The Allmans were known for fusing elements of southern rock, blues, jazz and country music with their own sound.
After unfulfilling experiences with the music industry in Los Angeles, Gregg and Duane ended up in Macon, Georgia - hometown of Little Richard and Otis Redding - in 1969 and brought together the Allman Brothers Band.
The brothers had no particular inclination for music but Allman cited two influences that inspired him - a concert he and his brother attended in Nashville in 1960 and a mentally-challenged neighbour who taught him to play the guitar.
In a 2012 interview with CMT News, Gregg Allman candidly discussed the myriad of health issues he had experienced since the late 1990s, some three years after he quit drinking. All his 2017 tour dates, including 10 nights at City Winery in NY in July, were canceled in mid-March.More news: Liam Gallagher: 'I'd prefer to be in Oasis than go solo'
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Michael Lehman, Allman's longtime manager, called his close friend "a brilliant pioneer in music". "I thought that's the hippest thing I've ever heard". His love for his family and his band was extraordinary, just as he loved his fans.
Gregg Allman was blessed with one of blues-rock's great growling voices and, along with his Hammond B-3 organ playing (beholden to Booker T. Jones), had a deep emotional power. I've lost too many lately and this one is gonna be hard to get past.
The rockers rose to prominence after the release of their third album "At Fillmore East". And what's amusing, I think, is that the Allmans were so instrumental in the genesis of what we now call southern rock - you know, a genre that's associated perhaps unfairly with Confederate flags and pickup trucks and all this sort of iconography that suggests, you know, an unwelcoming or an outdated worldview - that it's easy to forget they were revolutionary inclusive at the time.
Duane Allman spent time in the Shoals before the formation of the Allman Brothers band, working as a studio guitarist. We revisit Allman's last visit to World Cafe in 2011, when he performed songs from his seventh solo studio album, Low Country Blues.
Keith Urban added: My heart breaks today at the passing of soul brutha Gregg Allman. My fondest memories will always be of Gregg, myself, and Allen Woody sharing a tour bus together-listening to great music and laughing our asses off mile after mile.
Duane Allman had quickly ascended to the pantheon of guitar heroes, not just from his contributions to the Allman band, but from his session work with Aretha Franklin, Wilson Pickett and with Eric Clapton on the classic "Layla and Other Assorted Love Songs" album. "I don't understand why he can't see it".