Gregory Tristan "Tris" Imboden is an American rock and jazz drummer. As a performer, he has been in studio sessions and on tour with some of the most notable and highest-selling musicians of all time. He was the drummer for the multi-platinum band Chicago from 1990 to 2018. He is a multi-platinum selling artist. As an educator, he has been a drum clinician and author of tutorial materials.

Daniel Peter Seraphine is an American drummer, record producer, theatrical producer, and film producer. He is best known as the original drummer and a founding member of the rock band Chicago, a tenure which lasted from February 1967 to May 1990.