Why just divided in 2 and recorded below center?

I am using a cassette recorder that copies to a mini SD card. This is what it looks like on Audacity. Sounds o.k. but why is it just 2 colors and below the zero?
audacity 2 color below line.jpg

That’s likely a hardware error called DC Offset.

Audio is always supposed to average out to zero (middle) no matter how loud or what the sound is.

Screen Shot 2019-06-22 at 13.25.56.png
Yours doesn’t. If you absolutely have to use this tape player and interface, you can force it to work with a couple of tools.

Drag-select and cut off the tall blue sections at the beginning and end.

Screen Shot 2019-06-22 at 13.35.18.png
Select everything remaining by clicking just right of the UP arrow to the left of the track.

Effect > Normalize > [X] Remove DC (and don’t select anything else) > OK.

You will have to do that to each tape or capture unless you repair the player or get a new one.

The blue colors in the wave are wrong or confused because sound doesn’t normally do what yours does.