The k in kde sounds like b and I hear 'bde jsem'. Is that how Kde is pronounced?
Certainly not. It's pronounced /gde sem/.
"k" becomes /g/ due to voice assimilation (the following /d/ is voiced), and "jsem" is normally pronounced /sem/.
Thank you, that helps me a lot.
So, it sounds to me that you are saying the Duo pronunciation of "kde" is not correct. Is that what you are saying?
It's pronounced /gde sem/, Duo pronounces it /gde sem/ (at least the female voice does), so it is correct.