A fiction writer has a personality, a style, that carries across books. But the voice in a particular piece of writing may differ from others by the same author depending on the point of view. Which is why I have two different items on my checklist. The appropriate one for the work will apply.
☐ If using Deep POV, the narrative voice reflects the education, culture, and personality of the character.
I am educated and have a rather large vocabulary. I’ve even been known to stump my critique partners with words they were unfamiliar with. But if I write a story in Deep POV, and the POV character is uneducated and has a limited vocabulary, I have to curb my personal style and get in character, as an actor would. On the page, I have to play the part of the POV character.
My natural inclination might be to write a scene this way:
Slider moved slowly up the sculptured staircase. Balusters and banister of white Carrara marble lined the gray steps that showed beyond the edges of the threadbare burgundy carpet.
Slider is an artist, so he notices shapes and has the vocabulary to identify the parts and materials. If the scene were in someone else’s POV, it would have to be written differently:
Hazel moved slowly up a staircase that looked like something from a movie. A ratty, dark-red carpet ran down the middle of the gray steps.
Diction, sentence structure, the kinds of things people notice, the metaphors they use and the comparisons they make will all depend on character. If you have multiple viewpoint characters in your story, the voice will change from one section to another depending on who currently has the point of view.
☐ In omniscient POV, the narrator should have a distinctive voice.
What I mean by this second item is that the narrator’s voice should be different from that of the characters. An excellent place to see this at work is in A Christmas Carol by Charles Dickens. I love to use this as an example because you can get it for free in e-book form, and it’s a quick read. Furthermore, this is a great example because the voice of the narrator in this story is unlike the voice Dickens uses in his other works. I discussed this earlier at The difference between your voice and the character’s voice.
The important thing to remember about an omniscient narrator is that although he is not a character in the story, he should have a distinct persona, so he’s distinguished from the characters. Giving the narrator a persona helps you avoid “generic narrator voice,” in which the narrative carries no personality at all. How much this persona does or does not reflect your personal voice is a stylistic choice that’s entirely up to you.