The Christmas season rang in Downtown Crossing with a distinctive low note or, rather, 100 such low notes as just as many regional brass instrument players assembled for Boston’s annual TubaChristmas.

The tuba, sousaphone and euphonium players assembled dressed in their holiday best and surrounded by merry decorations to blow past Thanksgiving and into the Christmas season starting at noon on Saturday with a concert of classic holiday favorite tunes.

The annual tuba-tacular is the kickoff event for this year’s “Snowflake Crossing” that converts Boston’s downtown into a winter wonderland. Upcoming events include Thursday’s Christmas tree lighting on the Common; Dec. 7’s Singing Nuns as the Daughters of St. Paul’s Choir enchants the public; the downtown Holiday Market that the city describes as “a fantastic lineup of artisan vendors to offer their handcrafted products outside on Summer Street,” which started Friday and runs through Dec. 23; and free visits with Santa, which also started on Saturday.