Well, here's my experience. First (and let's postulate that you have a good flute to begin with), right breathing and right embouchure are inseparable. We may think to analyze them separately, but where the rubber hits the road, it's all one thing, two sides of a coin. That said, there is a type of embouchure that concentrates and focuses the air stream in such a way that little effort is required even to play loudly. But you can't know that firsthand without agency of the breath, much less accomplish it - they're inseparable, remember? - so let's look at that. What I found - and this is simply a confirmation by discovery of what I've always heard from my betters - is that the thing is not to blow effortfully as if everything starts from from the mouth, but to simply breathe out, freely and unrestrictedly, from deep down where the breath originates naturally, the sensation of outbreath being firmly rooted only in the trunk and lungs, not in the throat or mouth. In fluteplaying, how much you breathe in is actually not as important as how you breathe out, and we'll get to that in a bit. There are two outputs, if you will: the diaphragm, which is the supply output, and the embouchure, which is the finer-tuned distribution output further down the line. The embouchure functions much like a transistor. It's like putting your thumb over the end of a hose: thumb and end are the embouchure, and the water flow behind them is the breath. The air jet that hits the flute's embouchure cut would be comparable to the water jet that emerges from where the thumb is; it's not that the water supply increases or decreases when you need more or less jet. That's the embouchure's job. It's been said, and I can confirm this, that when your embouchure is at an optimum, even playing loudly takes hardly more breath than it takes to speak. If you can do this, you're doing something right. Even though it controls the jet, the embouchure is actually relaxed, flexible, and finely operative. There's not so much tension, as there is just enough muscle tone to shape the mouth freely, not really so different than the muscle tone it takes to easily hold a pen lengthwise between the lips, just enough not to lose basic control of it. And that doesn't take much. Effort is minimal at best. Consequently, since there's no need for effort, breathing can be natural and unforced, because the supply it gives is sufficient for the purpose. Controlling the air jet's velocity and distribution against the cut is a function of the embouchure shape as it vents the steady pressure supply behind it, not in blowing harder. In this way the two work together, effortlessly. The intensity of the water jet from the hose is due solely to the thumb's positioning, neither pressing down any more than it takes to simply keep the thumb in place, nor in turning the faucet to adjust supply. Just as with the water behind the thumb, the air supply (or rather its fundamental rate of pressure, actually) should be a constant against which the embouchure operates in meting out an adjustable air jet. Obviously, then, the goal is to do more with less.sjpete wrote:Without some stamina, isn't it hard to get the breathing right?
My guess would be that the more breaths one needs to take, the less developed the embouchure is. I'd lay money on it. The grievous error is in thinking that development means more effort. Rather, development means finding the way to non-effort.
During long periods of playing, my hands wear out sooner than my breath, which is to say not at all. Nor do the lips get tired. That's how it should be. But it's hard to describe exactly how one should do this, because each mouth, lung condition, and flute is different. All you can do is gauge how effortful your playing is. If it's effortful, try this. If it's still effortful, try that. If it's less effortful, you might be onto something. Pursue it and see. Making your mouth hard as if you're lifting heavy weights, though, is not the way. The irony is that we usually have to go through this process anyway until we find that effortless place where both embouchure and breath operate freely, without striving.
The less effort, the freer you are to pick and choose where, when, and how you take your breaths. If you have reasonably functional lungs, no greater stamina should be needed than you already have naturally. Good embouchure moves powerful playing away from being an aerobic, athletic event, and toward being one of surprising ease. This is a matter of fine technique, free of brute force.