The rustle of the poplar leaves about the house worried her, it sounded so like pattering raindrops, and the full, faraway roar of the gulf, to which she listened delightedly at other times, loving its strange, sonorous, haunting rhythm, now seemed like a prophecy of storm and disaster to a small maiden who particularly wanted a fine day.
There are no more uses of "sonorous" in the book.
Show samples from other sources
The candidate discussed weighty matters in rich, sonorous tones.
I prefer traditional sonorous chords to the dissonant chords with which she likes to experiment.