spooky,” “Stormy” and “Traces of Love.”

Yost had been in nursing homes since suffering a brain injury sustained in a 2005 fall, said Joe Glickman, the singer’s friend and biographer .

“I’m still in shock because he was fine Saturday morning,” said his wife, Linda Yost, of suburban Hamilton. “And by, you know, early Sunday morning he was gone.”

The Classics IV got their start in Jacksonville, Fla., where Yost, a native of Detroit, was raised, Glickman said. Their hit recordings were produced in Atlanta under the supervision of producer Buddy Buie and Bill Lowery, founder of Lowery Music Inc.

The group performed together for about five years.

Buie, who was a co-writer of the group’s songs with the group’s guitarist, J.R. Cobb, said: “Dennis had an incredible voice – just a great voice for love songs.”

The 67-year-old Buie, who’s retired and living in Eufaula, Ala., added: “I am deeply saddened by his passing.”

Cobb, 65, said he and Yost grew up in Jacksonville and rode motorcycles together before they were in the band.

Cobb, who later performed with the Atlanta Rhythm Section and with the Highwaymen – a country group that included Johnny Cash, Waylon Jennings, Kris Kristofferson and Willie Nelson – is retired and lives in Monticello, Ga.

“Dennis was a friend as well as a fellow musician,” said Cobb. “I always thought he had a very distinctive voice, and I think we had some of the hits we had because of him and his ability as a singer.”

Jon “Bowzer” Bauman, a vocalist with the former rock and comedy group Sha Na Na, held a benefit concert last year to help with Yost’s increasing medical costs, Glickman said.

“He was a tremendous talent who did an enormous amount of the work for that group,” said Bauman, who works against copycat performers as chairman of Truth in Music, based at the Vocal Group Hall of Fame Foundation in Sharon, Pa.

“Paradoxically, I came to know Dennis better in the later years, in which he was involved in a massive struggle to retain his own musical identity, which was one of the saddest and most difficult cases of someone losing the name of their own group, when he had pretty much been the group,” Bauman said.

Bauman said truth in music legislation has been adopted in 26 states, and a bill was expected to make it through the legislature and to the governor’s desk next week in Yost’s home state of Ohio.

Yost is survived by his wife and five children. A memorial service is planned for this weekend, Linda Yost said.