Originally posted by Eric Buss:
I am no expert, but I thought the options for lav mics was omnidirectional, or unidirectional. In which case I have been told that Omni is better because it will pick up a voluteer's voice. Plus if you move around a lot on stage, omni also corrects for that... is this wrong? I am also in the market soon for a new lav. I think I am currently using an omni (I would have to check) and feedback has not been a problem...
Most "unidirectional" lav mikes are actually cardioid. Omnidirectional will pick up a volunteer's voice, if they speak loudly. But there should be no difference in the way an omnidirectional picks up in any position on the stage. This is more of a function of the kind of receiver you have. A true diversity receiver corrects for the position of the transmitter on stage.
Feedback is caused by the microphone picking up the sound coming from the speaker and running it back through the amplifier. There are electronic circuits that will eliminate this to some degree or another, but I still haven't found one that is 100% perfect.
Feedback will not be a problem with an omnidirectional mike if the microphone is not located in the area where the speakers are sending out sound waves. That is, if the speakers are in front of you, aiming towards the audience, rather than behind you. If you have monitor speakers on stage, aimed toward you, then they should be turned off or turned down to a low enough volume that they are not picked up by the microphone.
When I worked comedy clubs with my wireless units, I found that I could hear the speakers well enough without using the monitors, that I could tell what was going on with my music and with my speaking. So, I would instruct the sound man to turn off the monitors when I went onstage, because the mikes I had were omnidirectional.