There's a part in The Dark Knight Rises that's stumped me, where it sounds like Bane's voice is suddenly and significantly changed -- beyond his normal post-production mask-speak. It sticks out so starkly, I can't help but feel that it was intentional, for effect.
When I saw it in theaters, I initially thought it was perhaps an allusion to the "spirit" of Ra's speaking through Bane, or similarly, that perhaps it was the League of Shadows as a whole -- a legion of spirits speaking through the League of Shadows-"incarnate".
After the movie, when discovering that others hadn't heard or noticed it, I wondered if it was just coincidental, or perhaps just some fluctuation or mismatch of Bane's voice processing in post-production.
Where it is:
In the underground sewer scene, when Bane and Batman are fighting, listen to Bane's lines right after Batman throws the smoke bombs in front of Bane.
BANE: "Theatricality and deception, powerful agents to the uninitiated."
BANE: "...But we are initiated, aren't we, Bruce?"
BANE (voice change): "Members of the League of Shadows. And you betrayed us."* (emphasis mine)
BATMAN: "..."Us"? You were excommunicated... by a gang of psychopaths." (*See EDIT)
BANE: "I am the League of Shadows..." (switches to normal voice) "And I'm here to fulfill Ra's Al Ghul's destiny!"
It sounds so distinct to me, it sounds like a different actor's voice entirely.
Batman calls out Bane on his "altered"-voice statement where Bane infers that he's still in full fellowship with the League of Shadows. This could lend credence to Bane actually changing his voice as if it were the League speaking through him, like a legion, or as a spokesperson.
This could be an intentional alteration by Bane himself, or it could perhaps be an "audience-only" subtext or view -- subtly foreshadowing the coming resurgence and "reincarnation" of the League of Shadows through both Ra's' appearance and Talia's (eventual) unmasking.
It definitely doesn't sound like Ra's' voice (Liam Neeson), though, which could've made plausible sense (plot-wise) as a foreshadowing or reminder of Ra's' "eternal" nature. Although this voice change could similarly be alluding or foreshadowing to a wider scale of the League of Shadows as a whole (if intentional, of course).
After rereading and rewatching the scene, it's now my opinion that the voice change here very likely is intentional, whether in a "conscious" or "subconscious" theatrical vein.
I lean toward it being a subtle, subconscious form of directorial foreshadowing, where it's not intended for the audience to be consciously aware of or focused on it -- much like the similar "subconscious" foreshadowing of when we first see Miranda and Bruce meet (at the charity ball) --
Miranda enters the scene covering her face with a masquerade mask (alluding/foreshadowing her deception as "Talia"), as Bruce asks her, "Miss Tate, ...isn't it?" (she doesn't answer him, only puts down the mask):
What makes Bane's voice change seem too unlikely to be coincidental is that the pairing of the voice change coincides with the precise instance of his dialog where he no longer refers to himself as a singular individual, but rather, as multiple people, a group --
"Members of the League of Shadows.... you betrayed us"
And even Batman doesn't let this slip past unnoticed, calling Bane out on it --
"...'Us'? You were excommunicated..."
...Which Bane then responds by reversing his reference of himself as a singular individual rather than many -- while also coinciding with the "altered" voice suddenly disappearing into the shadows.
Hence, I think I'll put my money on this being a subtle, "unconscious" foreshadowing for the audience that the League of Shadows is still alive, that it's not just Bane acting solo.
Nevertheless, I'm going to try to reach out to someone involved in the production process, in the hopes of shedding some definitive light on this -- (just for fun, of course) :) I'll post back any information.