Ridge radio/speakers

[T-Rod]

I bought a ridge ranch that had the head unit installed by previous owner. He worked at the dealership from which he bought it. I didn’t find out until later that the speakers didn’t work correctly. They are extremely quiet. I was looking at the way they were wire and I believe they are incorrect. It looks like there was a black and white wire together for one speaker and another black and white wire for another speaker. But it looks to me that when he pulled each pair apart to connect them to the speaker wires, that he then put one speaker on the white wires and one speaker to the black wires. Does anyone know which is correct. I do not have any paperwork on the head unit itself.