Apple will begin manufacturing its AirPod headphones in Vietnam this quarter, forming part of the group’s longer-term diversification plans linked to labor costs and risk management rather than being a snap reaction to tariffs and COVID-19. Vietnam is becoming an audio manufacturing hub as firms move away from China for sales into the U.S. market. China’s share of U.S. headphone imports fell to 57.7% in Q1 from 76.1% in 2017. Vietnam’s share rose to 22.1% from 4.7% over the same period. That growth has been driven by a handful of manufacturers including Samsung Electronics, with shipment...