Update: I've been playing the Yamaha exclusively for the past three days, and things are sounding better. I know this sounds odd considering the larger bore the Yamaha has over the Conn, but Conn actually blows more freely for me. If I were to guess at the reason for my problem I would guess with some certainty that I was over blowing the Yamaha, IE increased feeling of back pressure means must blow harder. I honestly must say that I've not consciously changed anything but that things seem to be working themselves out by focusing on my routine. Thank you all for your great comments, and yes. I do strongly recommend everyone play an instrument before purchasing it, even if you are familiar with that instrument.