I did hear something similar to the Sierra Sounds when I lived in Wisconsin. It was a strange nighttime experience, things happened and after that I would not go out during the nighttime hours. There is a certain part of the Sierra Sounds with high pitched almost dog-like sounds, so similar to what I heard in WI that I almost cried. It really unsettled me and took a few weeks for my brain to process. I can also say that in addition to hearing breathing made with astoundingly large lungs that the breathing sounded wet, slightly congested in a weird way.