Hoskyns described the "core sound" of Waits' early work as being that of a "Beat verse/jazz-trio". There were jazz elements in Waits' early work. During his "Blue Valentine" tour, Waits began experimenting more with sounds derived from the blues, with Humphries arguing that Waits had "always been indebted" to the blues. In later life, he preferred to be thought of as a blues singer, although accepted the label of a folk singer. Waits has made use of blues, jazz, and vaudeville, and experimental. Waits described his voice as being "the sand in the sandwich". In 2008, he modelled some of his early vocal mannerisms after Richard Buckley. Waits was usually reticent to discuss the specifics of his song-writing with journalists. His work was influenced by his voracious reading and by conversations that he overheard in diners. A major influence was the Beat writer Jack Kerouac, although other writers who inspired him included Charles Bukowski, Nelson Algren, John Rechy, and Hubert Selby Jr. He was also inspired by the comedian Lenny Bruce. Musically, he was influenced by Randy Newman, and Dr. John. He regarded James Brown as one of his musical heroes, and was also a great fan of the Rolling Stones. He has praised Dylan, noting that "for a songwriter, Dylan is as essential as a hammer and nails and saw are to a carpenter", as well as the country musician Merle Haggard, relating: "Want to learn how to write songs? Listen to Merle Haggard." As of 1982, Waits' musical style shifted; Hoskyns noted that this new style "was fashioned out of diverse and disparate ingredients". This new style was influenced by Captain Beefheart and Harry Partch. Noting that he had a "gravelly timbre" to his voice, Humphries characterized Waits' voice as one that "sounds like it was hauled through Hades in a dredger". His voice was described by critic Daniel Durchholz as sounding as though "it was soaked in a vat of bourbon, left hanging in the smokehouse for a few months, and then taken outside and run over with a car". "Rolling Stone" also noted his "rusted plow-blade voice". One of Waits' own favorite descriptions of his vocal style was that of "Louis Armstrong and Ethel Merman meeting in Hell".