I have seen this concept several times in the Forum and I confess I do not know what it exactly means. There seems to be "blow hole undercutting" but also "tone holes undercutting".

I would like to learn about this subject and have an idea why this make a difference in the sound produced by the flute and the difficulties in their manufacturing.

Thanks!

This may be a good starting point.

http://www.yamaha.co.jp/edu/english/factory/fl/fl_002.html

Thanks. I enjoyed doing the factory visit tour.

There is a simple but interesting explanation about the meaning of the different "cuts" in Yamaha flutes. I had not seen those explanations before.

Now, there seems to be also a kind of tone hole undercutting. I suppose it cannot be done with drawn tone holes (this would weaken the hole tube base too much).

So, for tone hole undercutting, what is the advantage and how are they made?

Does tone hole undercutting affect the tone or quality of the sound? If so, how come?

I think that the drawn and/or undercut tone holes are considered more efficient and may aid a bit in projection but aren't all that important.
On the soldered tone holes (especially older instruments) the silder seal must be good or the flute will play weak.
Another point about drawn holes is that generally the tone hole edge may be rolled and the width of that edge may be three times thicker than on soldered ones. This makes the necessity for a level tone hole all the more important.

I suppose that drawn tone holes should have a "not so sharp" (word?) bend at the joint of the hole wall with the body tube. Because of the drawing process, the joint should tend to be round and not sharp.
In any case those holes would be difficult to undercut (if at all possible), but could be re-formed by stamping or a similar mechanical process. Is it so?

I would say so. (Not in that end of the business) but the thing is that the drawn ones can be formed to do a similar thing.

I remember a discussion with Galway and Johan Brögger about his design ideas and he was advocationg a certain shape to the hole which produced a venturi (sort of) effect. I think that he was writing/speaking about his double conical tone holes shape. This concept may improve the efficiency of the tone. See the Brögger interviews at the bottom right of the page:
http://www.thegalwaynetwork.com/interviews/intervue2.htm
These interviews are very educational, lengthy and difficult to understand but in the second interview beginning at about 19:20, he discusses in depth these tone holes and the diameters.

My point is that there is a certain school of players that are more into the traditional older French flute model. This would be the soldered ones with little or no undercutting. They can project a fine tone without all of the modern additions that change to tone from the older sound to a more bright & edgy one.

Thank you. It's amazing all the things you know...

What about the things that you don't know that you don't know about? (:-)

Joe B

To know that one does not know so many things is a sign of wisdom; to ignore that one ignores so many things is a sign of ignorance...

I know the things I think I dont know are the the things I really know I dont know