Exercise 39 introduces the most difficult of the triplet types, the quarter note triplet. The counting and placement of the quarter note triplet is difficult and takes time to master.
If you’re having difficulty hearing and placing the quarter note triplet, the following simple exercise can help:
Play continuous eighth note triplets over a bass drum pulse and either accent (play the note louder) the right hand heavily, or play the sticking between a very loud sound (right hand) and a very soft sound (left hand). The right hand pulse will be quarter note triplets.