Baroque music presents elements that distinguish it from other genres. For example, Baroque music used the basso continuo, a system that employed two instrumentalists for accompaniment. One instrumentalist played the bass line like a cello or bassoon, while the other filled in the harmony on a chorded instrument, which was usually a harpsichord, organ, or lute. Baroque music was more simplistic than any other genre at that time because it was based on a single line melody and had less complex harmony. The major-minor tonality, a system of seven tones built on a tonic, is the result. The major-minor tonality has impacted the music industry by shaping musical structure and expanding forms of instrumental music to a level never before experienced. This led to a significant technical advancement called equal temperament, which was a tuning system in which each pair of adjacent notes had an identical frequency ratio. Dissonant chords were used more freely by Baroque musicians for their emotional intensity and color. The Baroque musical style also included dramatic forte/piano contrasts and echo effects. As in the Renaissance era, Baroque composers used word painting, a technique where the music reflected the literal meaning of the song. By the end of the 17th century, an entire piece or movement was usually composed of a single affection, such as joy, anger, love, or fear, also known as the doctrine of affection. Exoticism quickly became a distinct part of Baroque