Doepfer

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