A unidirectional microphone is designed to capture sound predominantly from one direction, minimizing pickup from the sides and rear. This characteristic is achieved through its polar pattern, often cardioid-shaped, which ensures the microphone is most sensitive to sound coming from the front. This design makes unidirectional microphones particularly effective in environments with background noise or where sound sources need to be isolated, such as in live performances, broadcasting, and recording studios.

The primary advantage of unidirectional microphones is their ability to focus on a specific sound source while rejecting ambient noise. This directional quality is useful for reducing feedback in live sound situations and capturing clean audio in noisy environments. Various types of unidirectional microphones, such as cardioid, supercardioid, and hypercardioid, offer different levels of directionality and sound isolation, catering to diverse professional audio needs.