I like it, but the best modules already have knobs and jacks for everything. When you have CV going into the jack, the knob acts as an attenuator or attenuverter. This means that the modules are generally larger. Make Noise generally does this and their modules are consistently bigger than everyone else, and they're also some of the most popular. Look at Maths. It's a slope generator and a mixer. It's fucking huge. But everyone has it because it's patch programmable. The problem in Eurorack is instead of making things patch programmable, they try to fit in a ton of functionality into a small space, so you have a lot of modules that have multiple modes where buttons and knobs all have different meanings depending on what "page" you're on. Fuck that. Almost every time I try a module like that, I end up selling it.
He's right about the interface being the point of Eurorack. Plugging things into other things is the whole point. When I have a module that has hidden state, I forget what state it's in or what the knobs mean. I end up avoiding those modules. With cables and knobs, I can see the state of the whole system. I need good cable management to make sure it's not spaghetti, but I already do that in code already, and it's not that different.
>It's a nice dream, of a synthesizer where any knob can be pulled out and replaced with a patch cable, and any jack can have a knob plugged into it to set it to a fixed value.
What's even better, though, is a coupled knob + jack where the knob turns into an attenuator for the input when a cable is plugged in, and works as a standalone knob otherwise. I think this is quite a common design.
I believe I've also seen patch cables with built-in attenuators.
Another common pattern is jack + offset. The most useful is when you have jack + offset + attenuator… but most modules pick one or the other for space reasons.
Totally. Also, an attenuator is easier and cheaper to implement, because it just requires normalizing V+ into the jack plug. An offset requires an adder.
My preference is: attenuator < offset < attenuator + offset. I see no benefit of having to remove the knob to get to the jack as proposed in the article.
Ok, but why stop here? You've effectively created a rotary potentiometer in one dimension, you could add two more dimensions like an analog thumbstick on a game controller. Do any controllers have a twistable thumbstick?
Also, like other commentors have stated - this could be a jack too, so you could have a jack knob analog stick.
BUT WHY STOP THERE?
You could mount it on a linear pot/slider.
BUT WHY STOP THERE?! (help me)
You could daisy chain pluggable rotary analog stick jack stacks...
There are several 'joystick' controller modules (Doepfer a-174-4 or Intellijel Planar come to mind) and the Doepfer also produces 3rd signal by twisting the knob.
It's interesting. I haven't been sucked into the Eurorack thing though — do people want not just patch cables all over their mixing desk but knobs as well?
Eurorack (and modular synths in general) seem like funny things. Like guitar pedals, I sense there are a lot of enthusiasts that do a lot more tinkering than actually playing them. Watching Rick Beato and guests on YouTube ... seems like a lot of musicians are looking instead for simplicity. Like a few good sounding pedals that, ideally, each have just a knob or two.
Maybe the synth-heads are in a whole different headspace though.
> It's interesting. I haven't been sucked into the Eurorack thing though — do people want not just patch cables all over their mixing desk but knobs as well?
I don't personally feel the need of wanting more cables all over my current setup, but sometimes I have had the feeling of "Oh if I could just modulate the VCF Cutoff on my Zen Delay with a patch cable from my modular instead of doing it manually" for some of the desktop units I have next to the modular.
And on the other side, I've also felt the need of having some of the patch holes replaced by knobs, so I could just twist and turn it to evaluate if I want to modulate it, instead of having to actually setup the patch. I could see something like this knob-idea being very useful for that, basically prototyping patches.
> I sense there are a lot of enthusiasts that do a lot more tinkering
This is definitely true, large parts of the community is about tinkering more than making music. But the same is true for programming, large parts of the community is not about problem solving, but coding. That's fine, we all have different motivations :)
What I found really useful (for myself at least) is to try to connect with people who are artists first, who just happen to be using modular synths, rather than finding people tinkering with modular synths who don't actually produce/perform music.
> I haven't been sucked into the Eurorack thing though
Good for you :) A friend pulled me into this dark abyss a month ago. Lots of fun, so many distractions, but lots of fun. Helps that Barcelona (where I live) have a lively community around modular synths as well. It is expensive though, and VCVRack doesn't come close to providing the same experience.
> Like a few good sounding pedals that, ideally, each have just a knob or two.
It makes for a nice narrative but I haven't found it holds much water; musicians are all over the place on this spectrum. You'll find both extremes very well represented, and a good chunk of people who compartmentalize their "dayjob" music and tinkering. I've found a lot of successful musicians love to tinker and are always on the search for new inspiration. Like any good craftsperson they take some amount of pride in their tools and I've been blown away by how technical many can get on the electronics side! It's always funny to see Reverb auctions go up for famous musicians and finding out a bassist in a pop punk band owns a bunch of weird synthesizers :)
Simple one to two knob pedals are a big deal but you'll see a very large number of pros touring with extremely complicated modeling setups and all sorts of gadgets. At a certain point you really know what you want, and having the ability to dial that in is important! I tend to gravitate towards simplicity in a band setting but I know a lot of people who want dirt pedals with 10 knobs so they can dial in the sounds they hear in their heads.
I swing bimodal on this. For a while I enjoy the most exotic modular patches and loaded pedalboard. Then for months I am all about piano and acoustic guitar, as vanilla as can be.
It’s all so deep I’m not going run out of fun in any mode.
Maybe they are tinkering, but sounds still come out while they are tinkering. So maybe they're playing music after all? The idea that if you're not recording and releasing tracks you're doing it "wrong" is a bit silly IMO. Just strumming a guitar or playing some chords on a piano without recording any of it was always an "acceptable" hobby and not considered "unmusical", playing with synths and sequencers is no different IMO.
A lot of the music is made just playing with different parts of the sound, and having all the controls exposed to be messed with can lead to more creativity.
IMO, kind of like how I enjoy Linux configuration files, in a way, more than I do a GUI that covers up 90% of the guts of an application or server software.
My favorite documentary I have not seen (yet), I Dream of Wires from 2013, about modular synthesizers. I know in some trailer there was a maker of modules saying something to the effect that if only people actually making music with their synths bought modules he would be out of business. Can't find that trailer now or I did not watch carefully enough now. There are a few different ones on youtube.
The knobs tend to be the "public API" and the patch cables the wiring up of the functionality to that public API. having a knob for each patch is akin to making every method 'public' instead of protected or private.
Don't get sucked into modular hardware synths. They are TONS of fun, but it is a very expensive hobby. Monotrail Tech Talk has a few excellent videos on YouTube, but he must have spent a fortune on his gear.
It's somewhat similar to people enjoying developing their game engine more than their game in my experience.
Provably why in attracted to it despite having little musical talent :)
> any jack can have a knob plugged into it to set it to a fixed value.
I'm kind of surprised he didn't start with a knob with a tiny accelerometer, mcu and battery in it to produce some sort of output signal into a stock plug depending on how the knob is oriented with respect to gravity.
I was wondering this - I'd buy this if I could just plug it into my existing sockets. I'm pretty sure you could get 50-100 hrs with a battery, but I wonder if you could have something that you wind-up like a mechanical watch.
It's an interesting idea (truly a clever way to accomplish this!), but I think it's addressing the symptom, not the problem. The symptom is that some jacks don't have associated knobs. The problem is that either the module designer or the module user is overly obsessed with miniaturization. The designer is at fault if it's a parameter that really should have had a knob with the jack and they avoided including one in order to keep things small. The user is at fault if they're trying to stay so space-constrained that they can't fit a module that outputs an DC voltage set by a knob into their case. There are numerous modules that do this (and often that attenuvert as well) and many of them are fairly small too.
Interesting idea for sure, but how is the feel of actually turning the knob? Seems to offer short to no resistance, which would make fast but precise movements pretty hard, something that is important for things like performances.
What would be a huge bonus point (but maybe unrealistic? I don't quite understand how the current implementation actually works) would be software-configurable resistance (physical, not electrical). I've spent a lot of time for my DIY modules to find the right knobs, or the right process to adjust the resistance of my existing knobs, being able to control that digitally could introduce a whole new level of fun.
My dream is a piano keyboard with entirely software controlled mechanical key response. Every key individually mounted on a servostepper. As a bonus it could be used as a fake player piano. Or for practice you could make the wrong keys hard to press. Endless possibilities.
A compromise that is affordable and does exist is programmable response curves to key velocity and aftertouch pressure. It can make sense to have different curves for eg. piano vs harpsichord even if you can’t change the mechanical key impedance.
I haven’t seen it in the wild, but using this you could make the wrong notes quieter/louder or even play a different sound. But I think we all know when we play a wrong note, so the utility might be small.
I'm not convinced it would work very well on making you a better player but who knows. Either way, it sounds like a good way to injure yourself. Piano is a very percussive instrument and if you're hitting the keys with any force and they don't give the way you expect them to I imagine that won't be very great for your joints.
That's so cool on so many levels, and I really enjoyed that indeed, now I have to fight the urge to try to build it myself, good thing it's weekend.
However, it does seem to miss the single most useful feature (for me) which is the resistance part. I understand there is a DC motor controlling the snap points and whatnot, but what I'd like is constant resistance I guess, to a configurable level, rather than snapping to specific points and such.
I don't think it would be possible to hack on top of the already made hardware, but didn't seem like it was already done in the software side of things, although I did skim through things so maybe I missed it.
Sounds reasonable, wonder how that would actually feel in real life? As far as I understand, this would pass through digital parts, adding a little bit of (maybe noticeable) latency, but I wonder if the latency gets high enough for it to be a bit jarring that the resistance is dynamically changing as you apply torque.
A differently complex and smaller approach might be to combine the knob with with an axial flux PCB-BLDC, like what Carl Bugeja made [0, 1]. It might be suited to get haptics in something as small as the article's knob, although to get an in-built display you'd have to use one of those displays that fit in lego bricks [2, 3] with a slip-ring.
Many thanks for the links/references. I don't really care about the display itself (probably prefer without it actually), but never saw those other links before, interesting stuff.
This looks super neat and probably a fun project to build.
> It's a nice dream, of a synthesizer where any knob can be pulled out and replaced with a patch cable, and any jack can have a knob plugged into it to set it to a fixed value. Whether it's actually practical to build a synth like this I'm unsure. It would probably only be worthwhile if you applied it to every single control on the modular, which rules out using other people's modules. You would have to invest heavily into the Eurorack Knob Idea. You couldn't even port other modules that easily, as many of them would expect a real potentiometer, whereas the encoder can only produce a voltage. Coupling it with a voltage-controlled potentiometer would work, but would be even more expensive.
Yeah, it's hard to imagine this fitting in nicely to everything since it's defintely more effort and work than just having a knob and a jack for the control of a particular thing. Esp. since most of the time, as a convention, you'll have a knob that controls the value, but when a jack is plugged in, this same knob acts as the attenuator for the signal.
I would have appreciated having an image or a pdf of the schematic for the design to understand it properly - i can get it from your github but I don't have kicad installed on this computer.
I'm esp. interested in the normalized behavior - ie. when you have a signal plugged in to the jack that is _not_ the potentiometer.. does it get passed through or does it have to go through this chip as well?
Having to supply a 3V to this to make it work as well is also an extra requirement of its usefulness in normal eurorack circuits - not a total dealbreaker but that does add extra requirements, and extra components to one's design.
"It's a beautiful dream – a very expensive, but beautiful dream."
While that might be true, what is expensive for me is chump change for someone else. However, that is very difficult to grok as there was no prices mentioned anywhere that I could see. Sure, it'll be expensive to me because I have to ask. But I also know that I cannot afford a fully spec'd out MacPro, but at least I can see the numbers.
1. I find Tim's work always so impressive and humbling. Compared to software, hardware projects seem infinitely more complex.
2. Speaking of knobs, I am writing a toy software synth for smartphones. Are there any design guidelines for mobile UI for audio? Knobs are hard to use and sliders take up a lot of space with only a little more precision. I experimented with curved sliders (inverted parabola or sine), but they are confusing since height doesn't really encode anything and the curvature is there only to make the slider longer. I didn't find any design systems focused on audio components.
Knobs shouldn't be hard to use - hold down the knob that needs the adjustment and then drag in either of two directions to set the value. Maybe have a pop-up over the knob that displays the value as it's in use.
Thanks! For me, this works well for knobs that don't require frequent adjustments. Currently, my knobs have little pills next to them that switch a knob to a "precision mode." It is a little quicker, but you may need to remember to disable this mode next time you use the knob.
I also played with the idea of letting users slide their finger off a knob (tap and slide away from the center). This allows for moving the finger over a longer circumference, hence enabling a great degree of precision. The problems with this approach are that it takes longer to operate such knobs, you need to communicate to the user what the max allowable distance from the knob is, it can interfere with scrolling, and it doesn't work for knobs close to the edge of the screen. (Your idea works well for knobs at the edges.)
And this is just knobs! There are many other components, interactions between them, as well as associated accessibility challenges, haptics, etc. Instead of reinventing the wheel, I was hoping that human factors people had developed relevant guidelines, but perhaps it simply is not a prevalent enough problem.
Loopy Pro has a cool convention that I haven't seen elsewhere for this. Drag up or down to change the knob value. While doing that, drag left or right to zoom in. That makes the up/down movement more precise.
I liked the video focused on his hands, where his gestures and expressing the rough size and orientation of things added to his verbal description. Not sure if this is a common technique, but works very well for this topic.
This is so cool and so clever I'm in awe, really. I'm grinning from ear to ear looking at this and jealous I didn't think of it. But the problem it solves is not quite one that anyone has. What does it offer over a built-in knob with a jack that overrides it beside compactness? A knob that's not designed for feel that you can misplace?
There's a miniature case study in thinking about innovation here. This is what the germ of a really neat idea looks like but you have to keep going and that's hard.
I'd be tempted to eliminate the patch cord altogether by using one of those pushbutton pots. Normally it would act like a traditional pot, but if you push it, it would go into a mode where you could choose from a variety of nearby inputs wirelessly.
The LEDs next to the pot would need to be an OLED display that indicates the selected input. Some form of extremely lightweight mesh network for control connections would need to exist, something with very low bandwidth and short range but also low latency. After 5 or 10 years' worth of tinkering, it might actually synthesize some sounds.
Right - it solves the compactness problem but introduces new ones. That said, from what I've seen of other people's modular setups, keeping them from growing without bound does not seem to be the highest priority in that world.
I'd also have to wonder how well a jack would hold up under regular use as a bushing. It's very common for engineers with little exposure to the connector industry (not my background either, but I read the data sheets and app notes) to underestimate how highly engineered and optimized for their use case even decades-old connector types are.
It would be nice to have something like the NKK display pushbuttons in the knob for a rotary encoder/pushbutton.
>After 5 or 10 years' worth of tinkering, it might actually synthesize some sounds.
Wouldn't it be more universally compatible to have a powered knob that outputs a adjustable constant control voltage? You'd probably want trim adjustments on it too.
Yes, there'd be an extra wire to the power supply module, but that seems fine for a modular.
Yes, but there are already many of these in modular form (usually attenuators normalled to +5V in the absence of input voltage or just fader modules without inputs). This is new :)
> Yes, there'd be an extra wire to the power supply module, but that seems fine for a modular.
Maybe other's modular synths look/work differently than mine, but when all the panels are installed, there is no way to pull a cable from underneath the panels/inside the case to the outside, without drilling new holes through some panel or the sides of the case. So not sure how you'd pull a cable from the power supply to the front side of a panel when it's closed like that. My case is a Intellijel Palette 104HP, maybe other cases expose the power supply to the outside?
As a fellow Eurorack circuit designer and university teacher on thst issue one immidiate issue I can see is one of practicality. Decent potentiometers are maybe a Euro per piece if bought in bulk, they have a start and an end which is nice and for analog gear you have direct control over the parameter, with very clear feedback what is going on — that is the main reason people want physical gear. So add in a LED ring for visual feedback and endstops.. Might be nice for a digital module.
But even then I'd wonder if it worth it, because of the high pcb space usage. With potentiometers as attenuators or attenuverters you can fit two pots next to each other in a space of 20mm which neatly aligns with the standard panel widths. Theoretically you could certainly get smaller with thst solution, but the hall effect IC needs to be accounted for as well. With existing pots I can use the space underneath. If your module is just 10mm wide that space is pretty premium..
I like it, but the best modules already have knobs and jacks for everything. When you have CV going into the jack, the knob acts as an attenuator or attenuverter. This means that the modules are generally larger. Make Noise generally does this and their modules are consistently bigger than everyone else, and they're also some of the most popular. Look at Maths. It's a slope generator and a mixer. It's fucking huge. But everyone has it because it's patch programmable. The problem in Eurorack is instead of making things patch programmable, they try to fit in a ton of functionality into a small space, so you have a lot of modules that have multiple modes where buttons and knobs all have different meanings depending on what "page" you're on. Fuck that. Almost every time I try a module like that, I end up selling it.
He's right about the interface being the point of Eurorack. Plugging things into other things is the whole point. When I have a module that has hidden state, I forget what state it's in or what the knobs mean. I end up avoiding those modules. With cables and knobs, I can see the state of the whole system. I need good cable management to make sure it's not spaghetti, but I already do that in code already, and it's not that different.
>It's a nice dream, of a synthesizer where any knob can be pulled out and replaced with a patch cable, and any jack can have a knob plugged into it to set it to a fixed value.
What's even better, though, is a coupled knob + jack where the knob turns into an attenuator for the input when a cable is plugged in, and works as a standalone knob otherwise. I think this is quite a common design.
I believe I've also seen patch cables with built-in attenuators.
the smartest pattern is used in mutable instruments beads, the "attenurandomizers"
it packs a ridiculous amount of functionality into a single plug & knob combo
Another common pattern is jack + offset. The most useful is when you have jack + offset + attenuator… but most modules pick one or the other for space reasons.
Totally. Also, an attenuator is easier and cheaper to implement, because it just requires normalizing V+ into the jack plug. An offset requires an adder.
My preference is: attenuator < offset < attenuator + offset. I see no benefit of having to remove the knob to get to the jack as proposed in the article.
The attenuator-inverter is super handy too. A gain knob that goes from -1 to +1 X.
Ok, but why stop here? You've effectively created a rotary potentiometer in one dimension, you could add two more dimensions like an analog thumbstick on a game controller. Do any controllers have a twistable thumbstick?
Also, like other commentors have stated - this could be a jack too, so you could have a jack knob analog stick.
BUT WHY STOP THERE?
You could mount it on a linear pot/slider.
BUT WHY STOP THERE?! (help me)
You could daisy chain pluggable rotary analog stick jack stacks...
----
The madness has taken him
There are several 'joystick' controller modules (Doepfer a-174-4 or Intellijel Planar come to mind) and the Doepfer also produces 3rd signal by twisting the knob.
It's interesting. I haven't been sucked into the Eurorack thing though — do people want not just patch cables all over their mixing desk but knobs as well?
Eurorack (and modular synths in general) seem like funny things. Like guitar pedals, I sense there are a lot of enthusiasts that do a lot more tinkering than actually playing them. Watching Rick Beato and guests on YouTube ... seems like a lot of musicians are looking instead for simplicity. Like a few good sounding pedals that, ideally, each have just a knob or two.
Maybe the synth-heads are in a whole different headspace though.
> It's interesting. I haven't been sucked into the Eurorack thing though — do people want not just patch cables all over their mixing desk but knobs as well?
I don't personally feel the need of wanting more cables all over my current setup, but sometimes I have had the feeling of "Oh if I could just modulate the VCF Cutoff on my Zen Delay with a patch cable from my modular instead of doing it manually" for some of the desktop units I have next to the modular.
And on the other side, I've also felt the need of having some of the patch holes replaced by knobs, so I could just twist and turn it to evaluate if I want to modulate it, instead of having to actually setup the patch. I could see something like this knob-idea being very useful for that, basically prototyping patches.
> I sense there are a lot of enthusiasts that do a lot more tinkering
This is definitely true, large parts of the community is about tinkering more than making music. But the same is true for programming, large parts of the community is not about problem solving, but coding. That's fine, we all have different motivations :)
What I found really useful (for myself at least) is to try to connect with people who are artists first, who just happen to be using modular synths, rather than finding people tinkering with modular synths who don't actually produce/perform music.
> I haven't been sucked into the Eurorack thing though
Good for you :) A friend pulled me into this dark abyss a month ago. Lots of fun, so many distractions, but lots of fun. Helps that Barcelona (where I live) have a lively community around modular synths as well. It is expensive though, and VCVRack doesn't come close to providing the same experience.
> Like a few good sounding pedals that, ideally, each have just a knob or two.
It makes for a nice narrative but I haven't found it holds much water; musicians are all over the place on this spectrum. You'll find both extremes very well represented, and a good chunk of people who compartmentalize their "dayjob" music and tinkering. I've found a lot of successful musicians love to tinker and are always on the search for new inspiration. Like any good craftsperson they take some amount of pride in their tools and I've been blown away by how technical many can get on the electronics side! It's always funny to see Reverb auctions go up for famous musicians and finding out a bassist in a pop punk band owns a bunch of weird synthesizers :)
Simple one to two knob pedals are a big deal but you'll see a very large number of pros touring with extremely complicated modeling setups and all sorts of gadgets. At a certain point you really know what you want, and having the ability to dial that in is important! I tend to gravitate towards simplicity in a band setting but I know a lot of people who want dirt pedals with 10 knobs so they can dial in the sounds they hear in their heads.
I swing bimodal on this. For a while I enjoy the most exotic modular patches and loaded pedalboard. Then for months I am all about piano and acoustic guitar, as vanilla as can be.
It’s all so deep I’m not going run out of fun in any mode.
100%, there's weeks I just plug straight into an amp because that feels right! At the end of the day it's great to have options.
Your pedal board/modular synth is a reflection of your personality.
Just like real life I have a tidy put together functional board, then a disturbing spaghetti mess tucked away in a corner that few are allowed to see
Maybe they are tinkering, but sounds still come out while they are tinkering. So maybe they're playing music after all? The idea that if you're not recording and releasing tracks you're doing it "wrong" is a bit silly IMO. Just strumming a guitar or playing some chords on a piano without recording any of it was always an "acceptable" hobby and not considered "unmusical", playing with synths and sequencers is no different IMO.
You're right. Someone's hobby could be "noodling" — with a guitar, synth, etc.
Watch some episodes of LOOK MUM NO COMPUTER for an example of the kind of tinkering/creativity some people at least love to have available in the physical realm: https://www.youtube.com/channel/UCafxR2HWJRmMfSdyZXvZMTw
A lot of the music is made just playing with different parts of the sound, and having all the controls exposed to be messed with can lead to more creativity.
IMO, kind of like how I enjoy Linux configuration files, in a way, more than I do a GUI that covers up 90% of the guts of an application or server software.
My favorite documentary I have not seen (yet), I Dream of Wires from 2013, about modular synthesizers. I know in some trailer there was a maker of modules saying something to the effect that if only people actually making music with their synths bought modules he would be out of business. Can't find that trailer now or I did not watch carefully enough now. There are a few different ones on youtube.
https://www.youtube.com/watch?v=rQSxqha62j0
The knobs tend to be the "public API" and the patch cables the wiring up of the functionality to that public API. having a knob for each patch is akin to making every method 'public' instead of protected or private.
Don't get sucked into modular hardware synths. They are TONS of fun, but it is a very expensive hobby. Monotrail Tech Talk has a few excellent videos on YouTube, but he must have spent a fortune on his gear.
It's somewhat similar to people enjoying developing their game engine more than their game in my experience. Provably why in attracted to it despite having little musical talent :)
I got sucked into it a little over a year ago, it's starting to wear a bit thin for me already though.
> I sense there are a lot of enthusiasts that do a lot more tinkering than actually playing them
It's called "sound design" :) Can't start on a song until the timbre of my never-quite-done-this-way-before saw tooth bass is juuuuuuust right.
> any jack can have a knob plugged into it to set it to a fixed value.
I'm kind of surprised he didn't start with a knob with a tiny accelerometer, mcu and battery in it to produce some sort of output signal into a stock plug depending on how the knob is oriented with respect to gravity.
Putting electronics inside the plug is nearly a mitxela trademark. https://mitxela.com/projects/flash_synth
I was wondering this - I'd buy this if I could just plug it into my existing sockets. I'm pretty sure you could get 50-100 hrs with a battery, but I wonder if you could have something that you wind-up like a mechanical watch.
Probably because pulling on cords can twist them. That’s what I thought when this occurred to me.
It's an interesting idea (truly a clever way to accomplish this!), but I think it's addressing the symptom, not the problem. The symptom is that some jacks don't have associated knobs. The problem is that either the module designer or the module user is overly obsessed with miniaturization. The designer is at fault if it's a parameter that really should have had a knob with the jack and they avoided including one in order to keep things small. The user is at fault if they're trying to stay so space-constrained that they can't fit a module that outputs an DC voltage set by a knob into their case. There are numerous modules that do this (and often that attenuvert as well) and many of them are fairly small too.
Interesting idea for sure, but how is the feel of actually turning the knob? Seems to offer short to no resistance, which would make fast but precise movements pretty hard, something that is important for things like performances.
What would be a huge bonus point (but maybe unrealistic? I don't quite understand how the current implementation actually works) would be software-configurable resistance (physical, not electrical). I've spent a lot of time for my DIY modules to find the right knobs, or the right process to adjust the resistance of my existing knobs, being able to control that digitally could introduce a whole new level of fun.
You might enjoy https://github.com/scottbez1/smartknob
The complexity of this approach (ignoring the display and flair) unfortunately means you won’t see this used too often due to cost.
My dream is a piano keyboard with entirely software controlled mechanical key response. Every key individually mounted on a servostepper. As a bonus it could be used as a fake player piano. Or for practice you could make the wrong keys hard to press. Endless possibilities.
Great idea and I’m shocked this doesn’t exist.
It would likely be very, very expensive.
A compromise that is affordable and does exist is programmable response curves to key velocity and aftertouch pressure. It can make sense to have different curves for eg. piano vs harpsichord even if you can’t change the mechanical key impedance.
I haven’t seen it in the wild, but using this you could make the wrong notes quieter/louder or even play a different sound. But I think we all know when we play a wrong note, so the utility might be small.
> Or for practice you could make the wrong keys hard to press.
This seems like a pretty cool idea
I'm not convinced it would work very well on making you a better player but who knows. Either way, it sounds like a good way to injure yourself. Piano is a very percussive instrument and if you're hitting the keys with any force and they don't give the way you expect them to I imagine that won't be very great for your joints.
That's so cool on so many levels, and I really enjoyed that indeed, now I have to fight the urge to try to build it myself, good thing it's weekend.
However, it does seem to miss the single most useful feature (for me) which is the resistance part. I understand there is a DC motor controlling the snap points and whatnot, but what I'd like is constant resistance I guess, to a configurable level, rather than snapping to specific points and such.
I don't think it would be possible to hack on top of the already made hardware, but didn't seem like it was already done in the software side of things, although I did skim through things so maybe I missed it.
Should be doable to add that. The BLDC needs to add a proportional (or any other function) force against the rotation direction until it reaches 0.
Sounds reasonable, wonder how that would actually feel in real life? As far as I understand, this would pass through digital parts, adding a little bit of (maybe noticeable) latency, but I wonder if the latency gets high enough for it to be a bit jarring that the resistance is dynamically changing as you apply torque.
This is all fairly normal in robotics, under a subset of (slightly overloaded naming sorry) “impedance control”
A differently complex and smaller approach might be to combine the knob with with an axial flux PCB-BLDC, like what Carl Bugeja made [0, 1]. It might be suited to get haptics in something as small as the article's knob, although to get an in-built display you'd have to use one of those displays that fit in lego bricks [2, 3] with a slip-ring.
0. https://microbots.io/products/motorcell
1. https://www.youtube.com/watch?v=CVszJMlvZcA
2. https://github.com/AncientJames/uGrey
3. https://www.youtube.com/watch?v=0pUV_3qeHog
Many thanks for the links/references. I don't really care about the display itself (probably prefer without it actually), but never saw those other links before, interesting stuff.
This looks super neat and probably a fun project to build.
> It's a nice dream, of a synthesizer where any knob can be pulled out and replaced with a patch cable, and any jack can have a knob plugged into it to set it to a fixed value. Whether it's actually practical to build a synth like this I'm unsure. It would probably only be worthwhile if you applied it to every single control on the modular, which rules out using other people's modules. You would have to invest heavily into the Eurorack Knob Idea. You couldn't even port other modules that easily, as many of them would expect a real potentiometer, whereas the encoder can only produce a voltage. Coupling it with a voltage-controlled potentiometer would work, but would be even more expensive.
Yeah, it's hard to imagine this fitting in nicely to everything since it's defintely more effort and work than just having a knob and a jack for the control of a particular thing. Esp. since most of the time, as a convention, you'll have a knob that controls the value, but when a jack is plugged in, this same knob acts as the attenuator for the signal.
I would have appreciated having an image or a pdf of the schematic for the design to understand it properly - i can get it from your github but I don't have kicad installed on this computer.
I'm esp. interested in the normalized behavior - ie. when you have a signal plugged in to the jack that is _not_ the potentiometer.. does it get passed through or does it have to go through this chip as well?
Having to supply a 3V to this to make it work as well is also an extra requirement of its usefulness in normal eurorack circuits - not a total dealbreaker but that does add extra requirements, and extra components to one's design.
Anyways... really cool idea :)
"It's a beautiful dream – a very expensive, but beautiful dream."
While that might be true, what is expensive for me is chump change for someone else. However, that is very difficult to grok as there was no prices mentioned anywhere that I could see. Sure, it'll be expensive to me because I have to ask. But I also know that I cannot afford a fully spec'd out MacPro, but at least I can see the numbers.
1. I find Tim's work always so impressive and humbling. Compared to software, hardware projects seem infinitely more complex.
2. Speaking of knobs, I am writing a toy software synth for smartphones. Are there any design guidelines for mobile UI for audio? Knobs are hard to use and sliders take up a lot of space with only a little more precision. I experimented with curved sliders (inverted parabola or sine), but they are confusing since height doesn't really encode anything and the curvature is there only to make the slider longer. I didn't find any design systems focused on audio components.
Knobs shouldn't be hard to use - hold down the knob that needs the adjustment and then drag in either of two directions to set the value. Maybe have a pop-up over the knob that displays the value as it's in use.
Thanks! For me, this works well for knobs that don't require frequent adjustments. Currently, my knobs have little pills next to them that switch a knob to a "precision mode." It is a little quicker, but you may need to remember to disable this mode next time you use the knob.
I also played with the idea of letting users slide their finger off a knob (tap and slide away from the center). This allows for moving the finger over a longer circumference, hence enabling a great degree of precision. The problems with this approach are that it takes longer to operate such knobs, you need to communicate to the user what the max allowable distance from the knob is, it can interfere with scrolling, and it doesn't work for knobs close to the edge of the screen. (Your idea works well for knobs at the edges.)
And this is just knobs! There are many other components, interactions between them, as well as associated accessibility challenges, haptics, etc. Instead of reinventing the wheel, I was hoping that human factors people had developed relevant guidelines, but perhaps it simply is not a prevalent enough problem.
Loopy Pro has a cool convention that I haven't seen elsewhere for this. Drag up or down to change the knob value. While doing that, drag left or right to zoom in. That makes the up/down movement more precise.
I liked the video focused on his hands, where his gestures and expressing the rough size and orientation of things added to his verbal description. Not sure if this is a common technique, but works very well for this topic.
This Old Tony (a hobby machinist / welder on youtube) has made all of his videos in that format. It works very well!
https://www.youtube.com/c/thisoldtony/videos
This is so cool and so clever I'm in awe, really. I'm grinning from ear to ear looking at this and jealous I didn't think of it. But the problem it solves is not quite one that anyone has. What does it offer over a built-in knob with a jack that overrides it beside compactness? A knob that's not designed for feel that you can misplace?
There's a miniature case study in thinking about innovation here. This is what the germ of a really neat idea looks like but you have to keep going and that's hard.
As he mentions in the video, the whole motivation is compactness. When your panel looks like https://learningmodular.com/the-eurorack-expansion-project/ , every mm^2 matters.
I'd be tempted to eliminate the patch cord altogether by using one of those pushbutton pots. Normally it would act like a traditional pot, but if you push it, it would go into a mode where you could choose from a variety of nearby inputs wirelessly.
The LEDs next to the pot would need to be an OLED display that indicates the selected input. Some form of extremely lightweight mesh network for control connections would need to exist, something with very low bandwidth and short range but also low latency. After 5 or 10 years' worth of tinkering, it might actually synthesize some sounds.
Right - it solves the compactness problem but introduces new ones. That said, from what I've seen of other people's modular setups, keeping them from growing without bound does not seem to be the highest priority in that world.
I'd also have to wonder how well a jack would hold up under regular use as a bushing. It's very common for engineers with little exposure to the connector industry (not my background either, but I read the data sheets and app notes) to underestimate how highly engineered and optimized for their use case even decades-old connector types are.
It would be nice to have something like the NKK display pushbuttons in the knob for a rotary encoder/pushbutton.
>After 5 or 10 years' worth of tinkering, it might actually synthesize some sounds.
Yeah.
Wouldn't it be more universally compatible to have a powered knob that outputs a adjustable constant control voltage? You'd probably want trim adjustments on it too.
Yes, there'd be an extra wire to the power supply module, but that seems fine for a modular.
Yes, but there are already many of these in modular form (usually attenuators normalled to +5V in the absence of input voltage or just fader modules without inputs). This is new :)
> Yes, there'd be an extra wire to the power supply module, but that seems fine for a modular.
Maybe other's modular synths look/work differently than mine, but when all the panels are installed, there is no way to pull a cable from underneath the panels/inside the case to the outside, without drilling new holes through some panel or the sides of the case. So not sure how you'd pull a cable from the power supply to the front side of a panel when it's closed like that. My case is a Intellijel Palette 104HP, maybe other cases expose the power supply to the outside?
Anyone know what is being used to render the git repo for this? https://git.mitxela.com/euroknob
looks like it's this: https://git.mitxela.com/web-git-sum
Fantastic idea except for the proprietary 3.5" knob. From the video it appears the magnet is required to discern position.
As a fellow Eurorack circuit designer and university teacher on thst issue one immidiate issue I can see is one of practicality. Decent potentiometers are maybe a Euro per piece if bought in bulk, they have a start and an end which is nice and for analog gear you have direct control over the parameter, with very clear feedback what is going on — that is the main reason people want physical gear. So add in a LED ring for visual feedback and endstops.. Might be nice for a digital module.
But even then I'd wonder if it worth it, because of the high pcb space usage. With potentiometers as attenuators or attenuverters you can fit two pots next to each other in a space of 20mm which neatly aligns with the standard panel widths. Theoretically you could certainly get smaller with thst solution, but the hall effect IC needs to be accounted for as well. With existing pots I can use the space underneath. If your module is just 10mm wide that space is pretty premium..
I’m just waiting for the Eurorack Boombox revolution to hit.
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