Would you agree that "immeasurably small" is the same as "not noticed at all"? Therefore something "very noticeable" ought to be measurable, correct? If so, please advise where in the literature of cables one can find a side-by-side comparison of phase shift or frequency response pitting one cable against another under identical conditions.
I would also contend there is no way a reasonably short cable (<4 feet) could possibly contain enough capacitance to affect the loading of the input, though there may be some poorly made beast out there that does. Shielding is a different issue, which can affect sound, particularly in low-current turntable connections. But added RFI is not the issue; sound quality is. I still don't know what independent variable can be assigned to a cable for this.