Whitney Houston, at age 22 pop music's newest megastar, showed all the earmarks of a potentially great singer at the sold-out Merriweather Post Pavilion Saturday night. She displayed a spectacular vocal instrument: On a sizzling version of Michael Jackson's "Wanna Be Starting Something," she came down hard on the dance beats and glided up into the stratospheric reaches of her soprano without the slightest hint of strain. On ballads like "Hold Me," her rich, creamy tone supplied the romanticism often missing in the cliche'd lyrics.

Most importantly, Houston took full advantage of her voice with a marvelous sense of phrasing and dynamics. She reinvigorated her well-worn hit "Saving All My Love for You" with well-timed pauses and big payoffs. On the tag, she engaged Josh Harris in an improvised duet of inventive scat vocals and sax phrases. She reprised her numerous duets with her brother, Gary Garland, a strong, husky tenor.

The only major doubt surrounding Houston's career at this point is her questionable choice in material. She favors the schmaltziest of ballads and the most predictable of dance tunes, and her new material was no better than the slight songs from her first album. She sang new songs by Paul Jabara, Michael Masser and the "Dreamgirls" show, but her voice was always much stronger than the songs. Unless she wants to become a fluff artist who sings whatever will sell, Houston must seek out material that is as strong as her voice. Instead of hacks like Masser and Kashif, she should be working with songwriters like Luther Vandross, Daryl Hall, Jimmy Jam and Terry Lewis.