Wish Pedal as modifier : cycle through values more than once

[fractalz]

This one is a bit tricky to explain, but could be very useful.

Currently, the modifiers cycle through a set of values, by default 0% to 100% once representing full travel of an attached expression pedal.

What I would like is to have this cycle repeat N number of times with a phase offset.

Why? I have multiple parameters that I want to mix together and I want to do this in a way that produces all combinations as the pedal moves from one end to the other. One way to think about this would be cycling through all the options to create a BW image from a color image with a single slider (um, like, maybe, like, some Apple products...). You can construct sinusoidialish curves with different frequency and phase representing each parameter and parameterize it in such a way that you actually hit all combinations with one control.

I'd like to do this with an organ patch I've created that has 8 virtual "drawbars". I want to cycle through all the combinations (or, many combinations) with one expression pedal.

 

[unix-guy]

So the curve of your modifier would be a sine wave with a "frequency" that subdivides the midi values 0-127 evenly as the sweep moves from min to max?

Kind of like a manually controlled LFO...

Interesting idea. Would be cool to allow various wave shapes like triangle, saw up, saw down, pulse...

 

[Rex]

I have multiple parameters that I want to mix together and I want to do this in a way that produces all combinations as the pedal moves from one end to the other.

It's that "all combinations" part that's kind of a deal killer. MIDI CCs give you 128 possible values. If you only have three parameters you want to work with, that's 2 million possible combinations. But you only have 128 pedal positions to choose from. You'd have to throw away near all of the two million combinations.

If you only have five possible values for each parameter, you've just eaten up 125 of your 128 positions. There would be clearly-audible steps between each of those positions. Sweeping the pedal would sound like a zipper closing. I can't think of a practical use for that, and I wouldn't want to have to choose a setting that way. You'd have to be able to accurately position your pedal within 1/128th if its sweep.

 

[fractalz]

It's that "all combinations" part that's kind of a deal killer. MIDI CCs give you 128 possible values. If you only have three parameters you want to work with, that's 2 million possible combinations. But you only have 128 pedal positions to choose from. You'd have to throw away near all of the two million combinations.

If you only have five possible values for each parameter, you've just eaten up 125 of your 128 positions. There would be clearly-audible steps between each of those positions. Sweeping the pedal would sound like a zipper closing. I can't think of a practical use for that, and I wouldn't want to have to choose a setting that way. You'd have to be able to accurately position your pedal within 1/128th if its sweep.

I assume the axe is interpolating the pedal to come up with values for the knobs. This is similar to other uses where you would dial up gain but lower master volume to keep an even level. I my case, pull out drawbar 4 but push in drawbar 5 faster... Each of the "drawbars" are a voice in a quad shift and I'd be automating the level parameter.

 

[fractalz]

I assume the axe is interpolating the pedal to come up with values for the knobs. This is similar to other uses where you would dial up gain but lower master volume to keep an even level. I my case, pull out drawbar 4 but push in drawbar 5 faster...

So the curve of your modifier would be a sine wave with a "frequency" that subdivides the midi values 0-127 evenly as the sweep moves from min to max?

Kind of like a manually controlled LFO...

Interesting idea. Would be cool to allow various wave shapes like triangle, saw up, saw down, pulse...

Right. For a simpler example, take a V shape. As the pedal moves from 0-127, the values go from

100% -> 0% -> 100%

If another modifier used W shape, it'd go through this cycle instead:

100% -> 0% -> 100% -> 0% -> 100%

So, you'd get a bunch of combinations. To cover the entire set of combinations you need more complicated curves, but this is the general idea.

 

[Rex]

I assume the axe is interpolating the pedal to come up with values for the knobs.

MIDI is MIDI. You only get 128 values. There's no room for interpolation. When you send a value of 43, the Axe can't determine whether you really meant 43.5 or 42.5.

Your example of one parameter with a V shape and second parameter with a W shape might be practical. If you throw in a third parameter, things could get pretty hairy to control.

 

[fractalz]

MIDI is MIDI. You only get 128 values. There's no room for interpolation. When you send a value of 43, the Axe can't determine whether you really meant 43.5 or 42.5.

Your example of one parameter with a V shape and second parameter with a W shape might be practical. If you throw in a third parameter, things could get pretty hairy to control.

What I mean is that the pedal input is continuous. The midi value sent can go from 0-127 just the same in a V or W and use the full midi dynamic range.

 

[Rex]

What I mean is that the pedal input is continuous. The midi value sent can go from 0-127 just the same in a V or W and use the full midi dynamic range.

That's true.

The tricky part is when you try to mix a V shape and a W shape. As you sweep the pedal, the V-shaped parameter drops by one CC value, but the W-shaped parameter has to drop by two values to keep up. Throw in a third parameter, and that one has to drop by 4 values to keep up.

 

[Bakerman]

That's true.

The tricky part is when you try to mix a V shape and a W shape. As you sweep the pedal, the V-shaped parameter drops by one CC value, but the W-shaped parameter has to drop by two values to keep up. Throw in a third parameter, and that one has to drop by 4 values to keep up.

You'd be limited to 128 resting values with MIDI CC (Axe II pedal ports have 1024-step resolution IIRC; maybe this is the case for III/FC pedal ports) but a little modifier damping should prevent any zipper noise.

Something kind of like this can be set up now (with various limitations) by chaining modifiers together in a certain way. For example (use FracPad) assign a pedal to scene controller 1 with an arched 0-100-0 shape. Now assign SC1 to SC2 with the same modifier shape. When the pedal goes 0-100%, SC1 goes 0-100-0 and SC2 goes 0-100-0-100-0. More scene controllers can be used, and a stopped LFO or sequencer (step 1 value) works too. On the Axe II the Manual ABCD knobs also work. Different modifier shapes can accomplish things other than just doubling the amount of travel with each step, for example 0-100-75 gets 1.5x the movement.