 Wide separation in the stereo image ensured that subtleties in the musical arrangements were heard; in Riley's description, this quality emphasised the "richly textured" arrangements over "everything being stirred together into one high-velocity mass".Until late in their career, the "primary" version of the Beatles' albums was always the monophonic mix.According to Beatles historian Bruce Spizer, Martin and the EMI engineers devoted most of their time and attention to the mono mixdowns, and generally regarded stereo as a gimmick.