If you hear the clarion call of the stage, it means you want to be an actor. Clarion means loud and clear, and a clarion call is a call to something that is hard to ignore.
A clarion is a medieval horn with a clear sound. Hard to ignore, but also pure and clear in tone. There's nothing shrill about a "clarion call." Martin Luther King Jr.'s clarion call for all races in the US to live together in peace and harmony has lived on after his death.