Gregorian chant

Recently I had the opportunity to work with gregorian chant for the first time in my career. It became an incredibly rewarding and interesting process, partly because compared to most other music the framework is at first sight very restricted: It's a single line sung in unison in two or three different pitches with no tempi changes. However this opens up to a completely new world with an immense depth of subtle variation in sound (timbre) and phrasing.