Resonant, sonorous, ringing, resounding, vibrant, orotund are applied to the sounds or tones of speech and music and mean conspicuously full and rich.
Resonant implies intensification or enrichment of tone by sympathetic vibration (as by the soundboard and body of a violin or by columns of air above and below the vocal cords in the larynx).
It applies especially to musical tones, but in more general use it is applicable to a sound (as of speech or a bird note) that seems more than naturally full and rich.
Sonorous implies a quality of tone or speech suggesting the reverberant sound elicited by striking some metals (as copper or brass) or some kinds of glass; it may apply to a voice that is high and clear or, more often, to one that is deep and rich, but loudness and fullness are usually clearly implied.
As applied to language or utterance as distinct from voice sonorous may suggest depth and richness, but is more likely to suggest an obscuring or the absence of real meaning by lush verbiage or florid presentation.
Ringing usually implies a sound made by or as if by a bell; the word suggests a vigorous, stirring quality.
Resounding applies not only to vocal or instrumental sounds but to any sound that seems to reecho or to awaken echoes. It usually implies the increase of sound by something that throws it back, but it may imply a loudness and fullness of sound that seem to call forth echoes.
Vibrant , when used of sounds or tones, suggests vibration but not necessarily resonance; rather it implies qualities of life, vigor, or strong feeling.
Orotund usually describes an acquired or an affected quality of speech. It implies fullness, roundness, and dignity of utterance which may be regarded either objectively or contemptuously.