Who is all geeked out on analog logic?

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Who is all geeked out on analog logic?

Post by Dolphinwolf » Mon Nov 16, 2020 12:08 pm

I am geeked out on analog logic. Sending audio through analog logic circuits that resemble simple digital ones. What information sources are there for this type of thing?

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Re: Who is all geeked out on analog logic?

Post by dragulasbruder » Mon Nov 23, 2020 7:32 pm

I'm only becoming familiar with analog logic this year, honestly being more familiar with Boolean logic made it difficult to understand until I thought about running binary 0-5V signals through it and then understood how "max" is analog OR and "min" is analog AND.

Analog logic is great for audio-rate stuff but it also really shines for AM at control rates. Great for drones. I haven't seen much literature about it, but audio-rate max functions (Serge Peak/Trough) have figured in as a nonlinear shaper neuron component in the excellent Synthese Humaine youtube tutorials.
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Re: Who is all geeked out on analog logic?

Post by Bachelard » Mon Nov 23, 2020 11:08 pm

Here! Love my min/max/sum/diff stuff. I don't have too much technical knowledge about it but generally like the idea of anything that can derive additional signals from simple existing ones.

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Re: Who is all geeked out on analog logic?

Post by KSS » Wed Nov 25, 2020 10:45 pm

Bachelard wrote:
Mon Nov 23, 2020 11:08 pm
Here! Love my min/max/sum/diff stuff. I don't have too much technical knowledge about it but generally like the idea of anything that can derive additional signals from simple existing ones.
Add comparators to your arsenal. They are excellent for doing what you wrote. And Mixers. VC Mixers too<--AKA VCAs.

Adding levels to digital* inputs and selecting from digital* outputs based on levels<--use mixers to create levels, or VCAs- brings a new dimension to the basics.

Plain logic is like 2D chess vs comparators and mixing giving you Spock's** 3D version.

*Many of the 'analog' logic modules you buy have a fixed input level and a fixed output level. The leaves them closer to digital than analog in actual result.
** The StarTrekTOS character, not the IJ module.

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Re: Who is all geeked out on analog logic?

Post by Bachelard » Thu Nov 26, 2020 12:13 am

KSS wrote:
Wed Nov 25, 2020 10:45 pm
Bachelard wrote:
Mon Nov 23, 2020 11:08 pm
Here! Love my min/max/sum/diff stuff. I don't have too much technical knowledge about it but generally like the idea of anything that can derive additional signals from simple existing ones.
Add comparators to your arsenal. They are excellent for doing what you wrote. And Mixers. VC Mixers too<--AKA VCAs.

Adding levels to digital* inputs and selecting from digital* outputs based on levels<--use mixers to create levels, or VCAs- brings a new dimension to the basics.

Plain logic is like 2D chess vs comparators and mixing giving you Spock's** 3D version.

*Many of the 'analog' logic modules you buy have a fixed input level and a fixed output level. The leaves them closer to digital than analog in actual result.
** The StarTrekTOS character, not the IJ module.
This is definitely my kind of discussion thread :)
VCAs, definitely. I actually ordered a small Doepfer Quad VCA and their dual polarizer (more VCA) on top of having Blinds and 6 other vcas in my relatively small system.

And I have a Compare 2 and an obscure Circuit Abbey Impulse Drive comparator/PWM thing that are both pretty magical.

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Re: Who is all geeked out on analog logic?

Post by Snufflepuff » Sun Dec 20, 2020 12:35 pm

This sounds intriguing. If all I know now is OR/AND functions, and that a comparator sends an output once a threshold is crossed, is there a resource to kinda sorta get me up to speed? Thanks!

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Re: Who is all geeked out on analog logic?

Post by Bachelard » Sun Dec 27, 2020 10:42 pm

Snufflepuff wrote:
Sun Dec 20, 2020 12:35 pm
This sounds intriguing. If all I know now is OR/AND functions, and that a comparator sends an output once a threshold is crossed, is there a resource to kinda sorta get me up to speed? Thanks!
Check out Mystic Circuits ANA and Erica Synths Pico A Logic. the Mystic Circuits page in particular describes the ANA module pretty well. In essence, analog logic works with variable signals (like continuous slopes/curves and not just square waves or generate on/off signals).
https://www.mysticcircuits.com/product/ana
https://www.ericasynths.lv/shop/discont ... co-Alogic/

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Re: Who is all geeked out on analog logic?

Post by Grumble » Mon Dec 28, 2020 5:03 am


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Re: Who is all geeked out on analog logic?

Post by Dcramer » Sun Jan 03, 2021 12:36 pm

:party: This is also my kinda thread!

Sadly, because ‘I am the dumb’ :hmm: it takes me way longer to understand what you guys are talking about :oops:

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Re: Who is all geeked out on analog logic?

Post by soon_come » Sun Jan 03, 2021 12:39 pm

One of my favorite things to do is use a passive diode or (for example, PulpLogic) for things other than gates because its output is an analog or (minus a bit of voltage drop). I mostly use the resulting signal for modulation, but you can do this with standard waveforms to get interesting textures too.

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Re: Who is all geeked out on analog logic?

Post by KSS » Sun Jan 03, 2021 11:04 pm

^ Yes. I keep trying to promote diode patchcords. So simple. So many uses.

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Re: Who is all geeked out on analog logic?

Post by exper » Sun Jan 03, 2021 11:13 pm

Honestly, this is the stuff that makes modular synth patching the most fun IMO. CV processing with analog logic and gate/trigger processing with boolean logic/flipflops, etc.
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Re: Who is all geeked out on analog logic?

Post by PhineasFreak » Mon Jan 04, 2021 1:45 am

to begin with a slight digression,

not only do i own a set of RYO 4hp logics [made using transistor-resistor technology - it got man to the moon, its good enough for our music!] - surprise surprise i helped conceptualise the idea, design the circuits, do prototyping etc lol, i also own a full set of all the ladik 4hp boolean logics and math functions available - and also i have two klavis logica xt's;

but,
when i procured all those 4-5hp neat little digital logic modules i also, with no planned out purpose or need or them, i grabbed the ladik comparator, min-max, median, derivator, and very importantly a coupla doepfer beauties - the quad envelope follower and the slope grenerator. many know the value of the slope generator in such areas as analogue logic since its the precursor to maths - it basically is half a maths/DUSG/whatever - envelope followers and slews are great at converting digital info like clocks/gates/trigs into analogue cv or even audio.
[n.b. when thinking audio rate, filters come into play - you want to smooth an audio rate digital signal - i.e. a square wave? an lpf is your guy, an audio rate slew basically - applying such things can slim data from a clock or cv running at adio rate into a string of trigs that are more sparse or a varying but gently undulating analogue cv]

my favourite of these neat little quirks i had yet to discover when buying them was ladiks median - a function associated with the min-max but less commonly seen and so not as well understood in its possibilities - especially ladiks, because it can be used in a number of ways:
- As a middle value selector: the best known use for most median modules, following middle voltage value of 3 inpuits.
- As a median value selector using only two or even just one cv: since the module has two fixed cv sources - ladiks has an offset derived from the two unused knobs and when no external cv is connected, then one knob sets the limit and the other knob can output a voltage between 0V and limit - allowing you to derive a median output from just one input voltage and the other knob setting or 0V!
- As a voltage limiter: an input voltage will only be passed as long as its between hte two limits - whether set by the the knob offsets, ground or an external applied offset limit.

tbh i tend to enjoy most the truly weird ones like a good ol' fashioned comparator or ladiks derivator that take analougue inputs and yet produce digital outputs - things that allow you to convert 'wavefollowed' audio signals or fluctuating smooth/slewed cv's into gates, trigs, clocks and other on/off digital, squared outs.

eitherway, the world of analogue logic is not just fun but the also the weirder world of interchanging between analogue and digital to get mixed up systems involving both being processed in the same way - even more fun!

i think ive mentioned before in a post somewhere on this forum my theory that you can think of all modules as tools for converting one signal type into another:

Code: Select all

Setups like mine relly show this, the basic building blocks of synthesis only fall into a few categories
- comparators [cv into trig/gate], sequencers/env followers/syncable lfos [trig into cv], quantisers [cv into 1v/oct],
multiple output logics/math/vc clock divs etc [trig to multiple dif trig patterns],
logic combiners/mixers [turning multiple trigs/gates/cvs into single complex trigs/gates/cvs]
vco’s [1v/oct cv into audio],
filters/waveshapers/audio modulators [basic audio into complex audio/varying audio], etc. ...
...you just need to start [with] somthing like ...
an lfo to generate a raw signal from scratch, and then via converting that signal into more complex varying cv’s
[ - clocks, 1v/oct, melody/bassline/chord patterns, drum rhythms, modulation signals],
audio, [and many other] outputs, and generally [therefore]
more diverse signals, the only thing missing from the whole ... is feedback loops
my entire world is generative sequencing right now - so its very convenient to think 'i have an lfo generating the raw source cv's - i want a 1v/oct phrase that slowly evolves over a very long time but has some feeling of familiarity to it although not repeating' - solution, convert the raw cv, a pattern - mix multiple waveforms from lfo [mixer is analogue _or_ combiner], turn new waveform into 1v/oct [quantiser], output needs to feedback to input so as to influence the phrase to slowly evolve [mult the output 1v/oct to the source lfo rate cv in, via a median or wavefolder module to limit te excessive runaway increase in speed of the lfo that would occur if 1v/oct pitch were direct link feedback to lfo rate];

- already that setup has a consistent source of repeating familiarity: the source lfo's output pattern
- it will slowly vary via changing the source lfo via feedback, but not too much or too fast: limiting median/wavefolder rectifying peaks
- lack of variation can be fixed by using two cross modulating / cross syncing lfos as source [vc clock div great for sync feedback loops]
- extra feedback loops can create variance without deviating completely and permanently from the original pattern, using, e.g. conversions from analogue to digital or vice versa to account for 1v/oct to sync clocks or squarewave outs to gentler fall rise signals using slews or env followers...

such an approach ensures you always have the right tool for the job and can get any cv, clock, gate, trig, audio or 1v/octv as necessary from any available source regardless of its native state - try applying this theory, it'll revolutionise yor patching technique!

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Re: Who is all geeked out on analog logic?

Post by BWBKc6VyUr » Fri Jan 08, 2021 8:17 am

PhineasFreak wrote:
Mon Jan 04, 2021 1:45 am
i want a 1v/oct phrase that slowly evolves over a very long time but has some feeling of familiarity to it although not repeating' - solution, convert the raw cv, a pattern - mix multiple waveforms from lfo [mixer is analogue _or_ combiner], turn new waveform into 1v/oct [quantiser], output needs to feedback to input so as to influence the phrase to slowly evolve [mult the output 1v/oct to the source lfo rate cv in, via a median or wavefolder module to limit te excessive runaway increase in speed of the lfo that would occur if 1v/oct pitch were direct link feedback to lfo rate];
This sounds like exactly the kind of stuff I'm trying to do right now, but I don't quite understand the technique. Could you explain it again in more detail?
Last edited by BWBKc6VyUr on Mon Jan 11, 2021 5:07 am, edited 1 time in total.
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Re: Who is all geeked out on analog logic?

Post by PhineasFreak » Mon Jan 11, 2021 12:52 am

BWBKc6VyUr wrote:
Fri Jan 08, 2021 8:17 am
PhineasFreak wrote:
Mon Jan 04, 2021 1:45 am
i want a 1v/oct phrase that slowly evolves over a very long time ...
This sounds like exactly the kind of stuff I'm trying to do right now, but I don't quite understand the technique. Could you explain again it in more detail?
i want a 1v/oct phrase that slowly evolves over a very long time but has some feeling of familiarity to it although not repeating' - solution,:

- convert the raw cv, a pattern - mix multiple waveforms from lfo [mixer is analogue _or_ combiner],
take a couple [minimum two] LFO's and combine some outputs in a mixer to make a complex waveform [e.g. some ramp, sine, saw, and tri in different amplitudes and frequencies]
[cross modulating the rate or sync of the two or more LFO's will make for even more complex patterns that vary every other or every 4 or whatever phrases.]
when the output of this mixer is fed into a quantiser it will give a nice melody phrase to work with
[note, this will be a continuous stream of pitch changing output from quantiser so we will also need to derive a gate pattern for rhythm]

- turn new waveform into 1v/oct [quantiser],
just feed the output of the mixer the was fed the LFO's into the quantiser's input.
[if you feed the square wave into a quantiser that takes trig ins (may need gate to trig converter) you can get some even more rhythmic changes in pitch, and likewise a quaniser that produces gate outs or trig outs will give you your rhythm for your voice modules.
alternately, sending the square outs of the lfos into boolean logic modules you can get rhythmical gates to drive the voice modules]


- output needs to feedback to input so as to influence the phrase to slowly evolve [mult the output 1v/oct to the source lfo rate cv in...,
the output of the quantiser (1v/oct signal) needs to influence the modules generating its output - i.e. we need to create a feedback loop involving the LFO's driving the quantiser pitch, then the quantiser pitch out [i.e. the 1v/oct signal] going back to LFO rate in, so as to create an effect that each time the LFO's change the quantiser pitch it changes the output of the LFO's feeding into it so that it doesn't repeat identically.
[this gives us our evolution - each time the quantiser outputs it changes the LFO's creating its input via feedback loops so the pattern iss never quite the same even tho similar]
so, we mult the 1v/oct out of the quantiser [the out would normally just drive pittch in of the voice modules] and the multed copy[ies] go to rate inputs of the LFO's generating the patterns for the quantiser [attenuated/attenuverted/offset as necessary]

- ...via a median or wavefolder module to limit any excessive runaway increase in speed of the lfo that would occur if 1v/oct pitch were direct link feedback to lfo rate]; or total lock up,
we need to include a module that takes away the peaks and troughs [or limits] the signal from the quantisers 1v/oct out so that when it feedsback into the LFO(s) rate input it doesnt cause a runaway loop getting faster and faster, pitch increasing, making for rate increase, causing pitch increase, causing lfo rate increase etc. or alternatively drop in pitch, slowing lfo so causing drop in pitch so slowing lfo til the whole thing locks up dead.

as you might note, utilities are crucial as in any moduilar patch - you will need mixers, attenuators, inverters, offsets etc.

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Re: Who is all geeked out on analog logic?

Post by BWBKc6VyUr » Mon Jan 11, 2021 9:08 am

Thanks PhineasFreak it makes more sense. It involves a few types of modules I don't have yet (Quantiser, S&H). But it's helpful in so far as it helps me define my next purchases to expand the generative dimension in my patches.
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Re: Who is all geeked out on analog logic?

Post by PhineasFreak » Mon Jan 11, 2021 2:41 pm

BWBKc6VyUr wrote:
Mon Jan 11, 2021 9:08 am
Thanks PhineasFreak it makes more sense. It involves a few types of modules I don't have yet (Quantiser, S&H). But it's helpful in so far as it helps me define my next purchases to expand the generative dimension in my patches.
i highly recommend digging deep into the generative thread that has been chugging on for many tens of pages - so much valuable info and great ideas!

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Re: Who is all geeked out on analog logic?

Post by KSS » Tue Jan 12, 2021 5:22 am

:agree:

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Re: Who is all geeked out on analog logic?

Post by modeleus » Wed Jan 13, 2021 11:38 am

Muting with Envelopes
I personally like to use a trick for MAXin Gates with an envelope and the MAX result goes to a percussion module. The result obtained allows me to mute the percussion when the envelope is triggered, for example muting the kick while the pitch of the oscillator is softly detuned.

I´m taking advantage of the necessity for a LOW stage prior to a HIGH one in the trigger/gate input of a percussion module (envelope, etc) for it to respond. If the module has already triggered once and the signal going to the input is still above 0V the module won´t respond again until it drops down.

When the envelope is not triggered the MAX out is equal to the Gate signal in one of its inputs so the percussion is working as normal. When the envelope is triggered the result of the MAX will be a combination of the square pulses and the envelope but the lower voltage won´t be 0V so the percussion is shut down.

This technique is also a bit more subtle as you cut the trigger signal instead of the sound.

Controlling Craziness
I love to obtain crazy gates related to the CVs happening in the patch but sometimes the Comparator/Logic Chain can get messy. To let it flow but keeping the vibe as well I like to MAX/OR my main sequence with the result of a MIN/AND between the logic gates and a gate signal coming from a second sequencer. If the Gate out of the second sequencer is LOW the logic gates will be shut off. Once a Gate happens in the second seq the result of the MIN is equal to the logic and it is combined with the main sequence.

LOGIC & 2SEQ -->MIN & Main seq --->MAX ---> out

With that technique you can have your basic rhythm and spice it up at your wish with the logic signals happening in other modules.
Try it with two sequencers, one double the speed, and use the slow one to define logic bursts at the end of each 2 bars.
With this trick the PW of the Gate from the 2 Sequencer controls the lenght of the "logic burst" so you can try and modulate that parameter to evolve the fills during the performance.

I hope is all clear, let me know if you use it!

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Re: Who is all geeked out on analog logic?

Post by EATyourGUITAR » Tue Jan 19, 2021 12:06 pm

I petition the masses to stop using the terminology analog AND/OR. instead I propose the well understood seldom conflated terminology of MIN/MAX. SUM and DIFF can be described as a mixer and a mixer with an inverting opamp on one of the inputs.

inverting gain stage is the math of f(x)=-x
a mixer is f(x,y)=x+y
diff is f(x,y)=x-y

min can be described as
IF x<y THEN x ELSE y
max is the opposite of min
IF x>y THEN x else y

this is why it is possible to use a comparator for <
you can use a VC crossfader to handle the IF THEN ELSE

all you get from a min max module is a consolidated VC mute with an analog comparator.

I will remind people that all logic modules used in analog modular synthesis are in fact analog comparators in front of digital logic modules. there are an infinite number of voltage states being used as input to any digital logic module used in modular. to be precise, digital logic circuits only operate on 2 state inputs that are discrete. because the digital logic modules must interface user systems, the digital logic is not exposed, it is protected sitting behind level shifters, reverse voltage protection, over voltage protection, low pass filtering etc..
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