We can download a digital file from anywhere in the world and it will sound the same regardless of where it came from or how it got to us.
Yet, once it safely arrives, delivering it even a few feet through different cables sounds different.
How could that be?
Is it possible that there's more going on than meets the eye? (or the ear?)
Imagine for a moment a faraway view of transportation. You pick the medium: car, train, or plane. Passengers line up at the input of the transportation system and arrive at their destination at its output.
Just like our digital signal.
If we look closely we might discover that not every traveler's trip was the same. Some went first class where it's quiet while others flew coach.
The point of this highly stretched analogy is simple. It is true that digital audio can be sent around the world without changing one bit. But get it close to our systems and other factors enter the picture. Factors such as radiated noise, power supply and ground changes specific to the local system.
Travelers all wind up where they were intended to go but not all have the same experience.
