The directional characteristic indicates the sensitivity of a microphone depending on the angle of incidence. The reference is the 0-axis as the main sound source. The directional characteristic is illustrated by directional diagrams. The directional characteristic is not the same over the entire frequency spectrum but varies depending on the frequency. For this reason, the directional diagrams show the characteristic curve uniformly at 1 kHz. Basically, it can be said that the directional characteristic is significantly weaker at low frequencies than at high frequencies.
There are two main directional patterns: the omnidirectional pattern and the cardioid pattern.
With the omnidirectional pattern, the sound is received from every direction in the same direction, which is why the term omnidirectional is often used.
With the cardioid characteristic, on the other hand, only the sound from the front is converted. On the rear axes (180°), there is theoretically almost 100% attenuation, apart from reflections. In practice, the attenuation is around 20-35 dB. The cardioid characteristic of a microphone is often referred to as unidirectional.