NASHVILLE (AP) — The sound of voices in synch filled the air as two of country music's greatest vocal harmony groups, the Oak Ridge Boys and the Browns, along with the late gifted guitarist Grady Martin were inducted into the Country Music Hall of Fame on Sunday night.

On hand to honor the 2015 inductees were Garth Brooks, Trisha Yearwood, Dierks Bentley, Vince Gill and Marty Stuart with performances of hits like "Elvira," ''The Three Bells" and "El Paso."

The four members of the Oak Ridge Boys, Joe Bonsall, Duane Allen, William Lee Golden and Richard Sterban, each received a medallion from their longtime friend and tour mate, Kenny Rogers.

Brooks, who is nominated for entertainer of the year at the Country Music Association Awards next month, said the Oak Ridge Boys gave him his start as a young artist in the 1980s.

"So they opened the doors for me, but what they really did, long before that — 'Y'all Come Back Saloon,' might be one of the greatest albums ever recorded in country music history," Brooks said before the ceremony. "Great song after song, hit after hit."

The four newest members of the hall have all been performing together since 1973, although the band's origins date back to the 1940s. They are one of the few gospel acts to successfully transition to secular music and become hit-makers in multiple genres.

"It's always been family," Bonsall said during the ceremony. "Family has been what's most important. We've tried to run our group that way, as a family."

The Browns, a sibling trio made up of Jim Ed Brown and his sisters Maxine and Bonnie, established themselves as smooth harmony singers in the 1950s and '60s with songs like "The Old Lamplighter" and "Scarlet Ribbons (for Her Hair.)" When Maxine and Bonnie left the business to raise their children, Jim Ed Brown continued on as a popular solo artist who had a successful run as a radio and television host as well.

Jim Ed Brown was inducted into the hall of fame at his bedside a few days before his death in June from cancer, and his sister, Bonnie, announced earlier this month that she has also diagnosed with cancer.

Bentley, who performed Jim Ed Brown's "Pop A Top," said Brown was like a father figure at the Grand Ole Opry when Bentley first started performing there.

"He's probably up there looking down on us and will probably be in the room tonight when we're singing, and I'll be nervous," Bentley said before the ceremony.

Few musicians have had a career like Martin, a guitar and fiddle player who performed with musical legends like Hank Williams, Elvis Presley, Johnny Cash, Patsy Cline and Willie Nelson. He could play just about any style, from acoustic, rockabilly, rock 'n' roll or twangy country.

One famous story about Martin was how he created his signature guitar lick on Marty Robbins' hit, "Don't Worry." A preamp in the studio mixing board malfunctioned, which gave his solo guitar part a fuzzed-out sound that became so popular that even Keith Richards replicated it for the Rolling Stones.

Martin died in 2001. Singer Brenda Lee presented the medallion to his son, Joshua Martin.