History: A disadvantage of additive synthesis is...

A disadvantage of additive synthesis is...

• Additive synthesis can be expensive for the human to design.
  Some very complex forms, sure, but not all additive synthesis is complex.
• Additive synthesis can be expensive for the computer to calculate.
  Yes.
• Additive synthesis can be cheap for the computer to calculate.
  This doesn't make sense. Cheap would be an advantage.
• Additive synthesis can be expensive for the human to execute.
  Interface design is irrelevant to this unit.