Sub-bass

Sub-bass sounds are the deep, low-register pitches below approximately 70 Hz (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. The low E-string on a bass guitar is usually tuned to 41.2 Hz, while the lowest note on a standard piano is A at 27.5 Hz. Sound reinforcement systems and PA systems often use one or more subwoofer loudspeakers to amplify sounds in the sub-bass range. Sounds below sub-bass are infrasound.