I've had a similar experience with rounded rectangle embouchures Terry. If you can play an elliptical or round embouchure, then you'll generally have no problem getting a strong tone from a rectangular embouchure. The opposite does not seem to be the case though.
Also, those rectangular embouchures do seem to give access to very loud playing quite easily, whereas the smaller more rounded embouchures make it much more challenging. I think the area calculations give a clue to why that
is the case. For a given set of long and short embouchure dimensions, the rectangular embouchure will have a much larger area than the round or elliptical one. I suspect we can agree that the following general principle holds: the larger the embouchure hole, the louder the flute. This principle seems to extend more broadly to tone holes too.
But louder flutes are not necessarily easier to play. So I think there
is a second principle lurking in there somewhere which has to do with the radius of curvature of the splitting edge. As the radius of curvature of the splitting edge gets longer, it becomes easier to find the sweet spot for generating a robust tone, and the embouchure
is more forgiving. A longer radius of curvature can be obtained either by elongating the long dimension of an elliptical embouchure, or by changing the shape to a rectangular form, or by taking a round embouchure and pushing the sides further apart, essentially inserting a rectangular section between the two sides of the circle. You can see examples of all of these shapes in antique and modern flutes, and I view them as attempts to make an embouchure that
is louder and more forgiving.
But what I'm really interested in
is what we sacrifice by doing this. One way of looking at the large, round, embouchures of the early-mid 1800s London flutes
is that they are simply a louder version of the small, round, baroque embouchure (same shape, just bigger). You can see a similar trend in German and Austrian flutes, where the early rectangular embouchures of flutes by Koch were copied and gradually enlarged over the years. And you can even see this trend in the elliptical embouchures, where a late baroque flute such as a Palanca, already has an elliptical embouchure, but only sized 10.3 x 8.4. Over the years the same shape was used on many later flutes, but the size grew dramatically. I have a Palanca (copy, not original), and while its embouchure
is more forgiving than the even smaller, round, baroque embouchures, it
is nothing like playing our modern elliptical embouchures. In fact, its radius of curvature along its long edge
is tighter than that of all the larger round embouchures I listed in the first post, and it takes a much more focused embouchure to play it.
Michael Lynn has published a nice data set and discussion on embouchure sizes and shapes here, with plenty of examples from earlier flutes:
https://www.originalflutes.com/links/em ... sions.html
It seems clear to me why there has been a
search for both louder and more forgiving embouchures. But I am curious about the idea of a round embouchure that
is both loud enough, and forgiving enough, but which affords some desirable properties in terms of tone or expressiveness that are lost when we relax the radius of curvature too much. My interest in this
is driven, in part, by observations of my own playing preferences. I've generally enjoyed larger embouchures, but I've noticed that nowadays my preferences seem to be trending more and more towards those with a tighter radius of curvature. It has made me wonder whether this
is a symptom of a steady improvement in my own embouchure, combined with a quest for a particular tone that exists in my minds ear and which perhaps got there by listening to past players who used rounder embouchures.