sound effects, etc., and discard the original car power amplifier. It outputs general-purpose optical fiber/coaxial sound signals in the format required by professional audio equipment, thereby completing the conversion of car-specific network data to professional audio data. In this way, the unprocessed original sound source can be obtained, and at the same time, an external high-quality sound source can be added to match with the retrofit aftermarket power amplifier (with digital DSP function, supporting common optical fiber/coaxial signals), thereby bringing a perfect sound modification effect.