A Capsule is the central component of a microphone, responsible for converting the energy of sound waves into an electrical signal.

It is the part that contains the transducer (the conversion mechanism), which is usually composed of a diaphragm and other elements.

The design and type of capsule (condenser, dynamic, ribbon, etc.) are the factors that most define the sonic characteristics of a microphone, such as its frequency response, polar pattern, and sensitivity. In many high-quality studio microphones, the capsule is an interchangeable part, allowing you to change the polar pattern and the sound of the microphone.