Exponential scale for parameters

We have the option to use a logarithmic scale LV2 Port Properties.
But I would like to have more control over the curve of a parameter actually. Changing the exponent would give way more control over the range of a knob. Is this at all possible? Through a workaround or the actually lv2 api.

This is not possible, not at the moment anyway.
My recommendation is to use a generic parameter (say 0-1 value range or 0-100%) and do an internal exp curve on the plugin side.

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Too bad, thanks for confirming it’s not possible.

I wanted an exponential scale for a time parameter. For that use case it doesn’t make sense to use a generic parameter in the range of 0 to 1. You want to see the time that’s being set. But I’ll stick to linear or logarithmic, see what fits best.

Couldn’t this theoretically be possible through javascript though? I think it would be very useful to be able to direct users to a more convenient range of a knob. To regions where you get the most “useful”/interesting sounds. And to have more musical results when sweeping the parameter. Using a generic parameter is a solution but has the downside that you have a lack of visual feedback. And you’re not able to set a parameter to a specific value. I expected this kind of parameter mapping to be common for lv2 plugin development too.

But I can’t oversee what the impact of applying a curve on the javascript side would have on the whole system. I can imagine it needs to be managed by the plugin, not the ui.

I’m fine taking “not possible” for an answer by the way. I am just thinking out loud :slight_smile:

No, we can never assume as web browser to be connected or open at any time. Changing a knob is just not something possible only via the web gui but also via assignments of MIDI CC, Control Chain or the Dwarf hardware knobs.

One thing you can do though is to add LV2 scale points to individual values.
so that 0 = “off”, 0.15 = “type A” and 0.25 = “type B” for example.
that value is not shown on control chain or the device hardware knobs, but it appears on the web gui.

maybe it could be possible using CV and developing a plugin something similar to Attenuverter Booster which performs power instead of multiplication

Alright, all makes sense. I’ll make do with the way things are. I’ll see if I can send a feature request to the lv2 maintainers though.