 When the concerto is performed , according to Svoboda , instruments on stage are separated into three contrasting sections : the solo marimba , the quintet , and the remainder of the orchestra . The quintet is placed near the conductor and solo marimba , " which is the prominent voice of this uncommon ensemble " . The composition contains several instances where the quintet plays for extended periods , referred to as " islands " by Svoboda , which create " concerto grosso @-@ like interplay " with the orchestra . 
