A novel's voice is something like a singer's -- think of singers like Mick Jagger and Bob Dylan, who have no musical training but are instantly recognizable. When people pick up a Rolling Stones record, it's because they want access to that distinctive quality. They know that voice, they love that voice, and something in them connects profoundly with it. Well, it's the same way with books.
It's well worth the time it takes to experiment with your voice for a novel. Once you've got the voice right, your novel will seem to "write itself."