Should You Yell At Your Kids Quietly In Public? [POLL]

I was raised on a farm so I don't really know how to be quiet outside. So when I am outside with my kids I  have a hard time not yelling at them to behave when they are out of line. Last night my husband got after the boys and actually yelled and whispered at the same time. It was like a raised whisper with gritted teeth. I thought it was pretty amazing because you could tell that he was upset but he was very quiet. I didn't know this was possible.

It made me think that I should be yelling quietly at my kids more often than I actually "yell" at them. Part of me thinks that I can't tell them "no" or "stop that" without yelling. Is it possible to yell quietly and is it really necessary or should we continue how our mothers did and yell away?