Devialet Expert isn't good in showing secondary harmonics?

[Jeffaz]

A brazilian audio forum person, who represents a well-known cable manufacturer, and himself an experienced audiophile, told me that Devialet Experts line aren't good enough in showing secondary harmonics.

This conversation took place when I was interested in buying speakers cables from him.

Have any of you of Devialet Chat ever heard about this "secondary harmonics" issue?

Jefferson