Hi Cristian
Purely by listening to the sound examples my guess is that the control doesn't need to be at sample rate. There is nothing in there that constitutes changes greater than 1 khz. But what I also noted is the cleanness (non aliasing) of the tones, so I'm guessing this is down to the algorithmically generate signals which would be at sample rate. The paper does have a lot of big words that I don't understand and it doesn't really tie down exactly what is happening inside the sound generator. So by using my ears I'm going to make a big guess.
Lets forget for one moment the brake points and look at the second order system. lets start by generating a sine wave and cos wave in algorithmic form at sample rate. This is calculating on the fly with no lookup table.
Look at this simple formula written in basic.
10 X=100 : Y=0: Freq = 0.05
20 X=X-(Y*Freq)
30 Y=Y+(X*Freq)
40 do something with X and Y like plot it on a graph or feed speakers
50 GOTO 20
Believe it or not this simple program will make X produce a sine wave and Y produce a cos wave. Varying Freq will change the frequency but this must be less than 1.
I've implemented this in Kyma in "sine wave formula" attached. The freq is controlled by a constant but that can be replaced with a sample rate signal.
I don't know the details of their algorythm but also included in the attached is "Petes
AlgaTone?". It is something I've been thinking about for a while. It algorythmicaly generates sound at sample rate.
It uses the input output charictaristic modules to deform the liniarity and although the controls are at capy rate the interpolation is all done at sample rate. See the X and Y nodes
Noise has been added and there are a few additional modules added to maintain stability. I don't know if this is anyting like what they were doing but it does give a large variety of sounds even without any control cirtutry added.
If you want to make sure that it doesn't resolve to silents you must keep energy at 1 or greater and "UnStable" should be kept at close to zero for lower pitch and complex sounds.
By seeing what I've done you may be able to adjust it into their formulars and you could do the control stuff in normal capy talk. I didn't use the feedback modules but if you are on a paca you could replace the memory writers and sample players with them.
I hope this makes sense and I hope you enjoy "Petes
AlgaTone?".
Pete
BTW if any one wants to transfer "Petes
AlgaTone?" to the tweaky be my guessed.
