yeah, lee perry (& king tubby) used to make loads of dubs, then get people in to sing over the top. thats why there are so many reggae tracks that use the same dub. even today reggae uses a similar technique, those dancehall greensleeves albums, use 1 rhythm throughout and get different artists to sing over the top. kinda like stock car racing, everyone gets a standard and have to show what they can do.