This page is more to make the sweet spot issue explicit then to make a rule of any kind.
The embouchure of a traverso can be played more or less covered. The embouchure can be played more or less turned in or out. The angle under which we blow with respect to the edge can also be different. So what is best is a logical question.
Many notes are played with a different use of the embouchure of course. Nevertheless there is a sort of reference position. This I would like to call the embouchure sweet spot.
Traverso embouchures differ quite a lot. It is immediately clear that they differ far more then the modern Boehm flute embouchure. The undercutting may be pointed into the bore or have downward wings.
So a first question is if there is one rule for all embouchures on coverage , turning in and angle.
Different professional players seem to have different opinions. I have heard the opinion that, yes cover all about one third form a top player.
I also know top players who think differently. Personally I think that they should be played quite differently.
The most important point I want to make is that by simply playing d2 while varying the way one plays a “personal” sweet spot can be found.
There are four main aspects that decide the embouchure sweet point.
These are:
-taste,
-size and form of the embouchure,
-lips,
-carrying of the tone.
Lets look at these aspects one by one.
Taste:
Some players like to play with the mouth hole turned in very much. I suppose that that is because they have a certain sound that way. The fact that it has a disadvantage with respect to the carrying of the sound to the public may not be so important for them. So taste clearly plays a role in the players choice of sweet spot for a certain flute. I personally, as the maker think that my flutes should be played with a certain choice for the sweet spot. This is my taste. I am not going to give hard and fast rules for the sweet spot aspect.. However, there is only one flute I make where it really is almost impossible to like it if you have a very different way of playing. That is the Wijne flute. I will come back to that after those four points.
Size and form of the embouchure:
The smaller the embouchure and the further the undercutting the less you should cover. Alas this is the only explicit “rule “ I can give and on top of that it is my opinion. The sometimes very different form of the undercutting no doubt also plays a role but you have to experiment.
Lips:
They are yours and therefor you should again experiment.
Carrying of the tone:
I have to sum up some things:
-the wood vibrations of a flute are hardly heard by the audience
-the audience hears sound from the holes
-the main source of sound for the audience is the mouth hole
-part of the embouchure sound goes into the flute and therefore contributes less to what the audience hears
-the sound that goes over the mouth hole is very important for what the audience hears (!).
Therefore the choice of sweet spot has a large influence on the way the audience hears the music!
The Wijne traverso has a tiny mouth hole. Amazingly it has quite a big traverso sound! So the idea that the size of the mouth hole is decisive for the sound volume is incorrect. However, if one covers the mouth hole for instance one third it is a very modest flute. The sweet spot should be chosen hardly or not covering the mouth hole depending on the lips.
Then it plays amazingly.
Possibly flutes with a very small mouth hole should be played more or less like this.
