Cardioid Microphones

Cardioid Microphones are microphones primarily used for picking up sounds with high gain from the front and sides but poorly from the rear. Their name comes from their directional sound pickup being roughly heart-shaped. Cardioid microphones are most sensitive to sound arriving on-axis, directly in front of the microphone. They are still relatively sensitive to their sides (as above and below) at 90 and 270 degrees. Additionally, they have a null point (the angle of sensitivity or most rejection) at 180 degrees directly behind the microphone. We can distinguish a few types of cardioid microphones, which are:

Hypercardioid Microphones

They are less sensitive to sound coming from the sides (and above and below) than cardioid microphones- although they still exhibit some pickup from the sides, above and below. This makes them more directional- they focus more on sound directly in front and reject more off-axis sound than a cardioid microphone. An unavoidable trade-off of the hypercardioid pattern is an area of slight sensitivity at 180 degrees directly behind the microphone. This means the null points are 35 and 45 degrees displaced from the rear of the microphone.

Omnidirectional Microphones

They are picking up sounds coming from all directions more evenly. Furthermore, graphic representations resembling the shape of a circle typically represent them. However, all microphones become more directional at higher frequencies. So, it is still important to point an omnidirectional microphone in the right direction, on the axis of the sound source. An omnidirectional microphone will pick up more spills (sound from adjacent sound sources, not intended to go into the microphone) and off-axis room reflections than a directional microphone. This additional spill may or may not be desirable; it depends on the source, the role of the mix, the room, the type of project, and the desired production and mix style. Omnidirectional microphones have more open and transparent sound than directional microphones and can generally be positioned closer to sound sources than directional microphones without sounding boomy or muddy.

Wide Cardioid Microphones

They are typically less directional than cardioids but more directional than omnidirectional microphones. They favor sound from the hemisphere in front of the microphone, but they are equally sensitive to sound from the sides (above and below). Their null point is the region directly behind the microphone. Also, their image usually represents a polar pattern. Their sound tends to balance the openness of omnidirectional microphones and some of the directional control of cardioid microphones.