Sound waves. What are the differences between these 2?

Question

Audio

I encountered a sound wave that is unlike any I have seen before. I tried to find it on the Internet, but whatever I put in the search, everything is not right. The 1st picture shows a wave familiar to me, and the 2nd one deviates downward on its axis. Can you throw off articles or textbooks where it is described, what it is and how to understand it? Thank you)

Answer 1

https://www.google.com/search?q=DC+offset