In this example, what is meant is conveyed through a misapplication of one part of the body to another.
As one said that disliked a picture with a crooked nose, "The elbow of his nose is disproportionable" —J. Smith

The word "parricide" literally means a killer of one's father, but for lack of proper terms, is also used to refer to killing one's mother or brother:
In his rage at Gertrude, Hamlet nearly became a parricide like his uncle.

In this example, no parallel idiom to "sight unseen" exists for things auditory, so the idiom is wrenched from its proper context to this unusual one.
He was foolish enough to order the new music CD sight unseen.

Similarly, there is no word comparable to "sightseeing" for a similar sort of tour done with sound, and so a familiar (if technically inappropriate) use of "seeing" is used:
The podcast included a soundseeing tour of London's theatre district.

• metaphor
• acyron
• metalepsis

• Comparison

• Figures of Speech: Vices