Rihanna lets music do the talking on new album

(Def Jam Recordings)

Pop star Rihanna flaunted a blonde look Thursday to present new album "Rated R" but let the music speak for itself, refusing to answer any questions on ex-boyfriend Chris Brown who assaulted her in February.

The 21-year-old Rihanna, now on her fourth album in four years, explained the darker, edgier sound was the result of "venting" in the studio, "I got all my emotions out" she said, "and you hear it in the album".

R&B star Brown was sentenced to five years of probation and 180 days of community labour in August after pleading guilty to charges stemming from his brutal late-night attack in Los Angeles on the eve of the Grammy Awards.

"Each album is a reflection of who you are at that point in your life" Rihanna explained, and said that "at times" she felt "dark".

Her second track, Wait Your Turn, alludes to the relationship, as Rihanna sings in metallic, deep vocals: "I may be dumb but I'm not stupid... Let go, he's not the one".

Covering half her face on the album cover shot was "just about mystery", if "you show both eyes then you're vulnerable - here I'm very guarded".

"R Rated" seems to have had a cathartic effect on the Barbados-born star. Explaining her new look, she said she "heard blondes have more fun".

The 13-track album includes a heavy metal collaboration with ex-Guns N' Roses guitarist Slash on "Rockstar 101".

Justin Timberlake contributes again, this time writing the musically richer "Cold Case Love", which includes violins, piano and more emphasis on Rihanna's powerful vocal range.

"Rated R" is out on November 23 whilst first single "Russian Roulette" is already on general release. Rihanna announced she would be touring next spring.