Cupping the Mic

It’s common to see pop singers cupping the mic with both hands. They do this to reduce external noise and to increase the mid-range and bass tone of the voice. The problem is that it only has a minimal effect of reducing other noises and it totally messes with the tone and volume. It’s also likely to make your sound engineer’s blood boil, and no one wants to have that happen during a gig. 

If you’re trying to produce a certain sound, you’ve rehearsed it, and your sound engineer and the band know what to expect, then anything goes, but if you’re looking for a clean reproduction of your voice, stick to a simple grip.