wave draw output interpolation is an issue

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wave draw output interpolation is an issue

Postby dutchound on Sun Dec 11, 2011 3:43 pm

The wave draw could be used as an amazing drawable envelope to modulate LFO speed, LFO amplitude, FM, effects ... and literally sculpt sound pads.

But there is a major limitiation in the "wave table read" module, it averages and changes all the values in the array to adjust them between -1 and -1. it would be lovely to have a second output on "wave table read" module that bypasses the interpolation and just puts out the straight values that are in the array, and then it would be possible to use this wave draw as a modulation source.

I have a nice prototype synth that sculpts pads from many oscillators and effects using a drawable envelope i want to make it in SM!
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Re: wave draw output interpolation is an issue

Postby cyto on Sun Dec 11, 2011 8:27 pm

Using the "wavetable read" primitive is probably not the best idea in this situation. Wavetables are special data tables that have the array represented for many different situations to handle anti-aliasing for different frequency values. They are not just simple data arrays.

Instead, try using the "wave read" primitive. You can load any arrays into a memory buffer and feed that to the "wave read" primitive. As far as I know (though I haven't tested this out), the "array to mem" primitive does not scale the data to -1to1 nor does the "wave read" primitive require -1to1 values. Test it out for yourself. You will need to construct some kind of "counter" module as well. If you need help, I can upload an example.

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Re: wave draw output interpolation is an issue

Postby dutchound on Mon Dec 12, 2011 11:32 pm

thanks! would i have to make a green signal counter because the input of the wave read is a green line? and so in that case would it be possible to have in polyphonic and sync'd to the midi input? i tried to see how to do as you say but i felt way out of my depth, i didnt really understand the wave read module's inputs.

also it might be easier to make a workaround by adding all the values of the array together, take the average value and add it to the "wave table read" module output to bring the signal back to it's original range? could you tell me how to find the average figure for all the values in a SM array?

The anti-aliasing effects could be unnoticeable as-is because it is for use as a LFO without HF's, although i dont know ???.

Thankyou!
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Re: wave draw output interpolation is an issue

Postby dutchound on Tue Dec 13, 2011 1:55 am

HOLD YOUR HORSES!

my mistake i found a solution!! it wasnt the wave table read module that was messing up the values from the array! no one said me that!

there cleverly is a green DC value on the Table module!!! it sais "preserve the DC instead of making it zero" and this is what was messing the array values! so i set it to true, and the stock Wave Read macro is totally useable as an LFO just by changing the table DC!

here is the example, i am so happy i have this draw envelope :)
Attachments
wave read mod env with f control.osm
(172.58 KiB) Downloaded 237 times
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Re: wave draw output interpolation is an issue

Postby cyto on Tue Dec 13, 2011 2:34 am

dutchound wrote:HOLD YOUR HORSES!

Doh! the horses were already running while you were posting that ;)

Here's the promised example of how to use the wave read primitives...
wavReadExamples.osm
(77.63 KiB) Downloaded 257 times

Maybe you can glean some more insight from them. I also expanded the idea to show you how to implement envelopes using this technique (I seem to remember reading some posts of yours recently hinting at maybe doing that). These are not fully fleshed out solutions but should nudge you in the right direction.

You do need to keep in mind that "wavetables" are not the same thing as waves. I'm not 100% sure how SM handles wavetables, but traditionally they are literally tables of many individual single-cycle versions of the wave that are inter-modulated in response to the frequency requirements. To that end, if you continue to go down this path, you may find that they will not always work as would be expected if it were simply an array representation of the values of a single wave cycle.

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Re: wave draw output interpolation is an issue

Postby dutchound on Mon Dec 19, 2011 7:01 am

Hey thanks Cyto!

That will really help me (and others!) to learn because it is a very well done example, i can understand that! Sorry i was kindof wrapped up in making my synth i didnt see it! thanks so much!
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