Everyone knows how much of black popular music comes out of the church, but fewer will be aware that the black churches once exploited the record industry to counter the astonishing advance of profane culture. The sanctified stars of soul and r’n’b run from the Revd Al Green and “Sister” Aretha Franklin, but what of names like the Revd James Gates and Calvin P. Dixon, who went out as “Black Billy Sunday” and who between 1925 and 1941 were among around 100 African-American clergymen contracted to major labels like Columbia, Paramount and RCA to make recordings of sermons and who became stars as a result?Sound recording was not ­– it now seems perverse to say – originally considered suitable for music, and speech recordings were an importa