Guest IBO,
I can see why people have trouble with harmonies. It took me a long time to be able to hear harmonies, but when it came it was a quantum leap. One day I couldn't do it and then I could. I still have trouble hearing what bluegrass singers call "baritone", the fifth interval. The "tenor" or third is what comes to me. I have to memorize the baritone if I want to sing it.