Best way to make a matrix switch with cv -- not gate -- control

I asked about sequential switches before.

I have four ins that I want to route – in sixteen ways – to the four outs, based on an incoming cv that has sixteen settings (0 to 8 volts, so in increments of 0.5).

Hope that makes sense

Just ON/OFF control of 16 nodes? Make a truth table for your matrix and use Bump Scanner units to satisfy those conditions.


Unfortunately, I can’t code.

Just to clarify: when cv is zero, have no audio outs; when cv is 0.5, send input1 and input2 to output1, and input1 and input3 to output2; when cv is 1 send input2 to output1, and input4 to output3… etc. or any combination given any cv input.

A truth table’s not code, it’s just a chart for organizing output states based on inputs. You’re describing one right now! It’s an important start because there are actually 65536 possible combinations of outputs for a simple 4x4 matrix and no one but you knows which 16 of those combos are useful to your application.

I took what you said above and turned it into the start of a truth table. You will want to organize your states such that each column only has one group of ones to make Bump Scanners viable (EDIT: or if you end up with multiple groups of ones, you can use Mixers to mix together multiple Bump Scanners for your logic).


I’m not seeing how that helps me decide what units to use?

m’kay well it’s gonna be VCAs, Bump Scanners, and Mixers. A bunch of them. But maybe I can’t help you if you can’t see the value in defining the precise behavior of your matrix switch.

(edit to note that you can use a Bump Scanner as a VCA if you’re clever)

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Maybe I’m being too harsh, sorry. But you will have difficulty approaching the problem at a detailed level if you don’t have some sort of map. This is, after all, a question of mapping: you want to map your output combos to very particular ranges of CV inputs. The Bump Scanner unit lets you define the boundaries of each of these CV ranges. Using the Bump Scanner output to control a VCA will define the switch behavior for that node of your matrix.

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OK well I was asking about how – the best and easiest way – to do it, not how to think about the result. I understand the need for VCA and Mixers (16 of each), but not the bump scanner? I was thinking about using a voltage bank on the cv in, so that each of its steps is set as on or off. But it would take a while to set that up – each of the 16 mixers having 16 different settings to program.


You’re inevitably going to have a lot of setup in order to achieve 16 unique mixes. Voltage Bank is a good idea but I think it only goes up to 8 elements. If you are ok with making your outputs symmetrical in some fashion then 8 elements per node might be enough?

Bump Scanner can be configured to output a high state (i.e. switch closed) within just a particular range of input voltages. So if you are able to make it so every switch in your matrix is only engaged within a single voltage range then you can make your switch matrix more efficiently.


8 elements is enough.

I used voltage bank; the CPU is at 80 percent (was expecting more like 70) for three outputs and four inputs.

So, it worked and is easy to update. Do you think using bump scan would be more CPU friendly??