Using frequency multipliers to create noise

[sean]

Starting this thread here, so it is easier to refer back to later (and this info doesn’t just get lost in the abyss of Discord).

First, here is this excellent tutorial by @Marizu on creating white noise using Stairs:

White Noise Tutorial using LZX Stairs 2025

[sean]

And then, since I don’t have a Stairs — but I do have Staircase and VU002 — I tried to generate similar results using those. Tried both Cadet Hard Key and Polar Fringe as keyer (examples directly below use PF).

Here are some results (at 1080p30):

Not able to quite get pure/dot noise, always some amount of line/slew look to it. As @rempesm pointed out: “Part of it is that Expedition modules like Staircase and Polar Fringe use 499R series outputs instead of 75R outputs so you’re going to get at least some obviously slewed output on hard edges in HD timings.”

Here is the patch for the above, single channel tests:

Also tried running the same noise texture through 3x Hard Key, each with a channel of an RGB signal modulating it, and ended up with this:

Here is the patch for the RGB test:

[sean]

And then here are a couple examples using Polar Fringe for the red channel and Hard Keys for the blue and green:

Here’s the patch for these:

[reverselandfill]

Thanks for this thread, it is very informative!

As for the availability of SNOW:
I have the new prototype of SNOW2 on my bench, and it is looking pretty good.
things to do: adjust footprint for SOP8 lm6172, finetune the frequencies for the 4 different outputs

Sneak preview:

[sean]

Realized I had a Gen 3 Keyer at hand, Ribbons, so tried with that. Definitely a little different flavor, harder, with less of a goopy/slewed look to the noise/image output. And more variation over image to noise ratio with the center and span controls. Plus, you can do colorization effects with its three outputs (I also sorta assume Ribbons is breaking down some of the slew-y gray trails from VU002 into smaller parts, since that is what it does…?).

Here is the pure noise from Ribbons:

Some with image added, showing some variations in image to noise ratios (dependent upon knob settings of Center, Center CV, and Span):

Mono patch:

(Pure noise patch didn’t include image input into Center CV. And I found either the image or the noise could go into the main or Center CV inputs and interesting results could be had with various knob settings.)

Also tried some colorization, using multiple outputs. Didn’t quite get this dialed in very well, but hopefully this gives some idea:

(With Span at minimum, you get b&w)

RGB patch:

And just one more, with the image going into the input and the noise into Center CV, for a more “classic” Ribbons/Castle ADC colorization look, with just a little noise added in (you can get more interesting/less “rainbow” color palettes by switching around which output goes to R, G, and B, and especially if one puts a matrix mixer after it, FWIW):

[Boneoh]

Thanks for posting this. I like the colorized one the best! It’s motivating me to experiment.

[Marizu]

I’ve managed to simplify @sean 's Staircase version of the patch down to Staircase, a keyer and a fixed 1.25.volt source.

Adding things like the Syntonie VU002 into the feedback loop will definitely change the nature of the noise but as I don’t currently have that or Solaire, I couldn’t really experiment with it.

White noise Tutorial using LZX StairCASE 2025

[fairplay]

…thank you all for the inspiration and especially for bringing this (back) here to the forums so users not using Discord can participate…

[sean]

Yeah, Discord is good for back and forth patter or spitballin’ but TERRIBLE for documenting/archiving info and techniques.

[sean]

Tested out Marizu’s settings for using just a Staircase to create noise and want to confirm I found the results roughly analogous to what I was doing with a VU002 in the loop, both at NTSC timing and 1080p30, using Ribbons as my keyer in the patch. Which is to say, yeah, doesn’t look like the VU002 is necessary.

NTSC:

1080p30:

Also, took the video input out of the equation and just played around with using Ribbons’s three outputs to create colored noise, by adjusting the Center and Span controls:

Ribbons does seem to break down the noise into finer segments as one goes down the less significant bit outputs (as I would expect). This is D0, D1, and D2 at full Span setting and the same Center setting for each (roughly in middle):

D0:

D1:

D2:

[sean]

Also found that, if I put a Curtain in the feedback loop, I could switch from noise to a pattern by flipping the Shape switch:

Most interesting to me perhaps (since I often work with pulled stills), in that it sometimes created some sorta interested glitches during the transitions: