Hi again Francis, you just fell into a trap… you were concerned about the sound…
If you try to control the sound, you are not focusing on pure process. This is using a different part of the brain and there is an element of expectation.
Whilst there is merit in focusing on a beautiful sound of course, that will be done in other exercises.
The Singing C Series is ALL ABOUT CORRECT PROCESS and disengaging the body below the neck when changing pitch; it is a more of a psychological development exercise.
Sticking with the process and sounding bad is the way to develop an efficient approach. We then work on tone purity without compromising the sensation of freedom that we developed when it sounded “bad”.
Let go of any preconceived ideas, explore the new sensations and merely observe whatever sound comes out as a result.
I know this goes against the grain of regular teaching however there are far too many players who sound great but are killing themselves; this will fix that.