06 - Advert - Buddy Holly & The Crickets on Coral Records, a photo by Bradford Timeline on Flickr.
""For us, it was more of a rock 'n' roll kind of thing," Jerry Allison said. "Other guys were more interested in country than Buddy and I were. We started listening to rock music," taking advantage of the radio "skip" phenomenon that lets listeners tap into faraway stations.
"It was kind of hard to find, but we could get a station out of Shreveport [La.] when all the other radio stations would go off at dark," Allison said. "We'd sit around the fire and listen to 'em."
Those tunes were the inspiration for "That'll Be the Day," he said.
Curtis could even name the day that the band shifted to rock: Jan. 7, 1955."
From a Chuck Yarborough story at Cleveland.com.