Two jittery, unstable sequencers in one patch: Marco is a “random walk” generator, Polo tries to catch up with it.
This is a ZEBU patch focussed heavily on making fun, generative CV signals for a modular synth, but it does also make some nice sounds on its own. On the left is a “random walk” mechanism (Marco) where a CV value increases in steps until it randomly decides to flip direction and starts decreasing. It’ll keep walking up and down forever. The chance that it flips direction can be set high (so it’ll flip a lot and mostly hover around the 0-centre), or low (so it’ll go all the way up or down before it turns around).
On the right is a second CV value (Polo) that chases after the first and tries to catch up to it.
Both of these generate a quantized pitch signal, but there’s some additional CV flavouring by adding jitter to the clock (from ‘humanizing’ to absolutely mangling it) and instability to the pitch (reminiscent of the Make Noise Wogglebug) and I added 2 sawtooth voices that can sound pretty nice. The step size for both Marco and Polo can be varied (and randomized) independently, and there are two ‘chase modes’ which strongly affect the interplay between Marco and Polo and leads to some interesting, generative sequencer behaviour! Marco…? Polo!
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[OVERVIEW]
-Input/Output: Stereo input (goes only through the reverb), Stereo out
-CPU load: Around 95%
-Build: Initial version built with firmware 2.70
-MIDI: Controls are NOT YET set to CCs (I normally use channels 21/36, see CONTROLS section for details).
-CV Inputs:
1) Marco Step Size
2) Polo Step Size
3) Range In
4) External Clock In (if using this, toggle the EXT CLOCK button next to LFO to ON)
-CV Outputs:
1) Marco Pitch (1V/oct, can be tuned on the IO page)
2) Marco Env
3) Polo Pitch (1V/oct, can be tuned on the IO page))
4) Polo Env
[REVISIONS]
1.1: CV in/outputs added.
1.0: Initial patch.
[CONTROLS]
All controls on PAGE0 (see below for a “Picture Manual” in the comments). The Stereo Output module with gain parameter, the Plate Reverb module, and Pitch CV output tuning controls are found on the IO page.
Controls for both Marco and Polo:
STEP SIZE (how much the pitch jumps up/down per step)
VELOCITY (set to 0 to silence internal voice)
RND STEP SIZE (toggles randomization of step sizes; still takes SETP SIZE into account)
ATTACK/DECAY (speaks for itself)
FLIP CHANCE (sets the chance that Marco changes direction up/down) Only for Polo (on the right)
Overall controls (in the middle):
LFO (sets internal clock speed)
TOGGLE EXT CLOCK (toggle ON when using external CV clock)
JITTER (adds random delay to each clock tick)
RANGE (sets the spread of pitch CV)
SLEW (sets the slew time; interacts with a lot with INSTABILITY)
INSTABILITY (sets amount of pitch wobble; at high levels it really overshoots the goal, fun)
CHASE MODE (toggles between both Marco and Polo moving together, or moving one or the other; both modes are affected by the M.P. BIAS value)
ZOIA stompswitches = unused
ZEBU buttons = unused
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[PATCH STRUCTURE]
This patch might have very limited use cases, but I don’t care, it was a fun one to build.
‘Marco’ is basically a S&H connected back into itself, and at each clock tick it is incremented or decremented (?) by a small amount, which makes it a crude sequencer. The direction is changed with a probability gate (aka Bernoulli-gate), but the trick here was to make sure the probability increases to 1 before it reaches the upper or lower limit. That way, the FLIP CHANCE value still affects things, but even when that’s at 0 it’ll always flip when it reaches the limit and keep going back and forth forever.
‘Polo’ was a whole different build; it’s also a S&H abused as a sequencer, but it calculates the difference between itself and the last Marco value and tries to close that gap. Depending on the STEP SIZE settings for both, it can either catch up instantly, or always lag behind and creep up in small steps.
There are two ways in which Marco and Polo are triggered; in the first mode (CHASE MODE button off) both sides can trigger at the same time, with a probability bias set by the M.P. BIAS value. In the CHASE MODE (button on) only one side at a time will trigger; depending on the M.P. BIAS setting the Polo sequence will keep triggering till it’s (mostly) caught up with Marco, which will then jump away suddenly.
Then there is the JITTER of the clock, which is simply a CV Delay after the master LFO and a Random module into the CV Delay time. And SLEW and INSTABILITY are weird; there is a Slew Limiter module and a CV Delay module set up so that as the CV Delay time is increased it doesn’t ‘know’ it has already reached its target value, so it’ll start to overshoot. At higher INSTABILITY settings there’s a strange sort of vibrato, but as SLEW is also increased the pitch will really overshoot its target and jiggle around for a bit before settling back down. It reminded me a bit of the Make Noise Wogglebug. A bit more controllable I guess (which is a good thing?).
This patch was first intended to just ‘create interesting CV’ but there was CPU room for 2 synths as well, so I made some simple sawtooth voices, added quantizers. Suddenly it was surprisingly capable of nice sounding ambiences. The interaction between the left and right sides (especially the timing between triggers) is quite interesting and musical and with different STEP SIZE, FLIP CHANCE, CHASE MODE, and M.P. BIAS settings it makes a great generative sequencer!
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[TIPS/TRICKS]
>>> Start with low JITTER, INSTABILITY and SLEW and just play around with the specific step controls and see how the behaviour of both sides changes.
>>> The internal synths are a bit simple but play around with attack and decay settings and chuck them into a big reverb and you’ve got a great ambient patch. Make it weirder with increased INSTABILITY and SLEW.
>>> This is a great source of CV for a bigger generative patch.
[THOUGHTS/IDEAS/PLANS]
This patch is done, no future plans.
If there’s any bugs/questions/remarks/requests or suggestions for improvement, please let me know!
Enjoy!
(Image: Alberto Seveso)
Picture manual:
Attachment Manual-Marco-Polo-63c67fae34cbc.jpg