Lighted batchi path at various tempos
I was curious how the shape of my batchi path changes as I play faster. Here are a few images showing the difference between 30bpm, 60bpm, and 120bpm.
The first image is my right hand playing at 30bpm. The faint blue lines next to my head are the path of the batchi tip as I strike toward the drum. The batchi rebounds off the drum and is then reset into alignment with the arm at the beginning of the pull-up. This reset causes the “kink”, a short, horizontal path of the batchi tip before it raises up for the next strike. By 60bpm (the second image), the arm is moving quickly enough that the bounce of the batchi is smoothly incorporated into the pull-up.
As the tempo increases, the height and width of the loops decreases. More specifically, the exaggerated path of the pull-up nears the path of the strike. (And when playing shime-daiko at even faster speeds, the pull-up path and the strike path are essentially the same.) Note that in all three images the arc just before striking the drum is essentially the same. Interesting!