Hi Ethan

> I have been trying to make the sound of a bouncing glass marble or
> steel ball bearing. I can't seem to to get it just right. Does
> anybody have an example patch for creating this sound

I am not sure what you mean exactly: The "falling" of a marble, which is
a row of sounds, which happen faster and faster, or the "rolling" of the
marble.

The "falling" is not easy, but doable. The best should be a single shot
sequence, where the CV of the sequence controls the speed of the
sequencer. The "klick" sound of the marble shouldn't be too difficult.
The fixed filter bank will be a nice tool for it.



The "rolling" is much more complicated:


I love sounds like these and thought a lot about them, but not very
successful (as the success of thinking is most times a matter of luck ;-) ).

The first idea is, that a marble or ball is a continous exciter, which
causes sounds in/with any kind of resonator. The resonator may be a
table plate, or the housing of the bearing or (as the nicest sound) a
glas bowl.

The fact that the exciter is a ball, causes several specialities:
1.) The excitation happens continuosly on the resonator.
This means, that each part of the caused sound can be heard at every
time (comparable to an shepard generator). Example: A knock of the table
causes a short püercussive sound. If I knock on the table two times
within a very short time, the attack of the second knock will sound
while the decay of the first knock. Now the marble "knocks" nearly
continously on the table, so each phase of the "knock"-sound sounds can
be heard at the same time.

2.) The excitation happens continuosly on another part of the resonator.
The sound will change continuosly, because the ball rolls over the
resonator, so that spot on the resonator of excitation changes
contiunously. As example: continue knocking with your finger on the
table plate and move your hand over the table - you will find that the
sound is changing with every knocking. So this may be quite simple with
a simple resonator as a table plate, but it will be become VERY
difficult with a irregular bowl as resonator....

3.) This description of the sound a marble as a continous row of single
sounds requires that we know how the "single sound" would sound like,
but we only can presume it. It may be quite dark (means lowpass filtered
;) ) a bit damped like short sounds.

If this is the case then I have to come to the conclusion that the basic
sound (topic #3) is very simple, but the influences of the continous
excitation (topic #1) and the continous change of the sound (topic #2)
make it nearly impossible, to create those sounds with the help of an
analog modular system.

I think, that some kind of physical modeling or granular syntesis will
be the better help. For simple copy, sampling with a good loop might be
satisfying enough.

It may also prove that my thought went completely to the wrong
direction. ;-)



Florian