Too vague to say. What is the room like and type of music? Acapella or accompanied? If the environment is sub par then a dynamic microphone is often the ticket. A pair of SM57's is a good option then or a single ribbon with a pair of voices on either side of the mic.

MillhousePro, post: 399059 wrote: What is the best mic to use for recording a vocal group of 3-4 people at one time. Some say uni-directional and some say omni-directional. please Help. Thanks!

For recording a vocal group like that you should be thinking of either a stereo mic or a pair of mono mics set up as a stereo pair. That implies directionality in the individual microphone responses (e.g. cardioid). Recording in stereo this way means that the singers would have to be arranged in an arc of 90 - 120 degrees. Although there is a technique that uses spaced omnidirectional mics, it's not best suited for the purpose you describe. Jack mentioned arranging the performers two each side of a microphone that had a figure-of-eight response, and, under appropriate conditions, this could work well, as could a pair of crossed fig-8 mics with one performer per microphone face to give a two-channel (but not directly stereo) result.

You don't give an indication of budget, but by way of example, have a look at the [="http://www.rodemic.com/mics/nt4"]Rode NT4[/]="http://www.rodemic…"]Rode NT4[/] as a stereo mic. Most mics of this professional type need an audio interface to connect to a computer, and for stereo recording, you would need an interface that has at least two identical microphone inputs.

The other approach is to consider a small solid-state recorder that has built-in microphones. The [[url=http://="http://www.zoom.co…"]Zoom H4N[/]="http://www.zoom.co…"]Zoom H4N[/] is a popular and good-performing model for this sort of work. As a further frill but not a toy, Rode has just introduced the [[url=http://[/URL]="http://www.ixymic.c…"]iXY[/]="http://www.ixymic.c…"]iXY[/], a stereo mic that plugs into an Apple iPhone or iPad.

However, as Jack indicated, you need to take into account the type of music, the purpose of making the recording, and the acoustics of the room in which you will be recording. Come back with more information and we can help further.