inaudible

adj.

听不见的；

1. She spoke in an almost inaudible whisper.
   她悄声说话，令人几乎听不见。
2. The whistle was inaudible to the human ear.
   这种啸声人耳听不到。

The gleaning attacks of the northern long-eared bat, Myotis septentrionalis, are relatively inaudible to moths.
Anti-copy system utilizing audible and inaudible protection signals
The echolocation calls of the spotted bat Euderma maculatum are relatively inaudible to moths
Hearing impairment in congenital diaphragmatic hernia: the inaudible and noiseless foot of time
Inaudible high-frequency sounds affect brain activity: hypersonic effect.
Robust and Inaudible Multi-echo Audio Watermarking
Robust and Inaudible Multi-echo Audio Watermarking
Low-Performing Students and Teaching Fractions for Understanding: An Interactional Analysis
Context-Aware Computing with Sound
Remarks Iran, Sudan, and Other Matters