Polar Patterns describe the way in which a microphone picks up the sound from around it. 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 ? 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 mic 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 ? 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 ? Shotgun microphones have a very tight pickup pattern and are highly directional. They are used primarily to pick up sounds from a distance.
Common uses are in broadcast/film recording work where the mic can be held or suspended 'off-camera' and in the theatre for picking up actors on stage without having to individually mic them all. Due to the sensitivity of these microphones, they are all condensers and, as such, require a phantom power supply. Omni-directional ? 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.
They 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 ? Figure-of-8 microphones again tend to find their use for recording work, picking up sound from the front and rear of the mic but not from the sides. They are often used when making stereo recordings.
Ian Marples has been playing guitar for over 10 years, and now runs the website http://www.uncleslinky.co.uk to help other guitarists learn how to succesfully record music at home. For similar information to this article subscribe to his FREE Newsletter by sending a blank email to homerecording@uncleslinky.co.uk
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