Re: Drum Mics
I am not familiar with the SM91, as to it's sound pressure level capabilities. To reduce room acoustics that may bleed into the mic, place the mic about two inches from the batter head. In doing so you can reduce the mic level to a lower setting and thus reduce the unwanted sounds.
I have had good results with this mic placement regardless of type or quality. You can place the mic inside the drum on a foam pad to negate any vibration and aim the head of the mic directly at the point of impact of the beater.