double in brass

To perform multiple roles or duties; to serve in two capacities at a given time. Originally a reference to a musician in an ensemble who plays more than one instrument, especially among brass players. During the financial crisis, after many of our staff had been laid off, we were all expected to double in brass to maintain the company's level of productivity.

Serve in two capacities, as in In this company everyone is asked to double in brass occasionally. This expression was originally used in the traveling circus, where, for example, a clown was also expected to play an instrument in the street parade. The original allusion, however, is to an instrumentalist who plays more than one instrument in an ensemble, a practice particularly common among players of brass instruments. [Late 1800s]