The PZM is normally a flat piece of plastic with a place to plug in a cable that can be mounted to a flat surface such as the lid of a grand piano, or a wall. Sound vibrations are picked up from the host structure and converted to a signal. Now that we've covered the two basic types of microphones it's time to move on to response patterns. The response pattern, sometimes referred to as polar pattern, or pick up pattern, is the direction and shape of the area around the microphone that it will pick up. Some microphones will pick up a signal directly in front of them and reject a signal from behind while others may pick up everything in a 360 radius.
Some microphones even have a selector switch to change, or alter the response pattern.
Example of response patterns. Omnidirectional will pick up equally in all directions making it useful for group vocals, or room ambience, but not very good for isolating a single instrument Bidirectional, or figure 8, will pick up on opposite sides equally making it good for capturing group vocals on either side, or in a situation where sound from the sides should be rejected. Cardioid, or directional, is named for it's heart shaped response pattern and are good for vocals, or anytime you want to isolate a single instrument. Hypercardioid has a tighter front response while having a slight pick up to the rear, which is good for miking an instrument like a guitar amp where you might want to pick up some of the room ambience from behind. The supercardioid is just another variation of the cardioid family that has a narrower rear response while maintaining a much broader front response.