Sound reinforcement systems and PA systems often use one or more subwoofer loudspeakers to amplify sounds in the sub-bass range. 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.
In this range, human hearing is less sensitive, so these notes tend to be felt more than heard. Sub-bass sounds are the deep, low-register pitches below approximately 60 Hz (C 2 in scientific pitch notation) and extending downward to include the lowest frequency humans can hear, approximately 20 Hz (E 0). The double bass is the sub-bass instrument of the orchestral strings family, as it produces the pitches in the lowest register for this family. Double bass player Vivien Garry playing a show in New York City in 1947.