I can confirm through my faith.
an example is once I was walking down an upper path at the beach, a pinecone fell in front of me glowing brilliantly like the sun.
the feeling I got from witnessing this was unearthly. I know 100% it was a vision from The Holy Spirit.
I've had other visions, some would think hallucinations. for example, everything turning black and white, and a modern car turning into a model T right before my eyes.
as far as the audio, when listening to people speak, certain words or phrases "zap" me into a religious state of mind instantly.
as if a third party jumped into the conversation. without faith, I would think I needed my head checked.