Jan. 14 Naturally 7 Holland Center, 1200 Douglas St. 8 p.m., $19-$50, 345.0606 omahaperformingarts.org The voice as instrument is a concept used by all vocalists. But the way Naturally 7 uses vocals to replicate actual instruments is astounding. The a capella crew of seven came together in 1999 when brothers Roger and Warren Thomas joined with five other master singers. Using the “vocal play” technique the ensemble mimics the sounds of drums, guitars, flutes, horns and other instruments, but every sound uttered comes from the septet’s voices. This unique approach results in gorgeous harmonies and an overall feel that somehow merges to appeal to fans of both Rahzel and Boyz II Men. Naturally 7 appears as part of Omaha Performing Arts’ Popular Series.