When taking about music, high fidelity, people often use the term good sound / “sounding good” about equipment and speakers. 

But what do we mean by this term.  I think it is very important to distinguish between two ways of perception.

1. 1)Personal taste, the subjective perception of what one actually like
   

2. 2)Pure high fidelity in the sense that your equipment is made to reproduce the source as precise as possible.
   

These two ways of understanding HiFi equipment is often not the same. And no way is better than the other, but it is very important to align the points of view when discussing audio and high fidelity. It makes absolutely no sense to mix up these two points of view.

To claim that a e.g. clock-radio sound good in the ways of hi-fi is crap, but some music is more appealing when played with a lot of colouring.

High Fidelity

When looking up in a dictionary high fidelity is defined as :

a )Sound reproduction equipment that reproduces sound as near to the original sound as possible.

b) The electronic reproduction of sound, especially from broadcast or recorded sources, with minimal distortion.

Distortion is the keyword, every part of an audio chain creates some kind of distortion. I will on this site try to describe the many different kind of distortion, that influences on the reproduction of audio, with audio examples to clarify the nature of all the distortion parameters