Acclaimed by critics as one of this generation's great voices, Siberian baritone Dimitri Hvorostovsky (that's pronounced ''Var-as-toff-ski'') sounds almost too good to be true. Just two years after winning his first international vocal competition in Wales, the silver-haired, 29-year-old heartthrob has accelerated so meteorically he's been dubbed ''the Siberian Express.'' Now in the middle of his third American solo tour, which ends Nov. 1 in Washington, D.C., he's just released a new recording of Cavalleria Rusticana with Jessye Norman, and his solo album, Russian Romances, a moody collection of songs by Tchaikovsky and Rachmaninoff, recently bumped Vladimir Horowitz from the No. 2 spot on the classical charts. Doleful music, says the soulful baritone, is his forte. ''Sadness, Russian sadness it's my normal emotion.''
A self-admitted former ''hooligan'' and ladies' man (''When I was young, I had a very big collection of girlfriends''), Hvorostovsky lives in Moscow with his wife of two years, former ballerina Svetlana Alexandrovna, 32. His musical triumphs, he says, have had a bracing effect. ''When growing up (in Krasnoyarsk), my success was a romantic dream. Now it's a reality. It's here. It's a reality I must face like dying.''