Last year I taught a Survey of World Music class and subsequently discovered and fell in love with Hungarian folk music through artists such as Márta Sebestyén and Muzsikás. I have played Irish traditional music and other aerophones for years and was very glad to find a selection of instruments from hungarianfolkmusic.com.
I purchased a 6-hole C furulya, a D tilinkó (overtone flute), a 6-hole F double furulya, and a D 5-hole Moldovan/Romanian kaval. (Like I said, I was inspired.) An interesting feature of these instruments is that the fipple is constructed on the bottom of the flute body rather than the top, which can make it tricky to hold in certain positions, but allows for a very interesting technique. Here's an example of someone actually doing it: https://www.youtube.com/watch?v=DJoJB_1mQNM And here a description from the above site:
I also just found that Winne Clement demonstrates it in some of his kaval videos: https://www.youtube.com/watch?v=LPMedmlbNb8If you cover the top of the window with your jib / lower lip, you will hear the octave of the current note. It is enough to cover the upper ~2 mm. After that you should do "growling" sound with your throat and you will hear a very loud, overtone-rich sound.
Essentially you partially cover the fipple opening with your lower lip and also activate your glottis and "growl", either a drone note, the melody, or a countermelody.
MY QUESTION IS: how does this technique work when you overblow? Specifically in my kaval, I am having issues moving through the different "octaves". It's as long as a Low-D whistle, but you never play the fundamental in its original octave. You overblow to the second (D), third (A), and fourth overtone (D). I'm fine doing this embouchure technique in the second octave, but can't get it to work with the third or fourth.
Anyone who has any experience with this, I'd be appreciative of any help!
Best,
Matthew