One of the big issues of impedance matching besides the frequency problems and other issues is the transfer of signal.
Using a very simplistic example.
Using only voltage you have a ratio of transfer. So going from 10k to 10k you would have 50% transfer. Going from 1k to 10k would give you a 1 to 10 transfer ratio and so on. Generally, so you don't have current loading issues and voltage transfer issues, it is best to have a low impedance source to a very high impedance input.
Anything else is tone control to an extent and that is why interconnects make a bigger difference on some systems then others.
Using a very simplistic example.
Using only voltage you have a ratio of transfer. So going from 10k to 10k you would have 50% transfer. Going from 1k to 10k would give you a 1 to 10 transfer ratio and so on. Generally, so you don't have current loading issues and voltage transfer issues, it is best to have a low impedance source to a very high impedance input.
Anything else is tone control to an extent and that is why interconnects make a bigger difference on some systems then others.