The polar patterns of a microphone indicate how sensitive it is to sounds coming from different angles about its central axis. Some microphones are directional and only pick up from a particular direction whereas others will pick up from all around.

There are essentially five main polar responses or pick-up patterns, these are:

Cardioid Patterns – With a Cardioid pattern (the name coming from the heart shape of the pattern) the vast majority of the sound is picked up from the front of the microphone with a reasonable amount from the sides. Very little, however, is picked up from behind.

As a result, you can point this microphone at the sound you want to pick up. This is probably the most commonly used pattern you will come across as it is very versatile and can be used in practically all situations.

Hyper-Cardioid Patterns – Hyper-Cardioid microphones have a similar pattern to cardioid but the response from the sides (referred to as off-axis) is less. This makes it more directional than the Cardioid. Hyper Cardioid microphones are used when isolation between sound sources is important.

They are less sensitive to off-axis sounds and will not pick up near-by sources as easily. Another common use is when used live and there is a feedback problem. Hyper-Cardioid microphones are less likely to pick up sound spill from speakers due to their more directional nature and thus reduce the chances of feedback occurring.

Shotgun Patterns - Shotgun microphones have a very tight pickup pattern and are highly directional. They have small lobes of sensitivity to the left, right, and rear but are significantly more sensitive to the front. This results from placing the element inside a tube with slots cut along the side; wave-cancellation eliminates most of the off-axis noise.

They are used primarily to pick up sounds from a distance, for example, the recording of wildlife. Shotgun microphones are also commonly used on TV and film sets. Uses are in broadcast/film recording work are where the microphone can be held or suspended 'off-camera' and in the theatre for picking up actors on stage without having to individually microphone them all.

Due to the sensitivity of these microphones, they are all condensers and, as such, require a phantom power supply.

Omni-directional Patterns – Omni-directional microphones pick up sound from all directions equally as can be seen from the polar response. They tend to produce the most natural sound of all the pickup patterns, capturing the sound source plus all the other acoustic reverberations and nuances.

Omni directional microphones are also not susceptible to the Proximity Effect as are Cardioids. As such, they are used mainly for recording work. Omni's are not normally used for live work, as they would pick up unwanted sounds such as the audience and sound from speakers, creating one horrendous feedback problem.

Figure 8 Patterns - Figure-of-8 microphones again tend to find their use for recording work, picking up sound from the front and rear of the microphone but not from the sides. They are often used when making stereo recordings.