Sonorous

adjective

1. Capable of giving out a deep, resonant sound.

   "The highlight of the hike was the sonorous cave, which produced a ringing echo from the hiker’s shouts."

2. Full of sound and rich, as in language or verse.

   "He was selected to give the opening speech thanks to his imposing, sonorous voice."

3. Wordy or grandiloquent.
4. Produced with a relatively open vocal tract and relatively little obstruction of airflow.