4 way CV switcher and stereo toggleswitch

A while ago I was trying very complicated CV set ups just to get a toggleswitch that would choose one signal path exclusively. I wanted each button, to turn on one route while muting all other routes. I gave up. The toggleswitch plug-in doesn’t actually “toggle”.

Then today I noticed a CV switcher, and yeah, that does exactly what I wanted to do - in fact it might be the only way to do what I wanted to do.

So my request is to have a stereo version of the toggleswitch plug-in, and a CV switcher with 4 routes - you can see that it’s a perfect match !


I also wanted to have a simple toggle switch and thought I missed something. And I did indeed – the CV switcher is the tool I was looking for. Thanks for sharing!

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Have you tried the utility “Switch Trigger 4”? It’s a proper switch to assign one audio signal to 4 different routes. It is mono; for stereo, you could use two units and create CV ‘meta’ buttons to switch both units parallel.


From what I can see Switch Trigger 4 is momentary. So it doesn’t quite do what I want. I am really looking for a toggle switch where only one can be on at at time.

That is what switch trigger does, it is a trigger, not momentary.

Thanks for the info - I will retest this.
The graphic for the Switch Trigger 4 makes the switches look momentary - ie: they don’t stay punched. I will test what it actually does though.


I just re-checked Switch Trigger 4 - and yeah, it isn’t momentary, but if I assign the four buttons to the four switches, there is no visual feedback. The buttons change color (momentarily btw :grinning:), but the LCD indicator does not light up which channel has been selected. Might be fine for an external control device.

Using the CV switchbox is great, because you can assign it to one of the endless encoders, and clearly scroll through the channels, with visual indication of what channel you are on. Also only needs that one encoder - not four whole buttons. But yeah, a 4 channel switchbox would be excellent!


I might be wrong, but I think there is a short flash of red light on a duox when a trigger-type parameter is changed.
The reason for the odd behaviour is because by core standards, an lv2 plugin cannot change its own parameters. So we were unable to make it so that enabling output 1 would disable output 2. The way to go around this is to make 4 triggers (they get automatically reverted to their default position after 1 audio cycle).
We added a custom lv2 extension in v1.10 to break free from that “plugin cant change its own parameters” restriction, so going forward it now possible to get a plugin that actually shows the state as the user expects; and that switching a different output would turn off the other ones, we can even make this optional on/off behaviour.

TL;DR there was a limitation in our system and SwitchTrigger4 was the best that could be done, but no longer the case in v1.10 onwards.

So we can add this to our backlog - a switch-toggle-4 plugin.

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We added a custom lv2 extension in v1.10 to break free from that “plugin cant change its own parameters” restriction

How does the LV2 ecosystem work in this regard? Is it possible to get this into the LV2 standard, or is there an upstream extension repository? Or will it be a MOD-only extension?

Right now we went with a custom extension I made. It is not MOD specific, any other host can add it.
The relevant discussion is at Writing to control input ports w/o UI (DSP -> host; via atom output port) - RFC by rncbc · Pull Request #42 · lv2/lv2 · GitHub


Just curious, is adding a fourth output to the CV Switchbox an easy thing to do? Just wondering if the three outputs was arbitrary or related to some standard/limitation?

More of an UI thing than anything, I would say. it is pretty arbitrary, “3 outputs should be enough for everybody” kind of mindset.

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So I’ve shared a pedalboard to show how I am using a single knob to select one of four channels. Possibly this is obvious to everyone, but it wasn’t to me. The key was to not have the knob control the voltage, but to select presets. This way, you can name your presets “01 channel one, 02 channel two” etc.

I like having one knob for a function - and having names for what the knob does makes this a far superior option than my original switchbox solution.

This new solution, could have many more ‘presets’ if you want, four is not the limit.


I’m still using complex CV set ups to allow a single knob to select one of four channels. Have there been any new channel switchers, or togglers added to the plug-in library which would make this simpler?

If I’m correct, since the last time you asked about it there were new switch plugins or similar being add on the platform.
Recently the developers have been more focused on overall OS improvements. Anyway keep an eye on the plugin list :wink:

Something I would use a lot in my pedalboards is the opposite of a crossfader.
Something that would allow me to smoothy send a signal to A or B destination, and 50% in between.

Basically the opposite of this:

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I currently use a workaround, with two Volume2x2’s with a Control to CV and a CV modulation. so one knob makes each Vol plug-in go in the opposite direction.

For mixing, it works, but I assume replacing 4 plug-ins with 1 would reduce CPU.


Saved on requests. Anyway, let me tell you that CV plugins normally don’t use much CPU, as simple logic plugins.
And…Can’t the Mixer plugin help you on this?

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Glad to know the CV plug-ins use little CPU.

The mixer plug-in does not have a single knob I can assign which will smoothly transition between two destinations. There are no plug-ins with this feature, only ones that go 100% A or B destinations.

I could set up the mixer with two CV plug-ins, but that only reduces my use from 4 simple plug-ins to 3 plug-ins with one being a mixer which is likely more CPU than a simple volume plug-in.

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Eventually, if we get less overwhelmed and there’s a big demand we will put it for development.