Stacker: Triple Quadrilateral Key Generator

Check out Stacker and some updates to our website here:

Stacker will fill an interesting niche in a lot of systems – and 3x quadrilaterals in 8HP provides a big impact with tools like Angles, DSG3 and DWO3. I think of it kind of like a tool to generate mosaic fragments.

How do you modulate it?! Mixers and VCAs before the HV inputs. For example, Proc would give you voltage controlled XY position, if a CV or bias is applied before a ramp is then patched to Stacker. We have some motion control modules planned that will fill this role well.

Excited to discuss.


I like the new site look. Nice!

And another module for my ‘gotta have it’ list.


I don’t quite get how it works or how it differs from a Keychain, but it still seems neat. I guess I need a @Johnnywoods video about it.


Keychain has one threshold (hard keyer), Ribbons has two thresholds (hard window keyer), Stacker has four thresholds (hard quadrilateral keyer).


Thanks. That definitely helps.

I’m still curious a bit about how it does it under the hood. Is what it does the same as if I patched up some modules to get the same effect from an h and v ramp input (mirroring the ramps, adding them together or whatever, then keying)? Or is it different than that? I’m trying to understand how it changes arbitrary inputs.

Actually now that I think about it, I’m not sure I can get a shape that when keyed makes a rectangle (instead of a diamond) out of the DSG. I feel like I’ve done that in my system before but I’m not sure how. I’ll have to play around and see, that might help me grasp this.


Dave Jones’ wonderful guide to making shapes from ramps rears its head again!

Yes, the most efficient way to get a keyed square with discrete functions is frequency doubling (mirroring) your H and V ramps to get triangle waveforms, then hard keying each triangle ramp separately and lastly combining those two signals with a logical AND / maximum. The last step could also be done by summing your two keyed triangle ramps with a mixer and then hard keying them one more time. The brightest area where the two overlap is where you want to set your threshold.

You could gain additional control of the bounds of your keyed square by not frequency doubling the ramps but adding additional hard keyer stages and logical AND / maximum (or summing + additional hard key). This is basically window keying so that you can independently set the left / right bounds of the H ramp and top / bottom bounds of the V ramp.

EDIT: Replaced the incorrect ORs with correct ANDs, whoops.


Wonderful! That clears it up perfectly for me! Thanks so much @rempesm! That helps me better understand what’s going on in those demos videos.


I’ve just uploaded an “unboxing” video for the new-ish Stacker to Youtube. It’s 8 minutes long but it’s colourful and the last 3 minutes are where the real patching begins, I was pleasantly surprised.

After making the video, I patched Diver into it and that was cool.

The surprising (describing it as an easter egg is a bit far but :-)) feature I stumbled across is the cascaded inputs, meaning having only the top row of 2 inputs used led to differing signals from all 3 outputs.

Thanks to the RAW VOLTAGE shop in Vienna for stocking LZX & other videosynth modules here in Europe.