The Ottawa Chamberfest will celebrate its 30th birthday this summer with more than 60 concerts and events over two weeks, featuring some of Canada’s brightest stars, including Angela Hewitt and Marc-André Hamelin. Yet, big names aren’t the focus at Chamberfest 30. This year’s theme is “championing.” Artistic Director Carissa Klopoushak has encouraged performers to champion something they care about in their programs—be it a social cause, a little-known composer, or an emerging artist. This directive is the reason Hewitt will share the stage with rising-star-of-the-piano-world Carter Johnson, and Arion Baroque Orchestra will explore gender in a gender-bent concert of Handel…