Confused about wavetables

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Hi Guys

I'm afraid I just don't understand the wavetable functionality, and studying the manual isn't helping me.

I know I'm being stupid as I can't see anybody else asking about this, but what I don't understand is how to loop through the 16 waveforms, controlling their rate, and their amplitude.

I have a test setup in Zebralette, with a triangle wave at position(p) 1, a square at p5, a sine at p9, and a sawtooth at p13. In all other slots I have a flat line at 0.

I have been messing around with modulating the waveform section with the global LFO, and with drawing envelopes in MSEG, and varying the resolution, and piping the results through an oscilloscope to see what is happening to the waveforms.

With pretty much everything I do (eg messing with the LFO time, and varying the resolution OR drawing a long curve across multiple points in MSEG). I get a preponderance of the triangle wave at p1, and it is noticeably bigger in amplitude and longer in duration than the other three waves (which I can scan through using the global LFO).

I know that I really don't have a clue what I'm doing here, but might be able to figure it out if some kind person could answer me a couple of questions:

1. What settings would I need to loop through my 4 waveforms at say 1 Hz or 2 Hz and have them each appear at equal amplitude and equal duration?

2. When trying to loop through and control the rate and amplitude of the waveforms, how do I use the envelopes in MSEG?

Or have I just totally got the wrong end of the stick concerning the functionality of this feature of the synthesiser?

Confused (as you can see!)

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Ooooph...

It's hard to answer this without a lot of screenshots, but here we go:

First of all, set the Osc mode to "GeoBlend" and draw your desired waveforms on adjacent slots:

1 Triangle
2 Square
3 Sine
4 Sawtooth

You can use Option-drag (Mac), ctrl-drag (PC) to move the little wavetable overviews around...

Then, for LFO modulation (which is bipolar, between -1 and +1), set

Wave to 2.50 (center between Square and Sine)
Wave Modulation Depth to 1.50

For MSEG modulation (which is unipolar, between 0 and +1), set

Wave to 1.00 (Triangle)
Wave Modulation Depth to 3.00

The important thing is, there shall be no "gaps" between the wavetables.

Now about volume: If the Normalize Parameter is set to zero, all waveforms have the volume they're drawn in. If Normalize is set to 100%, all waveforms *sound* same volume (same RMS level)

And... don't put "Resolution" below 5.00, otherwise you won't have smooth transistions.

Hope this helps for now...

Cheers,

;) Urs

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Urs wrote:Ooooph...

It's hard to answer this without a lot of screenshots, but here we go:
Hi Urs, thanks for replying, but did not want to waste your time with this.

First of all, set the Osc mode to "GeoBlend" and draw your desired waveforms on adjacent slots:

1 Triangle
2 Square
3 Sine
4 Sawtooth

You can use Option-drag (Mac), ctrl-drag (PC) to move the little wavetable overviews around...
I knew I should have gone to art school :)

Then, for LFO modulation (which is bipolar, between -1 and +1), set

Wave to 2.50 (center between Square and Sine)
Wave Modulation Depth to 1.50
I'm not sure what the 'wave' parameter is? I can select waves but not set a value?

For MSEG modulation (which is unipolar, between 0 and +1), set

Wave to 1.00 (Triangle)
Wave Modulation Depth to 3.00
OK, notwithstanding the 'wave' parameter, I just don't have a clue what sort of curve i should be drawing here.

I'm trying to understand what is going on with the wavetables, and perhaps I should be more general.

How do I choose how many waveforms out of the 16 will be cycled through?

How do i choose the rate at which they will be cycled through?

Why do I see other people's patches starting at Pn rather than P1?

Sorry, but I really am totally lost. I just don't have a clue how all this works at all.

Thanks for trying :)

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Ah... okay... now I understand...

Here's the short answer:

In Zebra2, wavetables are not cycled through automatically.

Each osc has 16 wavetables, but you need LFOs, envelopes, whatsoever to run through them...

I'll make a sample patch, but gotta install drivers first...

;) Urs

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Okay, installed my drivers for the usb-midi-keyboard, made a patch and... here's it:

www.u-he.com/wavetabledemo.h2p (right-click and save to disc)

Works in Zebra and in Zebralette
Has your 4 waveforms morphed as either GeoMorph (spline based morphing) or GeoBlend (wavetable)

The wavetable modulation occurrs on LFO

Note: Unlike many other synthesizers, the transitions are usually pretty smooth... no audible steps...

Hope this helps,

;) Urs

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Urs wrote:Ah... okay... now I understand...

Here's the short answer:

In Zebra2, wavetables are not cycled through automatically.

Each osc has 16 wavetables, but you need LFOs, envelopes, whatsoever to run through them...
:) I'd figured that much out, my test case was just an attempt to understand exactly what was going on, and kind of 'deduct' the rules from that. :)



I'll make a sample patch, but gotta install drivers first...

;) Urs
Cheers Urs. No worries and no hurry at all.

EDIT: your patch arrived while i was posting this. Just checking it out. Cheers :)
Last edited by lnikj on Wed Oct 25, 2006 7:38 pm, edited 1 time in total.

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on a side note, whilst we are on the wavetable topic... :D

is it normal that the copy/paste wave function only copies the breakpoints and their position, and not the curve data in between?

thanks!

ps. forgot to mention i'm using the osX UB in logic and live.

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beatz wrote:is it normal that the copy/paste wave function only copies the breakpoints and their position, and not the curve data in between?
No. Copy/Paste copies all 16 wavetables, i.e. from one osc to another...

To copy a wavetable from one slot to the next, there's a modifier key... can't remember exactly... look here (paragraph "waveform selector"):

http://www.u-he.com/zebra/manual/?page_id=7

;) Urs

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Urs wrote:Okay, installed my drivers for the usb-midi-keyboard, made a patch and... here's it:

www.u-he.com/wavetabledemo.h2p (right-click and save to disc)

;) Urs
My ignorance knows no bounds probably but I cannot get that file to show up in the preset browser of either the au or vst version of either synth on my mac. I have checked extension, permissions etc, tried sticking it in the root preset folder, another folder, a newly created folder etc, but nada.

Sorry :(

EDIT: Sorry, restarting host solved it. Thank you for your patience :(

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Urs, you're a genius 8)

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Thanks for the patch Urs, but I'm afraid there is still something missing in my understanding.

The patch had P3, the sine wave, preselected. This seems to exhibit an even cycling throug the 4 waveforms, which is what I asked for.

However if I start at P1, the triangle, it sustains the triangle for a long time and then cycles through the the other waveforms.

If I start at P2 or P4, I get a very brief burst of the square or sawtooth and then it starts cycling immediately.

Still a bit lost I'm afraid. What is the significance of the starting position?

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There are 16 waves. Which one is active depends on the waves knob for each oscillator. At zero, you are listening to wave 1, and the further you turn it, the waveform moves through each of the 16 slots in turn, morphing as it goes (if you are using oe of the morph modes).

So, as turning the waves knob moves through the wavetable, in order to do this automatically, you have to set up some kind of modulation source to effectively "turn the knob" for you. If you use an LFO as a mod source, the waves will oscillate according to the speed, depth and waveform of the LFO.

If you want really controlled waveset modulation, you could use a custom LFO waveshape, or one of the multistage looping envelopes to control the waves.
Image

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Oh...

You have to distinguish between two things:

Editing a waveform
Playing stuff

The whole modulation is relative to the selected waveform. Selecting a waveform is pretty much the same as changing the "center" of the modulation. - when clicking in the small waveform previews, you actually do the same as turning the Wave knob. Just, the Wave knob can be turned not just in whole numbers (1.00, 2.00, 3.00...), but also "inbetween" two wavetables.

When you edit a waveform, you usually do so without any modulation, because only then you can actually *hear* what you are editing. Then, after you have edited your waveforms, you start adding modulations.

I had thought about splitting these, so that modulation is automatically disabled while editing. But I concluded that this would be even more confusing than the current way.

Hope this makes it a bit more clear...

;) Urs

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Thanks beej, but why does the waveform at P1 sustain much longer than if it is started at Pn?

Sorry if I am being thick.

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Clear and useful explanation beej! :tu:
The more I hang around at KVR the less music I make.

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