Well, it is true that he recruited Doudou for the band, so he might have taught him. I wonder however who or what is behind the expertise of the singers from Extra Musica. Their choruses sound awesome, I wonder who was or is the suprvisor who could have the singers in the band sound like that. As I remember Roga-Roga and some other musicians are not from Brazzaville but Owando, where they were singing in the chruch choir in their childhood. Maybe this experience is the source of those fantastic vocal achievements of the band.