Joni Mitchell started smoking at age nine. “Everyone should be forced to smoke,” she told biographer Michelle Mercer, citing cigarettes as “a focusing drug.” Perhaps as a result, Mitchell’s voice appears to gradually drop an entire octave over the course of her career, and it is fun to compare the pristine, bell-like instrument heard in early footage to the husky contralto that steers Travelogue, a double CD comprising orchestral arrangements of some of her greatest hits. In contrast to 2000’s Both Sides Now, which found Mitchell covering her favorite songs in this manner (including two of her own), Travelogue is made up almost entirely of Mitchell’s own compositions, and though few of its versions match the power of the original readings, they reflect Mitchell’s view of her songs as living entities, subject to growth, expansion, and reassessment. Mitchell has never been confined by her arrangements: Compare the original recording of the tremulous “Woodstock” to the live versions found on 1974’s Miles Of Aisles (bouncy enough to be a roller skating jam) and 1980’s Shadows and Light (elastic, dreamlike), and then to the hypnotic, triumphal version heard here. Like Dylan, Mitchell’s ability to completely and fearlessly transform a song is remarkable. Throughout Travelogue, Mitchell sings behind the beat like Sinatra, emphasizes lines she seems especially pleased with, and generally allows herself to revel in the tonal colors of the orchestra. It is a credit to the evergreen nature of these songs that, more often than not, they transcend arrangements that are occasionally, perhaps expectedly, gauche. No song is done a particular disservice by the airbrush treatment, and a handful of dark horses — “Sex Kills,” “Slouching Toward Bethlehem” — are even improved by it. Mitchell’s voice, however, has begun to fail her: Years of unchecked indulgence in a certain “focusing drug” have left her sounding slightly weathered, weary. As a result, songs like “The Circle Game” and “Refuge Of The Roads” begin to inadvertently function as memento mori; imagine if Marianne Faithfull had ended Broken English with a cover of “My Way.”