Omnidirectional microphones receive signals coming from all directions. In contrast, unidirectional microphones only focus on receiving and transmitting signals coming from a certain direction.
Most musicians, sound engineers and podcasters are afraid to use omnidirectional mics in a multi-microphone setup due to its reputation of being prone to “leakage”. However, this “leakage” is what makes the sound picked up by omnidirectional mics more natural than unidirectional mics. For instance, in a roundtable discussion setting, using one or two omnidirectional mics in the middle to pick up the voices of the panelists will produce a more natural and smoother transition from one panelist to another. Using a unidirectional mic for each panelist in this situation will produce sudden pops and unnatural variations in loudness.
Omnidirectional mics have generally slower feedback buildup compared to unidirectional mics. This means that with omnidirectional mics, you are less likely to have ear-splitting feedback.
Omnidirectional mics are also less sensitive to wind, handling and pop noises (contrary to the common belief that they are more sensitive to everything!). Normally with unidirectional mics such as cardioid dynamic mics, you get sudden pops and clicks when you put the mic on the mic stand, and plosives (sounds that start with ‘p’ or ‘b’) are very prominent. These are less frequently encountered with omnidirectional mics.
However, omnidirectional mics have generally less precise channel separation. This may be a disadvantage when you have several mics on stage and you want them to focus on picking up only the sign