RMerlin, with respect, I have heard the effects of a simple speaker 'wire' change.
The noise floor was down at least 10Db, easily observable, even by my older ears and the room the musicians were playing in was eerily 'real' and changed with the recording being played back.
Good sound is not simply a sum of objective specifications. Other aspects can and do come into play. Just like two otherwise similarly spec'd routers can be observed to perform very differently, for example.
I have also heard digital cables have different sonic signatures (between dac and amp) - I did not imagine these differences.
What I appreciated most from my customer that allowed me to experience this first hand is that he would not make a snap decision if one component or the other was better. Only after a few weeks of listening would he make a purchase choice or not.
His words (paraphrasing) after almost two months with a new component, 'while the added detail was exciting, it was also aurally tiring over an extended listening session - and, real (acoustic) music doesn't tire you like this does'.
He was also quick to mention that on a different system, the added detail may lift the music up more naturally without the added harshness he experienced on his own setup.
It is always up to the buyer to beware. If something doesn't work better than what you have, that is what no questions asked return policies are for.
I know it may sound like voodoo to most people, saying that cables and digital wires affect sound, but this customer is not interested in simply having better equipment for its own sake; he is focused on matching as closely as possible the sound of the small, non amplified groups and solo artists that he enjoys listening to live, in his own home.