If a microphone picks up sound from all around in a 360 pattern it is called omnidirectional & we would plot its polar pattern like this. The symbol for an omnidirectional pick up pattern is the symbol on the left of the picture on the AKG micon the previous page - the circle.

0 is the front of the mic.
180 is the back of the mic.
90 & 270 are the sides of the mic.



A cardioid mic picks up sound from its front. It also picks up sound from its sides although less well & it is not sensitive to sound at all at the back. The diagram reflects this.

The Shure SM58 is an example of a cardioid mic. There are also a couple of variations of the cardioid pick up pattern these are called the HYPERCARDIOID & the SUPERCARDIOID. You can see these pick up patterns below.

hypercardioid supercardioid