A super-cardioid is one type of unidirectional condenser microphone. A unidirectional microphone is distinct from an omnidirectional because it has a much more focused pickup area, rejecting sound from outside where the capsule is pointed. The term “cardioid” refers to the polar pattern of the a microphone, so-called because the pattern resembles a heart.
When someone is delivering a speech, it’s essential that their voice is amplified loudly and clearly with as little background noise or interference as possible. In other applications, such as choral singing, it’s desirable to pick up ambiance as well as the source sound. Studios invest lots of money in microphones that do this. But for a speech, the super-cardioid is ideal because its polar pattern cancels out any noise coming from anywhere but the speaker's mouth. The slender styles you see on a lectern are super-cardioid microphones.
Some recording techniques call for a microphone that colors the tone of the singer’s voice. However, when a clear, crisp and unaffected vocal is called for, the super-cardioid is most suitable. Because it has a larger polar pattern than a regular cardioid microphone, it's capable of collecting a broader scope of sound from the singer. This broader scope is still unidirectional, meaning only the singer is recorded. Super-cardioid microphones are particularly useful for recording and amplifying singers performing outdoors, as they cut out wind and other interference.
Directional Live Sound
In an orchestral setting, a big challenge is separating the instruments for recording, and a microphone with a defined directional area of pickup is most suitable. The super-cardioid is capable of capturing a clean, isolated sound in a noisy environment. It is similar to a cardioid microphone but has a larger area of pickup, although still in only one direction. Due to its unidirectional polarity, the super cardioid is able to pick out a sound from a collection of sounds.
Recording Soloists in an Ensemble
When a rock band records, members have the option to record separately or use separate rooms simultaneous recording. But it’s impractical for each musician in a large ensemble, such as an orchestra, to record separately. An orchestral recording typically calls for a combination of microphones -- some to record the ambiance and some to record individual instruments. A super-cardioid is suitable because it can be placed among a group of loud instruments and reliably pick up only the sound of the preferred instrument. This means the isolated solo track can be mixed louder for a more coherent recording.