Pre-doo-wop (before 1948)

not present or used in different ways

humming or very much in background

occasionally present but has operatic quality

frequent bass leads and talking bridges, but not between stanzas, not distinct from harmony under the lead

allied with jazz, r&b or other earlier styles

heavier than standard doo-wop fare

blues or jazz progressions

often lacivious in R&B,else mature love themes