Ostensibly a concept album that uses preexisting songs (mostly covers) to tell the story of a love affair — a commendably original idea — Both Sides Now teams Mitchell with an orchestra conducted by Vince Mendoza. Conceptually, it’s pretty neat: the album begins with songs dealing with initial attraction (the flirtatious puppy love of “You’re My Thrill,” the stirring “At Last”) and ends with a song of resignation and hard-earned wisdom (Mitchell’s own “Both Sides, Now”), bookending a suite of songs that ably reflects the emotional highs and lows in the life of a relationship. If only it were interesting to listen to. Mendoza’s mawkish arrangements leave Mitchell sounding sluggish and senescent; his dull, languorous renderings highlight not the beauty in these songs, but the banality. Lacking both the canny experimentalism and the kinetic exuberance that makes Mitchell’s original work so arresting, Both Sides Nowbecomes like an ornate theatrical prop: gussied up, but empty in the center.