"Low A" refers to a specific musical note that is one octave below the standard A4 note, which is commonly used as a tuning reference. In the scientific pitch notation system, it is designated as A2. This note has a frequency of 110 Hz and is often used in various musical contexts, including orchestras and bands. In terms of instruments, low A can be played on several, such as the bassoon, trombone, and tuba. It is significant in many musical compositions, particularly in genres like classical and jazz, where deeper tones add richness and depth to the overall sound.