Question

Knocking softens,fades is what figure of speech

Answer 1

hyperbole is figure of speech

Answer 2

The figure of speech used here is the Metaphor.  

Explanation  

The Metaphor is a figure of speech used in poems to make a comparison between two things directly in the absence of words such as 'like' and 'similar'.  

In the sentence, " the knocking fades..", the knocking refers to the carving of a statue.  

The poet has compared the carving sound, which is the sound made by the chisel on the statue to the sound of the knock usually made on the door.

So it is a metaphor.

Hope this helps.