The intensity of this sound is below the auditory threshold.
Tips
usage
Technical psychology / physiology term - the minimum level at which a stimulus can be perceived. Often paired: 绝对阈限 (absolute threshold), 差别阈限 (difference threshold). Note 阈 is yù, not yuè.
memory
Both 阈 and 限 contain a boundary idea (阈 has 门 'gate'; 限 has 阝 'mound' + 艮 'limit'). Stack them and you get 'gate-limit' = threshold.
