“Analog logic” tricks?

So for a drum track I could set up a Euclidean rhythm. I. could even set up two of them.

But is there a way I could take two Euclidean streams and derive AND OR XAND XOR and/or a flip flop?

It would be cool for generating more complex rhythms.

Yes, I’m going to be annoying and try to figure out how to translate various Eurorack tricks to Hapax.

and most wont work … esp. the more generative stuff we do with eurorack :wink:

Im not even sure I know of a eurorack sequencer that allows you to that… without using another (so external) module … which you could of course also do with Hapax.

actually, thats not quite true…
Ive just written a new sequencer and logic module for the percussa ssp, so I actually can do precisely this.

but back to your point, Im not really sure how this would look on a sequencer (like the Hapax)…as it basically means running two sequencing streams (which is what a Euclid is) and combining, I guess you could do this with MATH across tracks … (like NEI on Elektron) - but that often feels like a waste of tracks.

… and I cannot see it being popular enough to write an entirely new ‘track type’ for.

but who knows…

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I don’t think there is. In Euro I’d take two streams and run them through a logic module. But I sort of think of the MIDI effects like modules. Today I piled up a bunch on a single track. Some things work: I could run two Euclidean sequences and modulate them with LFOs. Less luck (musically) when trying to arpeggiate them.

I totally think a logic MIDI effect is doable since channels are already polyphonic. I might try to draw one up. I realize it would not be a hugely popular request.

At some point I’ll give up and integrate some of my Euro with my Hapax. I just want to learn it really well first.

I dont think midi fx are really that similar to modules … since they are a linear flow of signals. were something like a logic module in eurorack is N signals into 1…
as I said that more similar to having N track going into 1…

I just don’t see how it can be done without being a huge ‘kludge’…

but hey, doesnt matter what I (or anyone here) thinks, its down to if Squarp devs like the idea or not…
if you can come up with an idea that makes it an elegant solution that has broad appeal, send it into Squarp via the contact form and perhaps they will go for it.

I think it depends on whether there exists a facility for mixing or separating MIDI signals inside the MIDI standard, and the Hapax OS.

This weekend I spent some time trying to blend Euclidean streams, modulate them with LFOs, etc., and some combos worked. Others didn’t; I’m still figuring it out. I know MIDI is more linear, and I’ve just spent a bunch of time having my brain blown up in terms of non-linear approaches to sequencing.

Would absolutely love to see logic implemented on Hapax. Could definitely see it living within the MIDI effects. Pam’s New Workout could be good inspiration for how to implement this - each channel of PNW allows you select what kind of logic and which channel it’s derived from.

Correct me if I’m wrong, but having Logic as a MIDI effect would also mean being able to apply logic to external MIDI/CV sequences as well.

Adding NEI tracks to the Math section could work too (or why not both!), but I think it might be more flexible as a MIDI effect, especially if you wanted to combine logic with Math.


Awesome. Let’s figure this out a little more so we can make the same feature request. You’re right that we don’t even need to mix MIDI channels or streams. A plug-in could just “listen” to another channel and the derive logical conditions for notes.

So parameters would be something like

Source track 1
Source track 2
Source track 3
Operation: and, or, xand, xor, ff (else?)
Destination: note event ( like Euclidean?) or can we be more creative?


Definitely something along the lines of this. That would be great to derive from multiple track sources. To do this on PNW, you have to “cascade” the logic, which itself isn’t so bad, but it would certainly make it easier to just have more than one option there.

I’m not quite sure what Destination would be in this case - would you mind explaining further? In my mind, the logic would just be determining if a step would play or not - similar to Chance, except based on logic as opposed to a percentage. Since it would be a MIDI effect, it could be combined with the Euclid, Chance, Arp, Randomizer, etc.

Happy to align on the feature request. I think a good amount of people would be interested in something like this, even if people don’t know it yet. Could be a good learning tool as well.

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I agree.

For destination it could be a single pitched note, or all notes at that time in the sequence. It could even be routed to other tracks. Could also be used for probability of automation.

ah, if you’re willing to give up multiple tracks for this I can kind see this being possible.
(I mentioned this in previous posts above)

I also think that if its a midi fx, then it would/should work on any ‘note stream’

(also perhaps another way to consider this is to forget notes … and think of automation lanes and using FX with these, in many ways automation is more similar to CV than notes!?)

questions then raise about polyphony though…
e.g. does an AND only work if its the same note? or any note?

if you are translating eurorack ideas, we have to move from what is essentially a monophonic signal world to a polyphonic one…

I think articulating some (musical) use-cases would be a good way to get to a better understand of whats required…


a) drum track logic
I could see it being useful within a single drum track, to be able to have logic applied
tom gate = kick xor hihat.
tom2 gate = not hihit
this becomes most useful (aka not static) when used with things like change/maths

the complication here is… this likely needs some kind of time unit for the check…
i.e. we probably want trigs rather than gates… but for some tests that implies a kind of ‘sampling’ time.

b) melodic track
perhaps play a BASS note on T3, if a note is present on chord track (T2) AND lead track (T1)
I can feel this as a possibility , but mechanics of how this works rather eludes me.

e.g. which notes are we talking about? should T3 notes be derived from T2?
again when does it play? is it a trig? is it a gate ?

… this is kind of ‘fudged’ a bit in eurorack, as often the target module decides if to interpret as a trig or gate i.e. the leading edge of a gate is a trig!.

whats interesting about articulating use-cases, is we can even see above, the different between wanting logic between notes (use case a) vs across tracks (note dependent or not?)

also if we mix in FX , then we need to also consider processing order of tracks…
if you say you want to use logic on T4 ,that is derived from a Euclid FX on T1 and T3 ,
then T1/T3 must be fully processed before T4 can be calculated.
something easy to say ‘of course’ too… but could easily be a source of ‘assumptions’ that are really difficult to explain to (some) users.

eurorack does not have this , since all processing is (essentially) continuous… rather than ordered.
even in virtual modular, e.g. vcvrack, this is done at audio rate, and we use ‘signal graphs’ to ensure as much as possible (e.g. excluding feedback signals) they are processed in an optimised order.

overall, I can definitely see it being fun incorporating things like logic … and more generally some of the more generative approaches (e.g. separating notes and gates/hocketing).
I think it’d be good to think of how that applies to streams of discrete notes (or automation) as opposed to cv, which I think has an inherently different nature.

hopefully that way we’d get something that fits how hapax works, and so can be implemented.

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Thanks @technobear . I don’t actually think we need to give up tracks to do this though of course I don’t know the backend of the Hapax.

For musical use cases, almost all of the ones I have in mind are rhythm. Let’s take two:

  1. A drum sound. Derive snare, hi-hat from interaction of the kick and a melody line on another track. The plugin listens to the kick drum and the melody track on another track and compares. Whenever a note sounds, on either, it does the comparison. It can then output a midi event that’s a specific note with specific velocity and duration (eg, snare, hi-hat). Do this three times and you’ve got a logic-based drum part.

  2. Whether a specific note sounds. The plugin compares input from two tracks in the Hapax, and does the comparison any time either of them sounds a note, outputting the logic functions to a specific note with a specific velocity and duration (say, C#4, 16th note, velocity 100). This could be part of a polyphonic line where an additional note appears or does not. With multiple logic plugins on a single track you could derive a whole melody / chord structure from other things playing. This is sort of like how Euclidean works right now, but with logic instead.

  3. Whether a specific step of a polyphonic sequence sounds. The plugin compares input from two tracks in the Hapax, and does the comparison any time either of them sounds a note, outputting the logic functions to a note on or note off message as the sequence plays that overrides the note on/off of the programmed sequence. So you can choose to hear your programmed sequence or NOT hear your programmed sequence according to a specific logic function.

The parameters for note logic:

Knob: parameter
1: input 1
2: input 2
3: Logic function (and/or/xand/xor/nand/FF, whatever else we can think of)
4: Note
5: velocity

The parameters for step logic:

Knob: parameter
1: input 1 (takes note on and off info from another track or from one of the drum tracks if it’s on a drum track)
2: input 2 (takes note on and off info from another track or from one of the drum tracks if it’s on a drum track)
3: Logic function (and/or/xand/xor/nand/FF, whatever else we can think of)
4: step on or step off

Again, I’m not a MIDI expert, so please tell me if this won’t work for some reason.

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What jes Is describing Is something similar to how aux events/intertrack operations work on the cirklon and It would be very cool. Altough on cirklon aux events affect note values (and a bunch of other things) other than steps on/off
That’s basically what makes the Cirklon, well…the Cirklon :grin:.
No need to waste a track for It, It could be a conditional trig but based on events from other tracks. Like:

If the snare hits, add an octave to track 1 50% of the time.

If hapax Is already one of the best sequencer in the market… with a feature like this It would be unrivaled and contrarily to Technobear I think that a lot of people would be interested.


Thanks everyone! Unless anyone has any more suggestions, I’ll submit a feature request with the description in my last post and a link to the thread.