2: Polar Pattern's

Microphones: Polar pattern / Directionality
Polar pattern graphs visually represent the microphones sensitivity to sound relative to the direction or angle from which the sound arrives. Or in other words, how well the microphone “hears“ sound from different directions. The most common types of directionality, plotted as polar patterns are: Omnidirectional, Cardioid and Supercardioid.


Cardioid

Cardioid microphones are most sensitive to sound at the front and least sensitive at the back. Their unidirectional pickup makes for affective isolation of unwanted ambient sound and high resistance to feedback when compared to omnidirectional alternatives.

Cardioid microphones are essential when considering a mic for live performance.




Supercardioid

Supercardioid microphones offer a narrower pickup than cardioids and a greater rejection of ambient sound. However, they also pick up a small amount of sound from directly behind. For this reason, it is particularly important to place monitor speakers to the side facing the 'dead spots'.

Supercardioids are highly suited to very loud stage environments as they are very directional with high gain before feedback.



Omnidirectional

Omnidirectional microphones are equally sensitive to sound arriving from all angles. Therefore, the microphone does not need to be aimed in any particular direction. This can be particularly useful when using a lapel mic to capture a speakers voice, as the individual can move their head without affecting the sound.

The disadvantage is that an omni mic cannot be aimed away from undesired sources, such as PA speakers, which may cause feedback.


Figure of Eight (bidirectional)

A microphone with a figure-of-eight polar pattern picks up the sound from in front of the microphone and from the rear but not the sides (90 degree angle).

Microphones with a figure-of-eight polar pattern are typically ribbon or large diaphragm condenser microphones.







 Proximity Effect
All directional microphones (i.e. cardioid, supercardioid) are subject to the proximity effect.

'Proximity effect' happens when the microphone moves closer to the sound source, resulting in an increase in bass response. Professional singers often work with this effect to increase 'warmth' when desirable.

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