Blinds: Controlling Control Voltages

For a VCA, Blinds isn’t the first module I’d look into but, if you’re running a small system, it’s one of the best…

I don’t feel a huge need for function per hp in modules. I prefer a good set of functions and good ergonomics. But, blinds has it all. At 3hp per channel (12hp total) you get attenuation, offset, polarization, VCA, ring modulation, and mixing capabilities. All of these are wonderful, but today we are going to focus in on three fundamental tools for control voltage manipulation. Tools which can be easy to overlook. They are not sexy, but they are incredibly powerful. They are true force-multipliers for any modulation source. They are attenuation, offset and inversion.

Attenuation: Amount/Depth of modulation
Offset: Center of modulation
Inversion: Direction of modulation

Attenuation is a basic function of reducing the amplitude of a voltage. For example just plugging an LFO into our filter cutoff can produce a huge range of modulation, from wide open to completely closed. But what if we’d rather just move it around a bit? By using a simple attenuator we can dial in the amount of modulation until it’s just right. We can have modulation ranging from almost wide open to hardly any at all. Similarly sometimes an ADSR might have a bit too much bite to the attack. The speed is right, but just too much. Again, attenuation to the rescue. Attenuation is not a “sexy” function. But it is a vital tool for control voltages.

Offset: An offset voltage is a simple static voltage. Sometimes, we may want to bring the value on an input up or down a bit, or just hold open a gate. An offset voltage can handle that all by itself. But what if we add an offset voltage to a modulation source? Lets go back to our LFO. We have the amount of modulation dialed in with our attenuator, but with it wobbling around a 0V center point it’s just not getting the job done. With an offset voltage we can move its center-point up (or down if its a bi-polar offset). Similarly, you can use an offset voltage to alter the base-line voltage for an envelope.

Inversion: Inverting a signal reverses its polarity, from positive to negative (or the other way around). Increasing voltages will become decreasing voltages, and decreasing voltages will become increasing voltages. Now, in general with LFO’s this is a non issue. But sometimes when you’re combining LFOs or sending out multiples of the same LFO, inversion can help prevent phase issues and provide a tad bit of variety in the modulation. Where I really love inversion is with envelopes. A good old fashioned ADSR is wonderful thing. But sometimes, it’s just straight-up going the wrong way. What if I want the peak of the attack to be a valley. Bam, hit that sucker with an inverter and you have what you’re looking for.

By having access to these three, very basic, very fundamental functions, you have tremendous power over you control voltages, and thereby your sound. Blinds can do a lot more besides these, it’s a particularly wonderful mixer in my opinion. And while it’s a tad clumsy as a VCA it can and will get the job done. But whether or not you go for Blinds, you should strongly consider some module which will give you direct access to these three functions.

Attenuate. Offset. Invert. Get your control voltages under control!


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Honorable Mentions:
Mutable Instruments Blinds