Whistling for me is an effortless activity and I don’t need to think about what’s going on in my oral cavity nor lips in order to change pitch.
Nevertheless I have decided to spend some time analysing what’s happening as I change pitch when I whistle. I have realised that actually very little change is happening to the size of my lip aperture. In fact I only need to open it a bit to produce the lowest notes I possibly can. What is really driving the change in pitch is what is happening inside my oral cavity. I have noticed my tongue is always arched, no matter the pitch. However the tip of my tongue is in constant motion. For low notes the tip is well bellow my lower teeth, and as I ascend it moves up. On the highest note I am able to produce the tip is in-between my teeth touching the lower lip. Also, the movement of the tip of the tongue is in tandem with the jaw which moves forward for higher notes and backward for lower notes. Interesting is also the fact there is always in a U shape in the tongue, where the curve is very tight on high pitches and very large on low pitches.
Regarding the aperture corners I am still confused.. Should I use the tension in the corners to bring the lips forward as in a kiss filling the mouthpiece with more meat as I ascend? I am actually trying not to think about any of these things while I practice right now with the lead pipe. Trying to do as I whistle, effortless and no thinking.
The reason why I posted the challenging question is, I thought that lip clamping is a synonym of very tight lips. And for very tight lips to vibrate we need to Overblow. So my thinking was that if we don’t Overblow and just release the air, if there is sound, then it must mean the lips are are freely oscillating.