Answer:
Absolute Threshold
Step-by-step explanation:
An absolute threshold is the smallest level of stimulus that can be detected, usually defined as at least half the time.
The term is often used in neuroscience and experimental research and can be applied to any stimulus that can be detected by the human senses including sound, touch, taste, sight, and smell.
In this scenario, the human sense used is the sense of sound, so you telling your neighbor to the volume down until you can not hear it simply means he should lower it below your absolute threshold for hearing, since any sound above the absolute threshold of your hearing would cause a sensation in your ears.