Understanding noise in Mod slots

[Insert Values]

Hi, everyone .

It's been for some months that I am quite focused on prophet rev 2 and learning how it works in deep and some synthesis. However, there are subtle tricks and techniques that I am still trying to understand to have as a resource in future patches.

Today I would like to ask about the mod slots, and if someone can give me an explanation to try to understand better how it works, specifically with noise. I do have some patches, where a mod slot source is a noise itself, usually, they give a small amount(no matter negative or positive) like 2,3,4 or 5 as the amount, and the destination is the cutoff. This is giving a subtle dusty sound that can be pretty cool. Especially when it's quite subtle it gives a bit of the feeling of a tape.

Here's my question: What really happens when you put noise to the cutoff? or even just to any other param itself? I clearly can hear the result, but I cannot draw a picture in my head on what's going on. With the cutoff param as a destination, I can say that when the filter is completely opened, the noise is gone. You can really appreciate this "dust" movement especially when the filter is quite closed as 4 pole at around 60/70 value. Is the noise closing the filter, instead of the filter itself? I cannot visualize what happens and what's the relation between these two. As well I tried a super dramatic 127 value into an osc 1 freq, and I do see the classic up and down on tone( with a fixed frequency) along with the dusty sound as well.

Thanks in advance 

[Autosynther]

I think it works like this
- noise is modulating the cutoff frequency, meaning moving the cutoff very fast
- this in contrast to raising the noise knob and sending noise to filter that will filter it
- listening to it, it is much lower frequency than if the actuall noise would vary filter cutoff
- so most likely it's up to processor internally to sample noise as fast as it can and change cutoff
- thereby sounding like a sample and hold, kind of
- so where ever filter cutoff is according to envelope, it is overlayed with this noise modulating it, creating a jagged edge of cutoff at hi speed

Cool idea, thanks for posting it. This way you get a sample&hold to use on any parameter, but no frequency control as on LFO's. On LFO section it is called Random.