Shure KSM 26 into an Alesis 16-channel mixed into Delta 66 sound card. I've had a couple of experiences where a vocalist really goes for a note. The vu meter isn't getting into the red, yet I'm still getting some noticeable distortion.

Is the vocalist possibly just overpowering the mic? These would be inexperienced singers who don't know how to "work" a mic just yet.

Should I activate the pad on the mic?

Could I possibly be overdriving the built-in preamps in my Alesis board?

In short, my question is...

"What the hell?"