Rachelle Ferrell's low and slow-speaking voice belies her six-octave vocal range, a fact that lends itself comfortably to not only her urban pop sound, but also to gospel, jazz and even classical music.

Fans and newcomers to her work can hear her perform as she accompanies herself on piano at Blues Alley this weekend through Sunday night. And if she cares to treat her audiences, they will hear her trademark whistle register (the highest register of the human voice found above the modal and falsetto range), which she calls "Minnie Riperton-like wailing."

While Ferrell's song selections are always a surprise, her approach to each one is carefully studied and methodical. Long piano introductions segue into thoughtful phrasing.

"Some people sing songs like they wear clothing, they put it on and take it off," she said in the biographical notes accompanying "First Instrument," her 1994 release. "But when one performs four sets a night, six nights a week, that experience affords you the opportunity to present the song from the inside out, to express its essence. In this way, a singer expresses the song in the spirit in which it was written. The songwriter translates emotions into words. The singer's job is to translate the words back into emotion."

Rachelle Ferrell
Where: Blues Alley, 1073 Wisconsin Ave. NW
When: 8 and 10 p.m. Friday, Saturday and Sunday
Info: $60; 202-337-4141; bluesalley.com

Ferrell, a composer, lyricist, arranger, musician and vocalist, learned her craft studying and working with the best contemporary performers on the scene today. Both a violinist and a pianist from a very early age, she entered Berklee College of Music in Boston to study composition and arranging. Her classmates there included Branford Marsalis and Kevin Eubanks. She sang backup for performers such as Vanessa Williams, Patti LaBelle, Lou Rawls and George Duke.

On the album "First Instrument" (released in 1990 in Japan only and 1994 in the U.S.), her renditions of pop standards included Sam Cooke's "You Send Me" and Cole Porter's "What Is This Thing Called Love." Along with her 1992 U.S. debut album, she wowed festivalgoers for four consecutive years at the Montreux Jazz Festival. In an effort to keep from being pigeonholed in a specific genre, and to find a unique identity to her sound, Ferrell released her album of original tunes, aptly titled "Individuality," which showcased her incomparable skill as a songwriter who can also sing while accompanying herself at the piano.

Her loyalty to her fans is paramount to her continued success, as evidenced in a tweet awhile back where she wrote simply, "I love you all. You nourish me like vitamins."