Hi,
after playing around with the Axcore, I've made the decision to build a case/cabinet around it. I want my own standalone Synthesizer.
You can see the current state here, if you like. Also a Sound example.
Axcore Experimental Synthesizer
Best Mario from Synth-Project
nice, Mario!
do you planned to share your beautiful patch when done?
I'm looking for such a thing like this, less technical and more musical, as reference 
the controller looks awesome too...
really cool stuff.
have you considered running it as a multi core system?
all your projects looks great, where do you source all the parts from (keybeds, faceplates etc) ?
Id be really interested to hear how you go about building a synth like this, and how tricky it is...
looking forward to see how this progresses
The patch you see on my site is only the sub patch. The mono version. I loaded it into the main patch to play it 3 voice polyphonic. There are also the effects. I want to try, to optimize the patch, because it needs about 94% of Core Ram usage if i play polyphonic.
The sub patch has a midi mapping for one of my controllers. So i don't need to have all the parameters "On parent".
The main patch has only a few, not all. To control all parameters with the mouse on the PC, i could give you the monophonic sub patch as a normal patch if you want.
Best Mario
Thank you very much.
Knobs and pots are from:
Midi Equipment are from Doepfer:
For the moment i make every day changes on the front panel. But i think, end of januar i could finished the synthesizer and make a youtube video.
Best Mario
It really looks great (like all your stuff).
I was wondering, are all your controls going into the axoloti via the Doepfer board ? Does it not limit you to 128 values for each controller (7 bit)?
Since using axoloti's 10 bit (1024 values) gpio's, I have a problem going back to the old midi standard again.
Anyway, great to see you on the axoloti wagon, and well done for all your great projects
i am certainly interested in this idea.
i have two questions though:
how many axoloti pcb's do you plan to use for this project, becasue i see alot of knobs, requiring more than 2 axoloti core pcb's.
and if this is going to be sold as a kit, what would the price tag be?
Sorry I was wrong and not clear.
I mainly wanted to say that once you've tasted the luxury of using 12 bit controllers (nice smooth filter sweeps...) it not very fun trying to do it in 8bit (and sometimes sounds awful)
Hi,
at first, to control over 100 parameters i use two Doepfer midi interfaces.
And yes it's right, the Doepfer interfaces only support 7 bit.
The big question in every community, is it enough or not. I feel similar when everyone say not for the filter cutoff frequency.
But how many vst instruments or iOS apps really supports 14 bit for all parameters.
Back to the Axcore. All of the Oscillators have a tune and fine tune parameter divided by 8 and 64 or 128. For me, that is smooth enough to detune the oscillators with 7bit. Also the Speed of the LFO.
For the filter cutoff parameter I could use the Axoloti inputs, but not for all.
On the other side let's talk about the analog inputs. A standard potentiometer has a angle movement of about 300 degrees to control a voltage. I have this range to control 7bit that means cc values from 0 to 127. What happens if I would control 14 bit with this pot. Is it then smoother or would I need high precision potentiometer or an encoder ? And how much cost it if I need about 100 of these pots. I don't know.
At the end the Axcore Synthesizer will cost me about 1000€ as a 7 bit version. It's more than enough.
About the multicore. Nice idea. For the moment I use about 94% of the core ram. I must think about to optimize the patch or with multicore I could use on core only for the effects for example. But how to handle it as one synthesizer if I want save presets,if I can do that one day.
But hey it's only a hobby. The goal is that all works at the end. How good or bad we will see. I'm not a professional musician.
Best
Mario
Hi Mario, thanks I would very interested to study your patch for my axoloty practice
I think that the community will be pleased if you post the monophonic subpatch.
Thanks for your kind reply and keep us informed about your interesting hardware project.
(I still have to uderstand how to connect knobs to axoloti...)
very few soft (or hard) synths support 14 bit anything (ok, except PB 
) ... I keep an eye for this, as the Eigenharp supports it.
you don't hear stepping, as they all then smooth the values out.... this is of course also possible in axoloti.
i also added 14 bit midi support to Axoloti a while back... so i thinks in the latest release.
(midi/in /cc hr etc)
o.k, then i have a question. For example you use a sawtooth oscillator. This oscillator has one parameter, the frequency.
The range of this parameter is from -64 to +64. That means from C-1 to G#9. So you can choose every Note with a 7Bit resolution.
What happens if i use a 14Bit resolution ? I think, i get frequency between each notes. If i want to emulate a Synthesizer like the EMS VC3, then i need this higher resolution, because it sounds terrible if i hear steps in the frequency.
But if i wanna build a Synthesizer like Minimoog or MS-20, i don't need that. I need an octave selector and a Detune Knob. All is possible with 7Bit.
What i wanna say is, it always depends on what you wanna build. It makes no sense to build all with 14Bit, if you don't need it.
For me, 7 bit is enough to have fun with a self-made Synthesizer. This is an Experimental Synthesizer. For the Filter Cutoff, for example, i could test to use a separate Ctrl/Dial B with a divider, to control the pitch input of the multimode Filter, maybe i have a smoother control of the Cutoff Frequency. And that is it, why the Axoloti makes so much fun.
Edit: in my sound example on my page, you hear how the 7Bit resolution works. For the Filter Cutoff i goes from the Value +64 to +20, and then i use the Bandpass Parameter from 0 to +50 to get the choir like sound. For me its smooth enough. I can´t hear any steps with my old ears. Lol.
Best
Mario
the parameters are all 32 bit floats.
the only 7bit mapping (outside of the midi/in objects) is for parameter mapping, which personally I would avoid if your building a dedicated controller.
hard to describe what Id do, but basically keep the user interface (in broadest sense) separate from the sound generation components, then things like octave selectors/detune vs continuous frequency are merely a 'skin' on the engine/patch.
As @mtyas notes, the feel of a pot/fader scanned out at 3kHz/12bit is so much better than any midi controller, when controlling the pitch of an oscillator or filter.
14 bit midi, well even pitch wheels in by far most keyboard controllers only effectively use only 7 bit, while a standard pitch bend midi message has 14 bit resolution. At higher than 7 bit resolution, the risk of an accidental message transmit becomes significant, users will not like to see an event without cause when working with a DAW.
I agree with @SynthProject too, if you play keyboard with a knob panel, many controls do not benefit from over 7 bit, like envelopes or LFO stuff.
If you play knobs, controlling intense oscillator modulations etc, 3kHz/12bit is really nice. Even with cheap ordinary pots, not VCS3-style multi-turn pots, the tiniest movement of your fingers translates into sound.
hmm...
I do agree > 7 bit is not required for the majority of controls, probably only those which are used for direct performance, i.e. at your finger tips, hence why things like the Eigenharp support it. Even then most modern synths will smooth out controls for 7 bit, so its hardly noticeable.
but midi as a protocol (ignore transport for a moment), 14 bit midi vs a different 12 bit encoding is not going to as such feel worst/better, assuming the quality of components used are the same), and given a reasonable implementation no more likely to have 'accidental' transmission.
but there are many poor implementations of midi that introduce jitter, especially at 14 bit, often not helped by the USB or DIN 'transport' and the way PC handle it... (widely reported)
hopefully axoloti does not have this issue, since its running on an RTOS, and processes at a high priority.
pitchbend, sure on your 'average' keyboard, when doing a bend over a couple of semitones, 7 bit might be enough... but this is not the case when you start using with other controllers where the bend range is much larger, e.g. expressive controllers, theremins, midi guitars. e.g. the Haken Continuum for its full size has a 96 semitone slide, at 14 bit this is not enough resolution, so they use 21 bit. (an extra CC to supplement).
a bit of trivia, the Continuum uses midi internally between its keybed and sound engine (Eagen Matrix) and my (limited) experience with it and other musicians reports, is it 'butter' smooth
your 3khz is extremely high, the developers of the expressive controllers have obviously been very interested at what scan rates the musicians can feel..... most of them have settled on between 500-1000hZ and Ive not seen any complaints. though I will grant the Eigenharp has the highest at 2kHz and this is often reported as feeling the most 'alive' (but this likely due to many factors, given its unique design and software)
that all said, of course if you buy a midi controller of the shelf, its unlikely they will tell you what the scan rates are, so using your own pots/axoloti you bring this into your own control might feel better than many commercial controllers.
Yes thats all right....
Anyway... the Axcore is finished. Thanks a lot for this great Development !
All the best and keep on your good work.
Mario
wow, id love to see a video.... Im in awe of this project (and other work you have done)
a few specific questions... I'm trying to figure out the steps needed to do this..., perhaps you could pint me in the direction if I'm missing/misunderstanding something.
a) Keyboard
so your using a doepfer keyboard + controller boards...
so I guess there keyboards which seems to be a fatar + the MKE?
(Im thinking perhaps a desktop module, might be more suitable for me, but still interested how its done... oh, and building a case for a desktop module i think is easier... its just a box )
b) knobs/switches
so the knobs/switches come from Musikding.de , then those connected to a USB64 from doepfer
http://www.doepfer.de/usb64.htm
you needed 2 since you have > 64 controls.
I guess you need internally a midi router, to combine the inputs from the 2 USB 64, and the MKE
connecting, USB64 (I've check the manual)
ok, so I see its has 8 banks LP1-8 with 10 connectors,
8 appear to be the input value... and then 2 connects for GND/+5v
you just connector the 8 pots to these GND/+5v and 1-8 ? (and then they are powered from the USB64)
switches seem similar, but you need a 10k resistor , and can only go on inputs 1-16?
(so this implies you have 64 pots or 48 pots + 16 switches?)
its seems the electronic skills required are limited? pins on one end to the board (I guess a GND/+5v rails as needs to go to multiple ports) , the solder directly to pots, and for switches you need to solder the 10k resistor in line.
(I can imagine cable management is fun, with so many pots and switches )
c) case
hand built case i guess, and with a front panel front panel , laser cut for you? and then a skin made to the same dimension by someone like
d) power...
I guess the MKE / USB64 all need a separate power supply, of have you combined them...
can it be powered from USB? ... Im thinking an internal USB hub to provide power (to the USB64 and Axoloti) and a single point of access. (I'm assuming if the hub is powered that should be plenty to drive the pots + usb64 + axoloti..
is this broadly correct.... its alot of work, but I'm trying to figure out if I have the skills to do it...
(I've not alot of electronics experience, but think i could solder wires to pots_
anyway, fantastic work... as I said, i see your website and just think 'wow!'
Hi, wow many questions. Ok.
a) yep. It's a 4 octave keys from Fatar with a modified MKE Electronic.
b) all midi units from Doepfer has midi in and out so I can route midi through each units. But you can't use the USB input for routing.
You have 64 Inputs on each USB64. You can wired push buttons, switches or pots on each input. It doesn't matter what input you want.
c) yep the case is self made. Also the front panel. It's a 2mm aluminium plate with a self glue film on it.
d) I use an internal 12V 2,1A Power supply for all Doepfer units and a DC/DC converter from 12V to 9V for the Axoloti Core.
You can powered the USB64 via USB Input but not the MKE and the Wheel Electronic. And you can't route the midi data for both USB64 via USB. Only via DIN Midi in and out.
And .... Thanks for your kind words.