Microphone categories can also be based on polar patterns (Directionality) of capsules.
Polar patter of capsules in microphones is nothing but an area around the microphone (or capsule to be more precise) from where it picks up the sound most and rejects from other areas. Tighter the pattern lesser the possibility of feedback. Look at the figures to give you an understanding of what each pattern looks like. Both Dynamic microphone and Condenser microphones come in many polar patterns. Also many microphones have switchable polar patterns. Ribbons are usually bidirectional.
(1) Omnidirectional Microphones — These are microphones that pickup sound from all directions around themselves equally. These are generally a bad choice in Masajid for stand / dynamic microphones as they are prone to feedback issues more than others. If these are used then sound from speakers can get into this type of microphone easily forming an infinite feedback loop. It is better to avoid them. Only works when you are recording an interview or discussing a subject where two or more people are sitting on a table with the microphone in the middle.
(2) cardioid Microphones — These pickup sound 180 degrees in front of the microphone and reject sound behind the mic. This is a decent choice.
(3) Hypercardioid / Supercardioid Microphones — They pickup sound mostly from front and very little from back and sides. These are the best choices and have least feedback issues. They reject ambient / room noises the most and we have had best success with them in all the Masjid sound system installations we have done.
(4) Bidirectional Microphones — Best used in interviews when two people are facing each other and the microphone happens to be in between them. It is also called figure eight pattern. Not a good choice for Masjid PA system.
(5) Shotgun Microphones — mainly used for outdoors but you can use it indoors if Imam wants to be microphone free and you are creative and knowledgeable enough to handle the situation. Picks up sound straight in front of it up to like 6 feet or more and rejects from pretty much everything from the sides. Picks up little from the back. This type of microphone can be solution to all our Masjid microphone needs but have to be careful when using it.
Microphones can also be generally categorized as
Omnidirectional
Unidirectional (Cardioid, Hypercardioid, Supercardioid & Shotgun)
Bidirectional