Flute Duet Flute - Level 4 - Digital Download SKU: A0.1133896 By David Mason. By Sergei Rachmaninoff. Arranged by David Mason. Classical,Multicultural,Romantic Period,World. Score. 14 pages. David D Mason #734016. Published by David D Mason (A0.1133896). I have arranged Rachmaninoff's Vocalise for Flute Duet with Piano accompaniment. Both Flute parts are about the same standard. This is the final piece in Rachmaninoff's 14 pieces or romances.