Je suis tombé il y a quelques temps sur ce post de Cunka qui évoque une fonction cachée sur la série K, un générateur aléatoire de DSP
http://www.cunka.com/forum//index.php?topic=24.0
En gros, via une manip particulière détaillée dans le lien ci-dessus, on peut générer une fonction DSP qui sélectionne de façon aléatoire 3 fragments de DSP existants.
Je n'ai pas encore testé, apparament cette fonction produit souvent des résultats pas très exploitables mais on peut également rentrer soi-même les valeurs des bits utilisés pour la calculer et il y a quelques exemples de résultats intéressants qui sont fournis
Comme le lien n'a pas l'air de fonctionner correctement je fais un copier-coller du post en question mais il manque les copies d'écran.
Le sujet se trouve dans la section Class room du forum Mastering Vast sur cunka.com (il faut par contre être enregistré pour pouvoir y accéder)
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What is the "Random DSP Generator"?
A limitation of the K2000 series is that the DSP functions are fixed. While you can combine them in many ways, and control them, you are limited by a select amount of DSP’s for any given Algorithm.
To expand the possibilities of VAST, John Teele (former Chief Software Engineer at Kurzweil R&D) wrote the code, which became known as the Random DSP Generator.
Why isn't this documented?
The random DSP generator was an experiment which Kurzweil R&D were doing. The code is buried in the Kurzweil operating system, but is accessable to users. Because it is was an experiment, it is not recognized as one of the Kurzweils features, thus it is not documented.
How does it work?
In order to use the random DSP generator, one of the existing DSP functions has to be “overwritten” in order for it to work. The ALLPASS filter was chosen for this purpose, as a lot of VAST programming does not seem to use it. So any Algorithm that uses the ALLPASS filter will be able to use this technique.
It works by taking pieces of three existing DSP functions. The start of one, the middle of another, and the end of a third. This selection includes the double and triple sized DSP blocks.(Which are made up of special one sized blocks.) It then combines them and writes this new function over the ALLPASS filter.
Can you tell me more on the technicalities of it?
The key to the selection of the three pieces is done through the pseudo-random number generator. It remembers the initial value that was used as the input to the random DSP generator. That way, you can re-enter the value later to get the same DSP function back. You can also enter any starting value to enable you to experiment with it.
The numbers are really a random seed, a long (four byte) value that is plugged into a pseudo random number generator as a starting point.
seedval =(number1 << 24) | (number2 << 16) | (number3 << 8 ) | number4
The random generator is called three times.
rand1 = random(seedval)
seedval = rand1;
rand2 = random(seedval);
seedval = rand2;
rand3 = random(seedval);
seedval = rand3;
The three random values are used to select one of the three DSP functions.
E.g. Rand1 controls where the first section comes from.
How can I use it?
Its important that before you do anything that you SAVE everything in RAM.
For users who leave there machine on continuously and do not ever turn it off, its recommended that you do turn it off after you have finished experimenting with this feature. This will allow the K2 to return to its normal state.
Start by constructing a 1 LAYER PROGRAM using ALGORITHM 8.
On the GAIN page, set the “Adjust:” parameter to 0dB.
Assign the Mod Wheel (Mwheel) to "Src1".
Set the "Depth" to -96db.
On the ALLPASS page, set the “Coarse:” parameter to its minimum.
Assign the Data Slider (Data) to "Src1:".
Set the “Depth:” to its maximum value.
Set the Keymap to "163 Sine Wave." (K2000)
Now save the PROGRAM.
This is the “template” that you will use for the random DSP generator.
Now press the MASTER button.
Now press the UTIL button.
Press the blank soft button. Make sure the Modulation Wheel is all the way down and the DATA slider is in the middle position.
Now press the EFFECTS button.
Each time you press it, the Kurzweil generates random DSP functions instead of the normal Allpass filter. Most of these will be pretty unusable, but by pressing it enough times, you will find some that make sound, maybe even sound interesting. Of these the majority will be some type of LOUD distortion. By moving the data slider, you will hear the effect of varying the DSP's coefficient, sometimes interesting. By moving the mod wheel, you will hear the effect of lowering the gain before the DSP, often interesting on distortion types of DSPs.
When you find something you like:Press the QA button.
The Kurzweil will tell you a 4 digit number that you can write down, to get back to that DSP. After you write down the number, press OK. The Kurzweil will prompt you to enter a previously obtained number. You can either enter the four numbers or press OK twice to cancel. In summary, the QA button lets you either read the current randomly generated numbers or enter numbers that you want (or both).
Pressing the EFFECTS button randomly generates DSP instructions for the Allpass function, starting from the last numbers you entered, or from 0 after power up or a soft reset. You can start a session by entering previously obtained numbers, because otherwise you are likely to cover the same ground as you did previously.
Another idea is to start a session by entering 4 arbitrary numbers - that way each session searches a different space. Also try other keymaps, you can get good results with samples that have a lot of high frequency content.
One thing you will notice is that if you do this, any other programs which use the Allpass DSP will be completely screwed up until the numbers are set back to 0 (which happens each time you turn on the unit, so you can't permanently screw up those programs).
Here are two examples that make noise with the template program:
140-168-238-108 (hold chords and move slider)
126-173-28-236 (really distorted when more than one note played)
http://www.cunka.com/forum//index.php?topic=24.0
En gros, via une manip particulière détaillée dans le lien ci-dessus, on peut générer une fonction DSP qui sélectionne de façon aléatoire 3 fragments de DSP existants.
Je n'ai pas encore testé, apparament cette fonction produit souvent des résultats pas très exploitables mais on peut également rentrer soi-même les valeurs des bits utilisés pour la calculer et il y a quelques exemples de résultats intéressants qui sont fournis
Comme le lien n'a pas l'air de fonctionner correctement je fais un copier-coller du post en question mais il manque les copies d'écran.
Le sujet se trouve dans la section Class room du forum Mastering Vast sur cunka.com (il faut par contre être enregistré pour pouvoir y accéder)
---------------
What is the "Random DSP Generator"?
A limitation of the K2000 series is that the DSP functions are fixed. While you can combine them in many ways, and control them, you are limited by a select amount of DSP’s for any given Algorithm.
To expand the possibilities of VAST, John Teele (former Chief Software Engineer at Kurzweil R&D) wrote the code, which became known as the Random DSP Generator.
Why isn't this documented?
The random DSP generator was an experiment which Kurzweil R&D were doing. The code is buried in the Kurzweil operating system, but is accessable to users. Because it is was an experiment, it is not recognized as one of the Kurzweils features, thus it is not documented.
How does it work?
In order to use the random DSP generator, one of the existing DSP functions has to be “overwritten” in order for it to work. The ALLPASS filter was chosen for this purpose, as a lot of VAST programming does not seem to use it. So any Algorithm that uses the ALLPASS filter will be able to use this technique.
It works by taking pieces of three existing DSP functions. The start of one, the middle of another, and the end of a third. This selection includes the double and triple sized DSP blocks.(Which are made up of special one sized blocks.) It then combines them and writes this new function over the ALLPASS filter.
Can you tell me more on the technicalities of it?
The key to the selection of the three pieces is done through the pseudo-random number generator. It remembers the initial value that was used as the input to the random DSP generator. That way, you can re-enter the value later to get the same DSP function back. You can also enter any starting value to enable you to experiment with it.
The numbers are really a random seed, a long (four byte) value that is plugged into a pseudo random number generator as a starting point.
seedval =(number1 << 24) | (number2 << 16) | (number3 << 8 ) | number4
The random generator is called three times.
rand1 = random(seedval)
seedval = rand1;
rand2 = random(seedval);
seedval = rand2;
rand3 = random(seedval);
seedval = rand3;
The three random values are used to select one of the three DSP functions.
E.g. Rand1 controls where the first section comes from.
How can I use it?
Its important that before you do anything that you SAVE everything in RAM.
For users who leave there machine on continuously and do not ever turn it off, its recommended that you do turn it off after you have finished experimenting with this feature. This will allow the K2 to return to its normal state.
Start by constructing a 1 LAYER PROGRAM using ALGORITHM 8.
On the GAIN page, set the “Adjust:” parameter to 0dB.
Assign the Mod Wheel (Mwheel) to "Src1".
Set the "Depth" to -96db.
On the ALLPASS page, set the “Coarse:” parameter to its minimum.
Assign the Data Slider (Data) to "Src1:".
Set the “Depth:” to its maximum value.
Set the Keymap to "163 Sine Wave." (K2000)
Now save the PROGRAM.
This is the “template” that you will use for the random DSP generator.
Now press the MASTER button.
Now press the UTIL button.
Press the blank soft button. Make sure the Modulation Wheel is all the way down and the DATA slider is in the middle position.
Now press the EFFECTS button.
Each time you press it, the Kurzweil generates random DSP functions instead of the normal Allpass filter. Most of these will be pretty unusable, but by pressing it enough times, you will find some that make sound, maybe even sound interesting. Of these the majority will be some type of LOUD distortion. By moving the data slider, you will hear the effect of varying the DSP's coefficient, sometimes interesting. By moving the mod wheel, you will hear the effect of lowering the gain before the DSP, often interesting on distortion types of DSPs.
When you find something you like:Press the QA button.
The Kurzweil will tell you a 4 digit number that you can write down, to get back to that DSP. After you write down the number, press OK. The Kurzweil will prompt you to enter a previously obtained number. You can either enter the four numbers or press OK twice to cancel. In summary, the QA button lets you either read the current randomly generated numbers or enter numbers that you want (or both).
Pressing the EFFECTS button randomly generates DSP instructions for the Allpass function, starting from the last numbers you entered, or from 0 after power up or a soft reset. You can start a session by entering previously obtained numbers, because otherwise you are likely to cover the same ground as you did previously.
Another idea is to start a session by entering 4 arbitrary numbers - that way each session searches a different space. Also try other keymaps, you can get good results with samples that have a lot of high frequency content.
One thing you will notice is that if you do this, any other programs which use the Allpass DSP will be completely screwed up until the numbers are set back to 0 (which happens each time you turn on the unit, so you can't permanently screw up those programs).
Here are two examples that make noise with the template program:
140-168-238-108 (hold chords and move slider)
126-173-28-236 (really distorted when more than one note played)
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