Learn Italian: Lo senti bene, l'audio? - Do you hear it well, the audio?

This is a perfect example of "Right Dislocation," which is extremely common in spoken Italian. You state the core action with a pronoun first (Lo senti bene - "Do you hear it well"), and then add the actual noun at the end (l'audio) to clarify exactly what "it" is. While it sounds repetitive in English, it is completely natural in Italian.

How do I know which pronoun to use at the beginning of the sentence?

The anticipating pronoun must always match the gender and number of the noun you've pushed to the end of the sentence. Since audio is a masculine singular noun, you must use the masculine singular direct object pronoun lo. If you were asking about a song (la canzone), you would change it to match: La senti bene, la canzone?

Why is there a comma before l'audio?

In written Italian, the comma is required for right dislocation to show that l'audio is a clarification attached to an otherwise grammatically complete clause (Lo senti bene). When speaking, this comma represents a slight pause and a drop in your voice's pitch right before you say the dislocated noun.

Why use senti here instead of ascolti?