I recently purchased a Parduba 7 mouthpiece. I have found 2 things that have really made an impact.One is that the lower and middle register is amazing. Two is that my high range disappeared. I could play an A over high C on my schilke 14A4 and now on the Parduba I can barely play a high C. The schilke mouthpiece has been bored out twice, and a clearly visable difference in bores is visible. Could it be that the Parduba is giving me trouble because I can't put enough air through? Or could it be because of the double cup?