The influence of the sound source itself is actually very large. The sound source quality depends on the music file format and compression ratio. At present, the most mainstream music formats are of course MP3 and wma, and almost all MP3 players are compatible with these two formats. MP3 should be regarded as the lossy compressed digital audio format with the largest number of users at present. The bit compression ratio of MP3 files we usually listen to is 128kbps, and the compression ratio is about 1: 10. The file size is generally only 4M, which achieves a relatively balanced position in volume and sound quality. However, the compression rate of songs we download from the internet is often very low, often only 96kbps or even lower, and the effect is not very satisfactory. This is the practice that the website deliberately reduces the compression rate because of download speed and copyright problems. The best way to enjoy the real sound quality is to find a cd with better quality and compress it yourself. Generally speaking, MP3 files with compression ratio of 192kbps have relatively good sound quality. When playing with a good MP3 player, the effect is very close to that of MD. If it is compressed to 320kbps, the sound quality is very close to that of a cd player, which is difficult for ordinary people to distinguish.