Sub-bass sounds are the deep, low-register pitches below approximately 70 Hz[1] (C♯2 in scientific pitch notation) and extending downward to include the lowest frequency humans can hear, approximately 20 Hz (E0).
In this range, human hearing is less sensitive, so these notes tend to be felt more than heard.
20 Hz is considered the normal low-frequency limit of human hearing.
When pure sine waves are reproduced under ideal conditions and at very high decibels, a human listener will be able to identify tones as low as 12 Hz (G–1).
Particular genres such as house music, drum and bass and dubstep often feature a bassline that consists mainly of sub-bass frequencies.