Each actor who auditioned for the role of Bruce Wayne in Batman Begins had to do their best Batman while wearing Val Kilmer's batsuit. Watch Christian Bale's, when he was going a bit lighter on the gravelly Batman voice.
Batman News posted a review of the Dark Knight Trilogy: Ultimate Collector’s Edition, which comes out this Tuesday. One of the tidbits they included in their review was that each of the actors had to audition as both Bruce Wayne and Batman (naturally) and that each actor had to wear the Kilmer costume while playing opposite Amy Adams as Rachel. They also posted Bale's audition:
Christian Bale auditions for Batman Begins in... by BatmanNewsCom
Although much noise is made in this segment about Bale creating different voices for Bruce Wayne and Batman, it's clear that the voice wasn't as extreme in his audition as it ended up being in the final films. The collection also includes Cillian Murphy's Batman audition, which prompted Christopher Nolan to consider him for the Scarecrow. Sadly, it sounds like we'll have to wait for that one.
The Dark Knight Trilogy: Ultimate Collector’s Edition review [Batman News via Comic Book Movie]