This line-up may at first seem dull but it must be appreciated that as the boys have above average instrumental ability they achieve surprisingly varied effects. Their basis beat is off-beat, but this has recently tended to be accompanied by a faint on-beat; thus the overall sound is rather reminiscent of the four in the bar of traditional jazz. This could possibly be put down to the influence of Mr McCartney [Senior], who led one of the top local jazz bands (Jim Mac’s Jazz Band) in the 1920s.
A very young Paul McCartney struggling to describe the Beatles style circa 1960
Taken from the very intriguing Early Beatles Songs website. Check it out.