So Michi, if you've figured this out, any tips? Anyone else?
I can't wait 9 years!
One of the many things the djembe taught me: patience
Here is a sound clip of my third slap:
This is nowhere near as clear as I would like it. Especially when playing a pattern such as passport, I'd like to be able to work out the tonepalo hits much more clearly. It'll take me several months (years?) to perfect the technique, but at least it's a start.
Here is an image where I indicated the approximate impact areas for normal tone (yellow), normal slap (pink), and third slap (green).
The spot for the third slap on the drums I tried (three different ones) is quite small, and even moving the impact point by very little (say, more than 2mm) can make the sound degenerate into a normal tone or slap. The spot is sensitive mainly to movement in or out: too far in or out, and the sound disappears. In the sideways direction, there seems to be more leeway: I get the sound anywhere within about 10cm from the spine. I can also play it at the point 90° to the spine, but it is much less pronounced there. Proximity to the spine seems to help.
Also, the spot isn't the same for each drum. It's at a slightly different distance from the rim for each of the drums. Tighter drums seem to make it easier to get the sound: I tried with a fairly low-tuned djembe, and couldn't get anything whatsoever.
I strike with only two fingers, near the finger tips, but not
with the finger tips as I would for a slap. You can see the approximate contact patch in this image:
When you try to find the resonance point, don't strike too hard. It seems easier to hear the overtones when you play quietly. Also, try and keep the contact patch small. Move around near the rim and tap lightly. Somewhere around there, you should find a spot where the pitch changes ever so subtly. Work that spot, and you should get there…
Oh yes, take all of this with a grain of salt, too. This is only how I do it, and other people may find the same or a different resonance by striking differently. But I do believe I'm on the right track. I demoed this to Bangouraké at Bundagen and he smiled and nodded. He also made a correction to my hand position that made it a little easier to transition between normal tones and slaps and the third slap: to strike a third slap, I have to turn my wrists in to get my fingers onto that resonance spot. Mohamed suggested to play the normal tones and slaps that surround the third slaps with the same turned-in wrists, so there is less overall movement. He's right: things are a little easier that way because there are no frantic hand movements.