Microphone capsule directivity describes the pickup range of the microphone from different angles. Typically, the specification is represented by a directivity pattern diagram. In each diagram, the top of the dashed circle represents the front of the microphone, while the bottom represents the rear.
The pickup pattern of a microphone capsule indicates its sensitivity to sounds from various directions or angles. Simply put, it reflects the microphone's ability to "hear" sounds from different directions. The most common types of microphone capsule directivity are: Omnidirectional (Omnidirectional Capsule), Cardioid, Supercardioid, Shotgun (Unidirectional Capsule), and Bidirectional (Bidirectional Capsule).
Microphone Capsule Directivity Patterns
Omnidirectional
Omnidirectional microphone capsules have equal sensitivity from all angles, allowing them to pick up sound uniformly from every direction. This means that the microphone does not need to be aimed at a specific direction, which is particularly useful for lapel microphones. However, the drawback is that it cannot avoid unwanted sound sources, such as loudspeakers, which may result in echo.
Cardioid
Cardioid microphone capsules have the strongest sensitivity at the front (usually marked with a logo) and weaker sensitivity at the back. This pattern is optimized for capturing sound from the front while attenuating sounds from other directions. This directional pickup can isolate unnecessary ambient noise and reduce echo better than omnidirectional microphones. Therefore, cardioid microphones are especially suitable for noisy stage environments.
Supercardioid
Supercardioid microphone capsules have a narrower pickup area than cardioid microphones, effectively eliminating surrounding noise. However, they also pick up sound from the rear, so monitoring speakers must be positioned correctly. Supercardioid microphones are most suitable for capturing a single sound source in noisy environments and are highly effective at echo cancellation.
Shotgun
Shotgun microphones, also known as boom mics, typically use a shotgun or supercardioid directivity. They feature extremely focused pickup patterns, minimizing environmental noise from the sides and rear, allowing for clear recording of the primary sound source. They excel at capturing sound from a specific direction.
Bidirectional
Bidirectional microphone capsules pick up sound from both the front and rear while minimizing sound from the sides (at 90 degrees). This pattern was commonly used in early ribbon microphones.
