Hi all trumpeters,
I think that obviously it is not more air but more pressure that permits to play higher.
But how do you make higher pressure? The response is that you have to change shape and tension of the lips (higher resistance) and to compress more or less the air by the expiratory muscles (the sound volume).
But for me it is by thinking to compress the air that determines by reflex the right shape of the embouchure and not the opposite!