Could somebody tell me how to improve the top 2 notes (C#, B) in the second octave in terms of flute design/making? At the moment, it is hard to make a good sound out of them while the bottom notes in the first octave can be played with ease. Has this something to do with the embouchure shape, size and the undercut, for example? Thanks.
It shouldn’t be very hard to make the notes sound well if you are using a bore-size that is reasonably compatible. Making the upper second octave notes play in tune is the problem on cylindrical bore flutes. Undercutting the finger holes on the embouchure side of the hole will help. However, to get the notes up to pitch, you will need to use a wedge in the headjoint or have a taper in the headjoint. Please see the page “Tipple-Fajardo Wedge” at my website.
There are a couple things that could be affecting it. One could be just the overall cut of the sound hole (jagged, rough, etc), but if you have a good wedge, a reasonably good sound hole, and you’re pipe isn’t majorly bowed, it’s probably just your way of blowing. I would try lots of different ways of blowing it, and see if you ever get to a spot where the upper and lower notes are strong. If that’s not it, your wedge may have too steep of an angle or something like that. Another variable could also be your cork placement. I would have someone else try your flute, and see if they get a good upper range.