sonorous

adj

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.”

   “The Oath is redacted ; pronounced aloud by President Bailly, — and indeed in such a sonorous tone, that the cloud of witnesses, even outdoors, hear it, and bellow response to it.”

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.”

   “For this reason the Italian opera seldom sinks into a poorness of language, but, amidst all the meanness and familiarity of the thoughts, has something beautiful and sonorous in the expression.”

   “There is nothing of the artificial Johnsonian balance in his style. It is as often marked by a pregnant brevity as by a sonorous amplitude.”

   “When the right-away was given, Driver Gibson would give a sonorous blast on Cardean's deep-toned hooter, and amid a flurry of swirling steam the train would move majestically out, with nearly half the city of Carlisle—or so it would appear—as onlookers on the platform.”

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

   “Vowels are more sonorous (acoustically powerful) than consonants, and so we perceive them as louder and lasting longer.”