Function of audio power amplifier

What role does audio amplifier and operational amplifier play in amplifier? There are two kinds of audio amplifiers, one is an operational amplifier dedicated to audio amplification, which has better performance in the audio range ( Mainly frequency response characteristics and distortion characteristics, good audio amplifier these two characteristics are very good), Generally used for the front amplification level of sound; The other is the audio power amplifier, which is the power amplifier circuit, which is used for the driving level of the sound, which can drive the speaker or sound with relatively high power to make a sound. Operational amplifier is a general term for integrated amplifier circuits, and its concept range is higher than that of audio amplifier (Specifically, an audio amplifier for pre-amplification) Large, and has a larger application range, its frequency application range is far greater than the audio amplifier, down to DC, high can reach several hundred M or even G Hz. Simply put, the audio amplifier is a special operational amplifier. In the audio circuit, both of these are used for the front amplification of the signal, so that the voltage of the audio signal is raised, so that the rear stage is used for power amplification ( The current amplification capability of the power amplifier circuit is very strong, but the voltage amplification capability is usually weak). From the use effect, the special audio amplification circuit has better performance on audio amplification than the general operational amplifier.