Mic distortion problem

[brandin]

I'm using a KSM 27 with a Presonus Blue Tube preamp.
I'm getting this crazy distortion when I really sing loud through the mic.
The gain and level is not peaking out, it just sometimes wants to distort at certain volumes of singing.

Any advice?

Thanks

[LeGato]

Sounds like you might experiencing what is sometimes called "proximity effect", also known as singing too hard too close to the mic. Have the singer pull back away from the mic as they are singing harder... Slight compression on the vox helps too.