"melodious voice" is correct and usable in written English.
You could use it to describe something with a pleasant sound, such as: "She spoke in a melodious voice that was soothing and calming."
His deep, melodious voice completed the effect: commanding.
"Just to say they enjoy hearing me speak," she said, her melodious voice beginning to crack.
(Even when he's rapping, he's singing, in a flat, loosely melodious voice).
But Ms. Nugent hesitates, her melodious voice dropping low on the telephone.
He could speak for hours, without notes, and his deep, melodious voice soothed even as his words often provoked.
"I had no one to welcome me to this world of freedom," Ms. Weems read in her husky, melodious voice.
Thickheads have heavy-looking, seemingly neckless foreparts and are named alternatively for their loud, melodious voices.
Some species just have a thing for shiny feathers or neon stripes, elaborate nests or melodious voices.
All species have high, thin, melodious voices; in courtship the male may sing in the sky or audibly clap his wings aloft.
I was blessed with my father's golden tones and melodious speaking voice.
He had a melodious speaking voice: "We could all use some skills, right?
