The Shumba Youth Marimba Ensemble performs  at the Santa Monica Pier on Friday, April 13, 2007, during their Southern California tour. The youth that make up Shumba range in age from 9 to 15 and hail from Seatle Washington. The Shumba youth ensemble usually plays using eight marimbas--three sopranos, three tenors, a baritone, and a bass--and hoshos, or gourd shakers. The marimbas are hand-crafted xylophones made from various hardwoods. The keys are fine-tuned to reflect the tones played in African societies. Each key sits above a resonator with a vibrating membrane to amplify the sound and add a unique "buzz" to the music.