susurrous \seh-SU-rehs\ (adjective) - Pertaining to a susurrus (whispering sound), having or similar to whispering or rustling sounds.
"When vacationing at the beach house, Linda always left the windows open, as she found the susurrous sound of the ocean extremely soothing."
From Latin susurrus "whisper;" onomatopoeic, that is, a sound imitation. Most languages have an onomatopoeic word for "whisper" since it is a prominent sound. The Latin word has more whispering sounds [s] than our native Germanic "whisper" and, perhaps, conveys the sense better as a result. If you don't like "susurrous" you may also use "susurrant" as the adjective. The verb is susurrate "make a whispering, rustling sound" with its own family: "susurration," "susurrating," "susurrational," etc.