commas

All three work fine.

#2 and #3 are more common.

When I hear noise I think loud, I would prefer to say the audience was loud and appeared angry. But that is just my preference, not meant to be the final word.

Is this sentence correct? I am unsure if it should be 2 sentences:
Yes: I didn't want to walk in because the noise was too loud and the audience looked angry

All three suggestions are fine. Here is a fourth:

I didn't want to walk in: the noise was too loud, and the audience looked angry.

Isn't anyone worried about comma splices?

No.

JTT this was the only one I could find; that is, if you and I understand the same thing by "comma splice": "I didn't want to walk in, the noise was too loud, and the audience looked angry". But you might be onto something as there's something awkward about using the comma in place of "because"; it instead implies a sort of logical equivalence between the phrases, as if the noise and anger weren't the reason he didn't want to enter