Cardioid and Super-cardioid are terms usually associated with microphones and its good to understand both because it is easy to mistake the function of one for the other.
Cardioid and supercardioid simply means the reception pattern of microphones. They are usually represented as polar plots.
Cardioid microphones are more sensitive to sound coming from in front of them (on axis) as well as a bit from the sides, generally -90 to +90 degrees off axis.
They are useful when trying to pick up signals from the sides as in a room.
A Supercardioid microphone on the other hand has a tighter reception pattern making them more directional. They are basically sensitive on axis but tend to reject sounds coming from the sides or from further off axis. They are useful when trying to isolate a sound by reducing “bleed over” from an adjacent sound.
Cardioid microphones are combination of two patterns; Omnidirectional and bidirectional.
Omnidirectional simply means picking up signals from all directions.
Bidirectional means picking up signals from two sides (usually opposing sides).
Combining these techniques led to the development of the Cardioid microphones which are also termed as Uni-directional microphones.
Cardioid Microphone Uses
You certainly need to know when to use cardioid Microphones because you don’t want to subject them to situations that they cannot handle or can be handled by a different microphone.
Cardioid microphones can be great for recording instruments for example a guitar or a keyboard.
The cardioid mic despite keeping leaks and room noises away, can pick up the characteristic sound of the instrument.
With the ability of cardioid Microphones being able to pick up signals from the front, it’s the best mic that you can use to record instruments like guitar because you can simply set up the instrument in front of the microphone and it will record everything coming toward its axis.
Some bands might like to keep the energy of the live performance in their studio recordings as well.
Therefore cardioid microphones are the perfect tool for such kind of work.
Avoiding leaks of one instrument into another. For example: the microphone of the singer will pick up much less volume from the acoustic guitar played by him or her.
That makes all the difference in the editing, equalizing and mixing of your final recording because you won’t have to deal with vocal takes being flooded with other instruments.
Cardioid microphones are also perfect for on stage performances. This is because they can allow the lead singer to be able to shield their vocal from the background instrumentation so their voice can be properly heard by the crowd.
Furthermore, cardioid Microphones can also be useful in rooms that are not acoustically treated for sound because the mic can deal with sound reflections a whole lot better.
Drawbacks of Cardioid microphones
Off-axis coloration – With most cardioid mics, you see a drop in high frequency sensitivity as sounds move further off-axis and more to the sides.
This could be bad, for instance, with an inexperienced singer making unconscious head movements because it could lead to poor inconsistent recordings
Proximity effect – This is common with cardioid mics…the proximity effect is a boost in bass frequencies that results from being extremely close to the microphone.
Using the same “inexperienced singer” example, you can see how this might also cause problems.
The proximity effect can damage recording takes especially if the microphone isn’t well placed with a Pop Filter or placed well enough to counteract any proximity issues.
Super Cardioid microphones
As opposed to a cardioid mic, supercardioid microphone have a very directional supercardioid polar/pickup pattern.
They are generally most sensitive to on-axis sounds which is where the mic points .
Supercardioid mics are popular in film due to their high directionality.
When to use Super Cardioid microphones
When someone is delivering a speech, it’s key to have their voice amplified loudly and clearly with little background noise or interference being projected into the mic.
This makes the super-cardioid ideal because its polar pattern cancels out any noise coming from the sides and only picks up what’s coming into the front which is the speaker’s voice.
If you’re going for a clear, crisp and unaffected vocal, 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 basically unidirectional which means that only the singers voice is recorded.
Super-cardioid microphones are useful for recording and amplifying singers performing outdoors because they naturally reject wind and other interference that may otherwise be captured by an ordinary cardioid or omnidirectional microphone.
When dealing with a situation where instruments have to be recorded all at once by separate microphones like in the case of an orchestra.
A super-cardioid is suitable for this because it can be placed among a group of loud instruments and it can reliably pick up only the sound of the preferred instrument. This means the isolated solo track can be mixed louder for a more composed recording.
The Downside to supercardioid microphones.
The main Downside is that the pick up pattern of supercardioid microphones is focused on its axis which means it can reject signals from other directions with ease.
Therefore any situation that may have a supercardioid microphone used to record omnidirectional signals will result in poor recordings because these mics are not designed for this.
However it’s narrow focused pick up pattern certainly has its advantages.