MATRIXSYNTH: New Cogito Cartesian Sequencer for Audulus

Wednesday, January 28, 2015

New Cogito Cartesian Sequencer for Audulus

"Using Audulus for audio processing and pushing the iPhone to its ultimate limit, Audulus user Bimini Road has created Cogito, a Cartesian Sequencer. Building on the work of other talented Audulus users--JDRaoul, afta8, and jjthrash, --- the patch is worked out and explained in detail on the Audulus Forum.

The Cogito Sequener’s user interface is enabled by the Custom Nodes upgrade, an Audulus feature which allows custom-designed user interfaces.

Audulus is a minimalist modular software synthesizer and effects processor. With Audulus, users can build synthesizers, design new sounds, or process audio. All with low latency real-time processing suitable for live performance.

Audulus for iOS is available on the App Store for $14.99. An iPhone 4s or iPad 2 is required.

Audulus for Mac is available on the Mac App Store for $29.99. Mid 2010 or later Mac is required.

Audulus for Windows is available directly through for $29.99. Buy now and receive ALL in-app upgrades FREE. That’s $45 worth of upgrades.

For more information, visit"

The following are some details on the sequencer captured from the Audulus forum. Impressive.

"Ok, so here it is - the first (somewhat buggy) draft of Cogito, my Cartesian Sequencer - so called because...well, you'll see. I pushed the iPhone to its absolute limit with this one. It only takes up - ONLY, haha - 30% of the CPU, but I can *barely* get it to work with a synth beefier than 1 OSC node, 1 ADSR, 1 delay, and 1 reverb. It's official - I need to get a new Mac if I really want to pursue my Audulus dreams.

First, thanks are in order:

@JDRaoul - for as-yet-unimplemented help and the LCD number hack
@afta8 - Scale mapper - (w/ 1 modification - knob instead of fixed root note - try it out!!! Sounds AMAZING especially if you modulate it just a teensy bit around a value)
@jjthrash - more help that hasn't made it in yet

Known issue: the number 7 (and 17) doesn't display correctly. Probably gummed something up while pasting it in. All other numbers display correctly.

Features (Top to bottom, left to right)
LCD Numeral Display - displays the value of the step at the intersection of the XY coordinates.
Top 2 LED lanes - displays the maximum step value for the X sequencer
3rd LED lane from top - current X sequencer step
Bottom 2 LED lanes (above XY plane) - displays the cursor location on the X axis
LED XY field (the mostly filled-in part in the picture above) - 8 stacked 16 step sequences. Sequence 1 = Y1, Sequence 2 = Y2, etc.
2 LED lanes in from the left - displays the maximum step for the Y sequencer (Y only has 8 steps, so anything over 8 wraps around - cool bouncing effect if you set it to 12 or so)
Next LED lane in - current Y sequencer step
% Button - toggles the % knob on and off
Blank button - writes the V knob value to whichever coordinate the cursor is hovering over (0=skip)
V - "voltage," or, a number between 0-24 which then gets multiplied and shunted through @afta8's scale mapper
X - controls X cursor position
Y - controls Y cursor position
O - if X sequencer is NOT running, O will control which sequence is playing
R - root note of scale mapper - must be set to an integer to be in tune with anything on this planet, but very cool if modulated (may even build in a lil' LFO for just that purpose)
= Button - Syncs X and Y sequencer (reset)
^ Button - Start/stop Y sequencer
^ Knob - Y sequencer speed
Left # - X sequence max step
Right # - Y sequence max step
% - divides/multiplies the X sequence step number which in turn drives the MUX that controls the Y sequencer. .5 = half as fast (it's done with a multiply node). Cool stuff can happen with this knob. Only works when the Y sequencer is running.
Output hole - internal keyboard output (very useful if connected to Y and O simultaneously)
Lighted button, bottom left - Toggles keyboard control on/off - keyboard currently only works from C4-C5 (all white keys) - will fix this in the first full version
> Button - Start/stop X sequencer
> Knob - X sequencer speed
2nd lighted knob - Write random function - whatever Y lane you have selected, it will write random values based to each step. Very useful to quickly get up and running, or just to seek songwriting inspiration. Because the scalemapper is there, everything will sound in-key. You could potentially master this function and make improv sequenced synth music (at least, that's what I plan to try to do!). Push to write - wait a brief moment, then turn it off again (if you have it on while you scroll through other steps, it will write a random value to the new lane's 16th step because of the way the one-shot works - not necessarily a bad thing, just make sure you turn the button off if you don't want that to happen - I accidentally did this at 1:06 of the sound sample above)
<> Knob - Dividing function - shrinks the range of the random numbers
+ Knob - Raises the floor for the random numbers. To get zeros (skips) more often make this knob go negative.
X Gate - X pulse
Y Gate - Y pulse

To get an idea of why I spent so many hours working on this thing, listen to the above demo - this is a recording of my first time actually playing with Cogito. The picture from above shows what it looked like while I was playing with it. I turned on the keyboard control, wired the output hole to the Y knob and the O knob, clicked C4, pushed the write random, pushed the button again to turn it off, clicked D4, repeated, etc, until the whole grid was full. Now, I can play each of the 8 sequences with the keys C4-C5. What I'm doing throughout the demo is changing the clamping values and writing new random numbers.

To get a hang of how this works, set the <> function to 6-8 so that the steps being written hover closely together. Set the + knob to zero for the first step. Write the sequence to Y1. Repeat on Y2, Y3, etc, but increase the + knob each time - what you'll end up with is a kind of pseudo arpeggiator with more uniqueness to each step.

Another way to use the sequencer (without a keyboard) is to set X and Y speed equal, press sync, and now the values will be read from 1*1, 2*2, ... ,7*7, 8*8, 9*1, 9*2, ... , 16*7, 16*8. Try toggling the Y sequencer on and off to switch between the "diagonal" sequencer to the "straight" or normal sequencer. This is the function that really puts the "Cartesian" in Cartesian Sequencer.

To make this a 128 step sequencer, you have to set the Y speed 1/16th of the X speed and press the = button. IMPORTANT: Get as many decimals in there as you can - if the proportion is not a rational number, they will eventually drift apart (which will still probably sound cool, but won't work exactly like a 128 step sequencer).

Please, please, please - if you read this far, it means you're as excited by this beast as I am. If you enjoy it, leave some feedback on how you use it (or better yet, record a ditty with it!) and don't hold back on the critiques. Also, just wonder at the guts (will be more organized in full release) - there are probably 1000+ connections. This sequencer is a true testament to how well @Taylor designed the UI for the iPhone. Also, a conductive stylus really helps. (EDIT: And Netflix. Lots and lots of Netflix. Just started Dexter and I'm loving it!)"

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