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Re: 3 Way Wavetables.

Posted: Mon Dec 06, 2010 4:36 am
by CBK81
I can think of q few different ways to do this in alchemy. The most obvious would be to assign the osc mix to the 8 scene performer grid. Another would be to make samples of your wave forms and modulate the start point of the samples.

Re: 3 Way Wavetables.

Posted: Fri Dec 10, 2010 12:51 am
by 3za
Just a little update;

I have found out that my idea of a 3d wavetable, is not unique. It is called a, "3d wave terrain synthesis" this idea has been about for some years, but it seems there has yet to be a decent Implementation of it.
dsp wiki wrote: Wave Terrain Synthesis
Also called two-variable function synthesis, it extends the principle of wavetable lookup to the scanning of three-dimensional wave terrains (WT). A scan over the terrain is called an orbit, and can consist of any sequence of points on the wave terrain. If the orbit repeats itself (is periodic), so will the output signal. Varying the orbit over time generates time varying waveforms.
Even more geeky stuff can be found at these links;
http://academic.konfuzo.net/publication ... 99-SBC.pdf
http://csounds.com/jmc/Articles/Wts/WTS.html
http://www.wiard.com/terrain/terrain.html

And even more geeky stuff here;
http://adt.ecu.edu.au/adt-public/adt-EC ... amesSG.pdf
http://adt.ecu.edu.au/adt-public/adt-EC ... amesSG.pdf

Anyway the idea is out their, it just needs lots of work.

Re: 3 Way Wavetables.

Posted: Fri Dec 10, 2010 1:18 am
by staticcast
3za wrote:Just a little update;

I have found out that my idea of a 3d wavetable, is not unique. It is called a, "3d wave terrain synthesis" this idea has been about for some years, but it seems there has yet to be a decent Implementation of it.
dsp wiki wrote: Wave Terrain Synthesis
Also called two-variable function synthesis, it extends the principle of wavetable lookup to the scanning of three-dimensional wave terrains (WT). A scan over the terrain is called an orbit, and can consist of any sequence of points on the wave terrain. If the orbit repeats itself (is periodic), so will the output signal. Varying the orbit over time generates time varying waveforms.
Even more geeky stuff can be found at these links;
http://academic.konfuzo.net/publication ... 99-SBC.pdf
http://csounds.com/jmc/Articles/Wts/WTS.html
http://www.wiard.com/terrain/terrain.html

And even more geeky stuff here;
http://adt.ecu.edu.au/adt-public/adt-EC ... amesSG.pdf
http://adt.ecu.edu.au/adt-public/adt-EC ... amesSG.pdf

Anyway the idea is out their, it just needs lots of work.
Actually, the technique above is a 2d wavetable. You're driving around this 2d surface - that is, you can control your longitude and latitude - and the height of the land is the output.

A standard wavetable is like a normal graph - you can control where you are on the x-axis, and the y-axis is the output.

A 3d wavetable would be more like... umm... a gas tank full of (stationary) smoke in a funny marbled pattern, where you move around the tank (you can control longitude, latitude and height) and the "result" is the opacity of the smoke at that point.

I'm not sure if a synth with a 3d wavetable exists. How feasible it is depends on how the wavetables morph into one another. If it's simply crossfading, then a 3d wavetable would not be complicated to implement at all and is basically tantamount to using a 3 oscillator synth and controlling the level of each. That wouldn't really be very exciting and you can rig up most synths with some kind of X-Y MIDI control to fade between oscillators. However, take the case of Massive. The wavetable position knob doesn't just crossfade between two wave shapes... in the more complex wavetables it's actually crossfading through many more (I think there are up to a hundred nodes or something like that, but I'd have to check). This is necessary in order to create interesting "morph" effects, otherwise it just sounds like, well, crossfading.

Now, if you have two axes instead of one, you could end up with that number, squared - so a hundred wavetables on one axis, a hundred on the other - that's 10,000 wavetables for one oscillator. Each of those being a few hundred samples, or more.

And even a "single" wavetable - no morphing - isn't as simple as it seems. Digital synth developers always need to avoid aliasing somehow, and with wavetable synths that often means using a different table (containing fewer or more harmonics) depending on which note on the keyboard is played. This means that even a single wavetable synth could actually be using several wavetables "under the hood".

To cut a long story short, to do it properly would take up rather a lot of memory and CPU. Of course, if you just want to fade between 3 wave shapes, you can just use a synth with 3 oscillators and adjust the level of each.

Re: 3 Way Wavetables.

Posted: Fri Dec 10, 2010 3:07 pm
by 3za
^^^^^^
Thanks for the reply.

Yeah your right that quote describes a 2d wt.

Re: 3d Wave Terrain Synthesis

Posted: Sat Dec 11, 2010 12:18 am
by 3za
I got a bit excited when I posted about wave terrain synthesis, on second thought I don't think this is what I was originally looking for. Even thought I like the idea of it.

My original idea, was of a cube made of lots of little tiny cubes, each of which is a different waveform, and you would be able to crossfade in to adjacent cubes. Am I right in think this is different to wave terrain synthesis?

Re: 3d Wave Terrain Synthesis???

Posted: Sat Dec 11, 2010 1:16 am
by drake89
If you want to use the wii-mote as an xyz controller, you can do it. You need the light bar to reference for xy movement but the accelerometer inside the remote reads the z axis.

But I'm pretty sure you'd have to be quite handy with computer programing to pull that off as a good synth modulator. Make friends with nerds? Or BECOME ONE muahaha