A character changes voice while in costume. It is usually part of an attempt to disguise themselves. The voice change may be done by themselves, or done via external means, such as a mask or helmet with built in voice modulator.
This is distinct from the more appearance-oriented Clark Kenting. This is an effective way to maintain a Secret Identity and it can also suggest a case of Secret Identity Identity if you consider that the person's two identities have totally different voices and mannerisms.
Compare Power Makes Your Voice Deep, when accessing your power (and, usually, disguising yourself in the process) grants you a different voice.
- Hei of Darker Than Black has his voice deepen when he goes from his persona as Li into his identity as the "Black Reaper". It's not for nothing they call him Chinese Electric Batman.
- Lelouch from Code Geass speaks with his regular teenager voice when in his civilian, Rich Idiot with No Day Job persona, but switches to a much deeper, booming (read: much more epic) voice when acting as the Rebel Leader Zero.
- All Might from My Hero Academia speaks in a booming and enthusiastic voice fit for a superhero; as civilian Toshinori Yagi, he sounds tired and deadpan. This has less to do with preserving a secret identity and more to do with keeping up his image as the tireless symbol of peace and justice.
- In Batman v Superman: Dawn of Justice, Batman uses an electronic voice modulator to alter his voice.
- The Dark Knight Trilogy
- The deepening of Bruce Wayne's voice when he puts on the Batman costume is taken Up to Eleven- he sounds like he's gargling with gravel. Oddly, he still does this even when he's talking to people as Batman who know his secret identity.
- He takes this to another level in Batman Begins where he has his normal Bruce Wayne voice, a raspy voice for talking to allies as Batman, and the gravel-gargling voice he uses when trying to scare the crap out of bad guys.
- In Green Lantern, Ryan Reynolds as Hal Jordan plays with this a bit - speaking in his dramatic superhero voice when trying to impress Carol Ferris as Green Lantern, but she soon sees through this.
Carol: I've seen you NAKED! Did you think I wouldn't recognize you because you covered up your cheekbones?!
- Iron Man: Stark's Iron Man armor's helmet makes his voice more mechanical.
- In On Her Majesty's Secret Service, in the scenes where Bond is impersonating an expert on heraldry George Lazenby is dubbed by the actor who played the real expert.
- Parodied in Spiderman Homecoming, where Peter Parker's suit (also made by Stark)'s "Enhanced Interrogation Mode" gives the bumbling teenager's voice a comically deep filter.
- Senator Palpatine/Darth Sidious in Star Wars. Palpatine loses the "normal" voice entirely after Mace Windu's attack, when he becomes Emperor.
- In the Batman television series, Bruce Wayne was put into a situation involving him Holding Both Sides of the Conversation. Since he's on a phoneline, it's just a simple matter of switching between his Batman voice and his Bruce voice.
- The Arrow himself uses a voice modulator that artificially deepens his voice that not only keeps people from recognizing his celebrity voice, but also works to intimidate thugs suddenly faced with a murderous and guttural archer.
- The Smallville version has this too.
- Sara Lance uses a voice modulator similar to the Arrow's to prevent people from identifying her as the Canary.
- The Flash (2014): Whenever Barry Allen needs to talk to his crush as the Flash, he vibrates his vocal cords at super speed so she won't be able to recognize his voice. His Evil Counterparts, Reverse Flash, Zoom, and Savitar all use this technique to alter their voices, but they end up deepening their voices so much that people mistake them for demons. (The Rival also does this, but itís less ominous-sounding, more akin to the Barry version.)
- Black Lightning: Pierce gives his voice a reverb effect when he's in the suit. Jennifer also mentions that his face "hurt to look at," further helping obscure his identity, though his face doesn't look any different to the audience.
- Hunter Street: When disguised as HoodieHead, Sophie has a vocal modulator to change her voice to be unrecognizable.
- In Choujinki Metalder, Tsurugi has a completely different voice actor for when heís transformed. In the final episode, itís a Bittersweet Ending where he loses his powers but canít return to his human form ever again, and Metalder speaking with the Tsurugi voice now really hammers it in.
- In Power Rangers, a few mystery Rangers have had deeper voices that disguised their secret identities. Actually, the first was the original Gold Ranger waaaay back in Zeo, who had a different voice actor when morphed.
- Kamen Rider Fourze does it better than any of the above, making for a hell of a Reveal: Youíd never guess from the deep growly voice of one of the Big Badís generals that heís actually a she and was right under the heroesí noses all along.
- In Batman: Arkham Knight, the titular Knight uses an electronic voice modulator to distort his normal voice. Given that Batman would recognize Jason's voice otherwise, it does its job well.
- BlazBlue: Hakumen wears a full-body armor and a deep, echoing voice courtesy of the armor. His voice is actually much softer, courtesy of him being an alternate timeline Jin Kisaragi.
- Done by two characters in The Legend of Heroes: Trails of Cold Steel: "C" wears a helmet that modulates his voice, disguising his true identity of Crow, and Thomas notably adopts a deeper, more serious tone when he drops his facade of being a carefree, lackadaisical teacher and reveals he's actually the Second Dominion of the Gralsritter.
- Ratchet & Clank
- In Ratchet & Clank: Going Commando, the Thief sounds like a digitally distorted man while wearing their costume, but she has a regular-sounding female voice once the costume is off.
- In Ratchet & Clank Future: A Crack In Time, at one point, Ratchet pretends to be Dr. Nefarious in order to use the laser in his space station to destroy his fleet of ships. This disguise, of course, comes with that character's voice.
- In Batman: The Animated Series, Batman has a lower, more serious voice than Bruce Wayne. The shift is far more subtle than in the Nolan films, but he seems to put it on whenever he puts the suit on, even when he's talking to people who know he is Bruce Wayne. However, from The New Batman Adventures onward in the DCAU, Bruce's voice shifted down to be the same as Batman's.
- Just like the original Batman, in Batman Beyond Terry's voice also changes in when he's in the bat-suit, though it's explained to be something the suit actually does somehow to help disguise his identity.
- Also from DCAU, the Batwoman in Batman: Mystery of the Batwoman has a voice unlike her real identity (that is, any one of the three). This overlaps with Cast as a Mask as the Batwoman has a voice actress that doesn't voice any of the other characters.
- In DuckTales, Fenton Crackshell is a nebbishy accountant with a voice to match, but when he puts on the Gizmo Duck costume, he becomes The Cape and starts talking in stock hero speak.
- Parodied by Buttercup in The Powerpuff Girls episode where they decide that they all need secret identities to be "real" superheroes. The "Mange" persona she adopts takes her Tomboyish Voice and makes it so raspy it's ridiculous.
- The Spectacular Spider-Man
- Quentin Beck is a fairly mild-mannered guy, and talks in a hammy faux-British accent when being Mysterio.
- The Green Goblin has a personality so different from his civilian identity that it is appropriately represented by giving the two separate voice actors. Interestingly, this version of the Goblin isn't a Split Personality.
- In the 1960s Spider-Man series, Spider-Man's speaking voice is about an octave deeper than Peter Parker's, even when there's no need for it (e.g., when he's talking to himself and there's nobody else around).
- In South Park, Kenny deepens his voice when dressed as Mysterion.