When you're searching for words that describe someone or something as having a powerful and rich voice, there are plenty of options to choose from. Some popular synonyms for "most full-voiced" include resonant, sonorous, robust, deep, and booming. These terms all convey a sense of volume and depth, indicating that the speaker or singer in question possesses a voice that is full-bodied and impressive. Other possible synonyms might include mellifluous (to suggest a smooth and pleasant tone), dulcet (to emphasize a sweet and soothing quality), or even thunderous (to suggest a voice that is awe-inspiring in its power and intensity).