Recently I have been working with some students on playing metric modulations between 4/4 and 6/8 time signatures where the quarter note is equal to a dotted eighth note. This is used very commonly in Latin, Afro Cuban, African, and many other types of music.
In these exercises I have kept the bass drum part as the common denominator between both time signatures. This means the bass drum does not change as you move between all of these patterns. What does change is the feel of 8th or 16th notes in the hands in the 4/4 to 8th or 16th note triplets in the hands (which feels slower) for the 6/8.
Each pattern should be repeated at least 2 or 4 times before moving to the next. The first pattern is just hat and bass drum to get used to the change to triplets against the bass drum. The second line is a simple pop/rock groove that goes to a basic 6 over 4 feel. The third line is using both hands on the hi-hat.
The last two are more complex and use some “world music” grooves. The first of the two starts with a simplified Soca feel and goes to an Afro Cuban vibe. The last one starts with a Latin influenced groove and goes to an African influenced 6 over 4 vibe.
These are just a few simple examples to help you get comfortable with this very common metric modulation. Be creative and create your own 4 to 6 over 4 modulations. Enjoy your practice time!