O8h7w
100+ Head-Fier
Very good description of how it works and the experiment to see it for oneself.
The key part is correctly identified by
and that is the scientific answer to the questionFTA: "When the impedance of the termination matches that of the cable, there is no reflection."
while the practical answer is of course to listen to Ableza:Knowing that reflections are very real things, how do we push them out of the equation w.r.t. audio use?
Purchase the correct cable rated at the correct impedance.
That was the easy part (for me), the part where I'm sure what's what. Now for the harder parts!
I don't know. If you use an RCA cable meant for line level audio it can be bad enough to stop it from working altogether, but I don't know whether this specific problem is even capable of introducing a less obvious degradation.do we even need to worry about it?
How would one determine that, without scientific instruments?
I'm not sure that reviewing or reiterating the theory helps determine whether the goal has been achieved. No matter what the goal is.Read a text on transmission line theory. If the source and the termination match the transmission line impedance, then max power transfer occurs, and SWR [standing wave ratio] is minimized. Not much of an issue for audio cables, as they are short considering the frequencies being transmitted.
If the goal is to check whether a cable is in spec, you'll need some sort of instrument. If the goal is to do the experiment and see that the theory is right... I'm not sure. I can devise a way to generate a short enough pulse, but I'm not sure if I can devise a way to detect the reflection. A fast oscilloscope is a hard-to-replace instrument!
If the goal is to stop worrying, listen to Ableza.
If the goal is to figure out if we should care at all about slight impedance mismatches in our digital cables, then by all means do review the theory and think about it, keeping in mind the receiver electronics and jitter reduction/isolation technologies in play. And please post an explanation for us all if you find a certain answer!