During introductory remarks before a concert by the Sphinx Virtuosi at Carnegie Hall on Tuesday evening, Rocco Landesman, chairman of the National Endowment for the Arts, said that less than 5 percent of players in American orchestras are black or Hispanic.  

 The Sphinx Organization in Detroit, founded in 1996 by the violinist Aaron P. Dworkin, hopes to expand that number and increase minority representation among performers, composers and audience members by providing instruments and free training to African-American and Hispanic students, among other programs. In a video shown at the end of the concert, Mr. Dworkin, who is biracial, discussed his own experiences of feeling isolated in the audience and onstage.

Winners of the organization’s annual competitions tour with the Virtuosi, a conductorless string ensemble. Some also form smaller groups, like the Catalyst Quartet, which was featured in Tuesday’s concert.
One highlight was an impassioned rendition, by Gabriel Cabezas, of “Perpetual Motion” from Coleridge-Taylor Perkinson’s “Lamentations” for solo cello. Mr. Cabezas, a student at the Curtis Institute in Philadelphia who won the senior division of the Sphinx Competition this year, was presented onstage with the Isaac Stern Award, offered annually to a particularly promising Sphinx prizewinner. (Stern, who died in 2001, taught several winners privately.)
The violinist Elena Urioste, the 2007 winner of the competition, played soulfully in “Primavera Porteña,” from Piazzolla’s “Four Seasons in Buenos Aires.” The Virtuosi were joined by the jazz trumpeter Irvin Mayfield for a sultry performance of “Autumn in New York” in an arrangement by James Lee III, based on a recording by Charlie Parker.