Originally Posted by echoclerk
can the above explain what sort fo changes you get int eh sound when using a Bi-Directinoal or Omni Mic for say the Lead vocals?
in what instances would you use that over a Cardiod?
Omni has no proximity effect, so you get a more natural 'body' of sound that doesn't fluctuate as much with the singer moving. But then if the singer moves purposely this can be part of the sound in cardio or fig 8. Generally different mics in different rooms on different vocalists will give you different reasons for either, as stated above.
As to the last question: When it sounds better, i.e. closer to the sound in your head you're going for. Don't forget, the frequency plot tends to change when switching patterns too......try and see.