I think some have interpreted that it’s important to form a certain pucker/forward shape with the lips in order to get results / follow what Greg is instructing, etc.
I don’t believe that is the case at all, I believe the point of the AahhhOoohhh is really more of a mental thing and more about changing pitch, not about getting the initial vibration.
I would presume that most people’s problem is not about how they put the mouthpiece on their lips, what position, etc. Not to minimize that aspect–I do think the visualizer and considering where the air is going is useful/important.
However, I believe the most important factor, the one which most of us fail on, is tightening the lips/clamping down and overblowing.
I think most people could probably place the MP on their lips as they’ve always done and focus from there on ensuring they’re getting a sympathetic vibration, that they’re changing pitch by engaging the aperture corners inward horizontally from the sides, rather than pinching top-to-bottom like a clam. And paying attention to how being relaxed feels and sounds better, more resonant, etc.
I think some of us, myself included, didn’t realize that we could change pitch by moving the lips inward/forward (ooohhh) towards the center of the MP / air column. I think I felt that wasn’t natural, would result in an extreme pucker, airy sound, etc.
To be honest, I dont think it probably ever occurred to me and despite the fact that I took a lot of lessons and had various band directors, no one ever suggested it.
I think part of it was the teeth–I was cautious about pressure and felt like I should keep my lips out of the way of my front / eye teeth, so i used more of a flattened out / smile embouchure. As I ascended, I would roll under my bottom lip and thin out my lips and add pressure–which worked to a point.
Now I think of it more as I need my lips engaged (aahhh ooohhhh) and ready to tighten inward (oooohhh) from the sides horizontally inward as I ascend. I think of getting my top lip in front of my front/eye teeth–I think that’s mentioned in the Maggio book as well.
It’s more mental though, I place the MP on my lips in what I think is the simplest, most natural position possible.
I beleive actually that the method Greg is describing is actual the most natural, efficient way to make sound on the trumpet. In fact, that’s the whole point and key to developing efficiency and effectiveness on the instrument–the easier we get to High C, the easier it will be to get higher, etc.