Final answer:
In an African drumming ensemble, improvisation is typically allowed for the lead drummer, who guides the ensemble and can create spontaneous rhythms. Other ensemble members usually follow set patterns, and the ensemble's coherence relies on this structure.
Step-by-step explanation:
In an African drumming ensemble, improvisation is typically a role given to specific performers based on the structure and traditions of the ensemble. Generally, the person who is allowed to improvise is (a) the lead drummer, also known as the soloist or master drummer. This individual is responsible for guiding the ensemble, signalling changes in rhythm, and providing embellishments and variation within the performance. The lead drummer has the experience and skill to create spontaneous rhythms that enhance the musical piece without causing confusion among the other players. In contrast, other ensemble members usually play set patterns that interlock to create the overall rhythm.
It's also worth noting that each drumming ensemble may have its own unique rules and cultural practices regarding improvisation, so there can be exceptions where experienced members are permitted to improvise. However, it is less common for any member of the ensemble or the conductor (if one exists in the traditional sense) to take on this role, as the cohesion and rhythmic structure of the performance rely on clear leadership and set patterns.