Forget the Oscars. This is the best version.
(YouTube video: Jimmy Fallon, Idina Menzel and The Roots perform "Let It Go" on classroom instruments!)
The song as it appears in the film was undoubtedly assembled from
multiple takes and enhanced electronically- a necessity when you're
planning to exhibit it in huge IMAX venues with several thousands watts
of audio amplification.
(YouTube video: Idina Menzel performs "Let It Go" in "Frozen.")
Frankly, her Oscar performance wasn't her best... having John Travolta mangle her name didn't help. Think about it- you're following Bette Midler, you're the last musical performer of the night, singing what everyone expects to win the Oscar for Best Song, the live orchestra is in a recording studio over a mile away, and "Let It Go" (which its authors say was specifically written to be "Idina's Badass Song") is the Power Ballad from Hell, ranging from F3 to E♭5.
Go ahead... follow along...
(YouTube video: Let It Go arranged by Larry Moore)
Anyway, it was nice to see her actually enjoying herself with Fallon and The Roots.