Here's how you might use the word:
* "The general addressed the troops with a stentorian voice, his words echoing across the battlefield."
* "The teacher's stentorian reprimands were enough to silence the entire classroom."
* "The singer's stentorian voice filled the concert hall with a rich, powerful sound."
Essentially, a stentorian voice is one that commands attention and is hard to ignore due to its sheer volume and force.