The broad concept of "loose fragrance" is a special term, which refers to the natural charm that people get when listening to music, which is relaxed and smooth and full of the unique timbres of different instruments. Specifically, the word "loose" means not to make people feel tight and restless. The word "Xiang" means that when people listen to music, just as they appreciate the beautiful appearance of various flowers in a hundred gardens, they can appreciate the wonderful sounds of various musical instruments with different characteristics in the process of playing. In this way, it is easy for people to find an acceptable reference benchmark for judging whether the sound reproduced by a specific audio has a "loose fragrance" and whether it has a "loose fragrance". Obviously, noisy, loud or discordant sounds do not meet the requirements of "loose fragrance". People can feel the sounds of "looseness" and "fragrance", which are mostly the music sounds created by various musical instruments in people's long-term practical experience, which are artificially created by human auditory response. Generally speaking, all kinds of famous songs played by world-recognized famous bands can be used as a reference for "Songxiang". Those who can't afford to listen to the concerts played by these famous bands can also listen to their live performances at the concerts played by domestic professional bands, so as to establish the starting benchmark for identifying "loose fragrance" in their own feelings and experiences. Everyone will become the correct discriminator of "Songxiang" as long as they really listen and compare repeatedly.