Red Simpson, a pioneer of the "Bakersfield sound" and an icon in the sub-genre of country trucking songs, has died unexpectedly. He was 81.

According to the Bakersfield Californian, Simpson had suffered a heart attack on Dec. 18, after returning from a tour. Family friend Gene Thome tells the paper, "He seemed to be doing better," but on Friday night (Jan. 8), Simpson went into cardiac arrest and could not be revived.

Born on March 6, 1934, in Higley, Ariz., and raised in Bakersfield, Calif., Simpson was the youngest of 13 children in a musical family. One of his older brothers, Buster Simpson, played in Bill Woods' Orange Blossom Playboys, and when he died unexpectedly in 1952, Woods "took Red under his wing," according to the biography on Red Simpson's official website.

After his brother's death, Simpson joined the Navy and spent time in Korea, forming the Repose Ramblers with some fellow servicemen. The future icon left the Navy in 1955 and learned sheet metal work at Bakersfield College. He began filling in as a guitarist when Woods played at local club the Blackboard; he also learned to play the piano and became the Clover Club's pianist.

Simpson cut singles on Tally Records, Millie Records and Lute Records. He signed with Capitol in 1966 and earned a Top 10 album with Roll, Truck, Roll. Between 1966 and 1973, he recorded eight albums and earned two Top 40 singles and one Top 5 single, the latter being "I'm a Truck." On the road, Simpson opened shows for Buck Owens and Merle Haggard.

"He played a huge part in the Bakersfield sound and was a dear friend of mine for over 50 years," Haggard writes on Facebook in remembrance. "One of the original musicians on "Okie from Muskogee." RIP Red Simpson."

Almost 200 artists have recorded Simpson's songs. He stopped touring in 1984, opting instead to perform in the Bakersfield area, including at Trout's on Monday nights for more than 20 years. In March of 2012, he headlined the grand opening of the Country Music Hall of Fame's exhibit on the Bakersfield sound.

Simpson was planning to release a brand-new album, Soda Pops and Saturdays on Feb. 4. Also in February, he was to receive the Founder of the Sound honor at the Ameripolitan Music Awards.

"Red loved everyone, and he leaves this world loved in return by all of his friends and family," a post on Simpson's Facebook page reads. "He was such a caring and wonderful man that he has been described as 'a walking heart' ... We know you're up there in truck drivers heaven singin' and playin' "Truck Drivin' Man" ..."

Arrangements for Simpson are still pending; his family says that "loving and caring comments are very much appreciated" but asks for privacy "to give time to be together and get through this tough time." According to another Facebook post, a show in honor of Simpson will take place at the Rustic Rail in Bakersfield on Saturday (Jan. 9) at 5PM. Simpson's son David will be performing, and Soda Pops and Saturdays will be available for purchase, with the proceeds going "to support the family at this time."

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