# CV input responds to -/+5v

Hello again

I’m going through different algorithms in my disting and learning about full/half-wave rectifiers and using Nebulae as the module to send CV too.

I’m going through the manual of Nebulae and seeing that the “CV input responds to +/- 5V, and is added to the knob position.” and I’m having a hard time understanding how that works when the knob isn’t at 12 o’clock. I’m not really sure how to word this, but would the knob at 12 o’clock be the equivalent to 0v or 2.5v? if the knob is completely clockwise, would any additional positive cv be clipped? Or does the CV input virtually move the knob to a position that would allow it to have 5v added/subtracted?

Hey, that’s a tricky question, I also thought about. About 0 or 2.5 Volts at 12 o’clock, my wild guess would be 2.5 since a range of 5 Volt overall seems to be quite the standard for most CV-modulation-inputs, aside from Pitch-CV for example.

If you then add a positive value like + 2 Volts, you’d go up to 4.5 volts on the new internal value. If you add -2 Volts, to 2.5, you’d get to around +0,5 volts. I think the +/-5 Volts applies to “you can move back to 0 Volts from 5 volts or you can move from 0 Volts to 5 Volts max”

Do you posess of a Make Noise Maths or something similiar that has the ability to send offsets over 5 volts? - If so, I’d choose a CV-Input that changes the sound considerably. Maybe not the Windowsize, you better go and pick size or density with moderate Overlap-settings dialed in. If it has a threshold at 5 volts and you max an external source to over 5 volts, you should experience that nothing changes after a certain rotation. - In fact, I will go and test it

Edit followup: I tested it with a manual Offset of my Maths Ch. 2 (+/- 10 Volts) and Ch. 3 (+/- 5 Volts) - and the result was, that Ch. 3 tweaking from the Nebulae’s value set to the middle position changed for the whole rotation, but with Ch. 2 it stopped changing the value quite early before even half the rotation has been done… - I then set the target-knob to fully counterclockwise and did the process again - here the changes of the sound also did happen until the Maths Knob was completely turned at Ch. 3 and did appear to stop at the Ch. 2 early. → Considering this, the Values of Nebulae would start at 0 Volt, middle of the way at 2.5 volt until end of the way at 5 Volt.

But I’m sure it would be easier if one of the makers just told you

2 Likes

I actually did this test before posting. I have overlap completely counter-clockwise and then modulated the density with ochd. It’s a triangle wave though, so maybe a sine would be better to test with? It was a little hard to tell based on hearing the grains (sort of like particles into almost white noise). I also put it through the rectifier on Disting and there was a noticeable difference in the positive vs the negative cycles of the amount of grains I’d hear.

Maybe I should record a scale and try it with the start knob…

–edit–
spelling and a rephrase

Edit followup: I tested

Thank you for doing this. Little better than my test and it makes sense. There isn’t a specific reason I want to know this other than a neurotic curiosity because I couldn’t explain it to myself. But also, it’s nice to know everything about a module in my rack, so that’s what these sessions are for

In most cases, I’d probably use an envelop anyway with potentiometers like this.

← and that’s exactly why I tried it

2 Likes

This is correct! Basically, any CV sent to the parameter input will offset the parameter by the amount of voltage sent to the CV input, with hard caps at 0V (fully CCW on the knob) and +5V (fully CW on the knob).

So, if you were at the middle position on the knob (+2.5V) and sent +4V to the input, the parameter would max out at the +5V position, or fully CW on the knob. If the voltage inputted was instead -4V, then the parameter would hit the minimum of 0V, or fully CCW on the knob.

Let me know if this makes sense! I’m currently working on an updated version of the Nebulae manual, in the style of the Nautilus, Aurora, and new Data Bender manuals, so I can include a section explaining voltage offset if that helps!

3 Likes

It does make sense, thank you! And i think explaining it in the manual would be very helpful

2 Likes