(0,1), (0,2) and (0,3) modes of vibration for a timpani

Question

For a timpani, when hitting it in the center, how do you produce these three modes of vibration? Second mode has a higher frequency than the first, does that imply do you hit the timpani harder?

Thank you!

Answer 1

Some information for this answer taken from The Well Tempered Timpani.

Since a real world timpani is not perfectly shaped and can never be perfectly struck in the center, any time you strike a timpani, you will always activate multiple vibration modes.

Also, timpani membranes are two dimensional, so the numbering of the modes is more complicated. I'm going to assume the modes you are talking about are the (0,1) mode ("first"), the (1,1) mode ("second"), and the (2,1) mode ("third"). When a timpani is actually played, the preferred modes that are emphasized are actually (1,1), (2,1), (3,1), (4,1), and (5,1), and sometimes (6,1). The (0,1) mode is inharmonic with the other modes, so it is generally avoided to make sure the timpani is playing a note.

By striking a timpani as close as possible to the exact center, you will activate many vibration modes, but the "first" mode, (0,1) will be the loudest. So striking firmly in the exact center is how to hear the first mode. This might not sound like normal timpani playing, since normally they are played closer to the edge, and should come across a bit boomy. More like a bass drum.

To hear the "second" mode, (1,1) best, you have to both strike the timpani in a way to make the second mode louder and also damp the timpani to make the first mode more quiet. To emphasize the second mode, strike the timpani about 1/3 of the way along a diameter of the timpani. Another way to say that is to strike it about 2/3 of the way from the edge to the exact center. Also while you are striking the timpani, gently place at least one finger in the exact center of the timpani. You may get better results by trying to make a line with your fingers that goes through the middle of the timpani and make sure the line is perpendicular to the line from the edge to the center that you are striking along. You might have to adjust the strike point slightly somewhere between 1/2 to 2/3 the distance from the edge to the center (closer to the center). I may edit in a picture or diagram later if I can, since that would be clearer.

If you succeed in activating the second mode, it should sound like it's an octave higher than the first mode. Resist the temptation to strike a lot harder, a firm strike is what you want. It's the position and damping that controls the vibration, not the hardness of the strike (too soft or too hard will change the vibration modes, but in a more uncontrolled way).

Each higher mode is harder to isolate, so the "third", (2,1) might require a lot more practice. I'm actually not sure how to activate the third, but I have an educated guess. Again you want to place your finger in the center of the timpani, and ideally you would damp in two perpendicular lines going through the center of the head. Then you would hit inside one of the four quarters of the head created by the two lines, close to the middle of the quarter, and slightly towards the overall center of the head.

Answer 2

Without being a timpanist, I will hazard a guess.

First, you will know when you have hit the higher modes because the tone changes as you would expect.

I suggest gently touching the surface of the timpani with one finger as you play it. The exact location where you touch it will determine whether your finger simply dampens the sound or dampens only some modes of vibration.

The round surface is symmetric in rotation (even if the modes of vibration aren't), so you can find out where to touch the surface just by testing from the outer rim to the center (like a needle following the groove on a record) and by testing sets of points ( for ( >0 , _ ) modes) that start at any arbitrary "cardinal direction" ...you don't need to explore the entire surface.