Personally, it is a noun that is actually "arranger" and "orchestrator" arranger: it is to expand the expression form of the music without affecting the main melody and content of the original music. In modern music, especially in pop music, the composer and arranger are often two people, because many composers only have the grasp and inspiration of the melody, and the arranger has more skills in how to embody the melody. Simply put, the composer gave the skeleton, while the arranger gave the flesh and blood. Orchestrator: Orchestrator is the process of matching a main melody with the total score of multi-voice accompaniment. This is a complicated musical process. Orchestration is one of the components of composition. Refers to the coordination of various instruments in instrumental ensemble. Its main points are as follows: 1. Performance of various musical instruments; 2. The timbre contrast and coordination effect of various musical instruments; 3, the original sound of the music is unified. The orchestration is not only used for initial writing, but also often used for ready-made music orchestration, such as adapting piano music and ensemble music into orchestral music. The main musical instruments in the orchestration are flute, electronic organ (generally two), violin (at least two, one violin is responsible for long tone and one violin is responsible for some melody and polyphony), trumpet, trombone, guitar, bass and drum.