It's impossible to know if it is system impedance or something else that leads to a larger perceptible difference on the Chord vs. the Chromecast.

Ostensibly, the Chromecast may be able to tolerate a wider cable impedance range without degradation. Therefore, both cables sound more similar than different. The Chord may be a tighter range and therefore the cables sound more different than similar.

Hence why a cable sounds like gold on one system and kaka on another.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated