In contrast, the model that generally held for opera buffa was having two acts (as, for example, The Barber of Seville), presenting comic scenes and situations as earlier stated and using the lower male voices to the exclusion of the castrati.[6] This led to the creation of the characteristic "basso buffo", a specialist in patter who was the center of most of the comic action. (A well-known basso buffo role is Leporello in Mozart's Don Giovanni.)