Learn Polish: Ten wokal jest cichy, dlatego musimy go przerobić. - This vocal is quiet, that's why we have to rework it.

The base verb robić means "to do" or "to make." The prefix prze- often adds the sense of doing something again, differently, or thoroughly. Here, it turns "to make" into przerobić, meaning to "rework," "remake," or "alter" the vocal track to fix its volume.

Why do we use go instead of jego for "it"?

We use go because it is the short, unstressed form of the pronoun on in the accusative case (used for direct objects). Because wokal is a masculine noun, we use a masculine pronoun to say "it". You only use the longer form jego for emphasis, after a preposition, or at the very beginning of a sentence.

Could I use dlatego że instead of just dlatego here?

Not without flipping the sentence! The word dlatego means "therefore" or "that's why," introducing the result of a situation. The phrase dlatego że means "because" and introduces the cause. To use it, you would have to say: Musimy go przerobić, dlatego że ten wokal jest cichy. (We have to rework it because this vocal is quiet).

Does wokal just mean a musical vocal track, or can it mean a vowel?