The mixed roll is one of the most popular rolls used in bluegrass banjo playing and is relatively easy. It’s similar to the double thumb
roll and it can be broken down to the first 4 notes in the first example below. The big difference here is that you now use your index finger for the second note of the
four-note pattern (TITM instead of TMTM). Logically, by using three fingers (thumb, index, and middle) you should be able to play faster than with double thumbing, in which
you only use two fingers (thumb and middle).
Since the second note in this pattern uses the 2nd string, the mixed roll will only be used when the first note of
the pattern (usually the melody) is on the 3rd or 4th string. We will still use double thumbing when the melody is on the 2nd string.