Audio is a technical term that has been used generally to describe sound-related devices and their functions in the audio range. All sounds that humans can hear are called audio, which may include noise, etc. After the sound is recorded, whether it is speaking, singing, or musical instruments, it can be processed by digital music software, or it can be made into a CD. At this time, all the sounds remain unchanged, because CDs are originally a type of audio files. And audio is just the sound stored in the computer. If there is a computer coupled with a corresponding audio card - that is, the sound card we often say, we can record all the sounds, and the acoustic characteristics of the sound, such as the level of the sound, can be stored in the form of computer hard disk files. Everyone admits that it is a digital age, and many people have made unremitting efforts to pursue excellent sound quality. With the advent of the digital age, it has become a consensus that digital signals are superior to analog signals. What is an analog signal? In fact, any sound we can hear transmitted through the audio line or microphone is a series of analog signals. The analog signal is what we can hear. The digital signal is to use a bunch of digital symbols (actually only binary 1s and 0s) to record the sound, instead of using physical means to save the signal (using ordinary tape recording is a physical method). We can't actually hear digital signals.