What interests me when issues such as this come up, is that I have serviced a wide range of models of sax. I play test them when I have finished the work. On sax I am self taught, and have significant playing and pit performance experience, but not a particularly accomplished player.
Yet I have never encountered such problems as the one described.
So I am inclined to believe that the problem is either due to a leak, perhaps as suggested above, or the player (embouchure, mouth cavity, &/or breath pressure), rather than the placement of an octave vent.
Yet I have never encountered such problems as the one described.
So I am inclined to believe that the problem is either due to a leak, perhaps as suggested above, or the player (embouchure, mouth cavity, &/or breath pressure), rather than the placement of an octave vent.