Hey Albalex and others,
Just a general comment that could be helpful as people try various playing techniques and listen for the subtle differences: A couple of decades ago, I attended a two-day seminar with Jamey Aebersold, a saxophonist and music educator. (He sells jazz and blues play-along recordings by the way.) One of his tips to those who play a horn or other such acoustic instrument was to practice about two feet away from a wall, facing the wall. This way, the sound bounces off the wall and back towards you. You can hear your sound a lot better this way. I find it works well with melodica.