What is good audio system? What is good sound? How to create good sound?

This may be the problem that the refitting stores of automobile audio need to discuss and pursue.

We know that the automobile audios have their own properties, for example, certain products are good at restoring human voice, or the high frequency is very bright, or the interpretation of large dynamic is in place. However, whether the sound systems refitted by every refitting store are same after we selecting these products? No. The arrangement of equipment, treatment of refitting process and test of system sound are various due to the refitting. The quality of system sound depends on “technology”.