What figure of speech is used in “...the microphone dropped on the floor, sending a vexatious clatter out of the twin sound boxes”?

Onomatopoeia is a figure of speech in which a word phonetically imitates or resembles the sound it describes. In the expression "the microphone dropped on the floor, sending a vexatious clatter out of the twin sound boxes," the word clatter is onomatopoeia. It imitates the sharp, rattling, crashing sound that a microphone produces when it strikes a hard surface and the impact reverberates through the speakers.

The effect of onomatopoeia is to make the scene more vivid and immediate for the reader. Instead of merely stating that the microphone made a loud noise, the word "clatter" lets the reader almost hear the sound, bringing the moment to life.

This is not a simile because no comparison is made using "like" or "as." It is not irony because there is no contradiction between what is stated and what is meant. While the adjective "vexatious" adds emotional colour to the description, the primary and most identifiable literary device in this expression is the sound-word "clatter," which is a classic example of onomatopoeia.