The purpose of a ground bass is to provide a sense of stability and continuity throughout a composition, often acting as a unifying element that ties together different sections or movements. It can also serve as a point of reference for other instruments, helping to establish the overall tonality and harmonic structure of the music.
In its simplest form, a ground bass might consist of a single note or chord repeated over and over again. However, it can also be more complex, featuring variations in rhythm, melody, and harmony.
The ground bass technique has been used in various musical genres and periods throughout history, from early Baroque music to contemporary jazz. It is particularly common in traditional forms such as the passacaglia and chaconne, where the ground bass provides the underlying structure for elaborate variations.
In the case of a ground bass guitar, the guitarist would typically play the repeating pattern of notes in the lower register of the instrument, while other instruments (such as a melody instrument or a countermelody) play different musical lines above it.