Plaits with frequency locking and aux crossfade (alt firmware)

Now I see that I wasn´t clear about that.
First I tried modifying the firmware to use the Freq Knob to control decay, because there were some clear instructions from lylem on how to to do that.
After doing that, I´ve read some older instructions from lylem, that where not supposed to work on top of this FreqKnob/Decay modification, on how to use te Model CV input to modify the Decay. So I wanted to try this but using the FM input instead, as I rather keep using the Model CV + the Freq knob to mix Main + Aux.

Keep the changes that I suggested that affect the FM input and decay, and bring back the original code that set the crossfade parameter!

I actually worked on top of lylem´s code that set the crossfade parameter.
I just compared both just in case, and the only modifications are the ones that you suggested, so I guess they might be interfering with the Freq/knob crossfade parameter.

According to this, this is a picture of what i´ve modified (left original, right modified), just in case this helps:

You probably have disabled kAuxCrossfade in another file.

I only modified the (the picture i sent + this 2 modifications):

and voice.h has the kAuxCrossfade set to true:

If you don´t suspect that the modifications you suggested could made the Freq Knob to stop working as a crossfade, then I might made a mistake somewhere else. I cant imagine where actually, but i can start all over again just in case.

A post was split to a new topic: Plaits internal envelope

Hello! I have no experience coding and I’ve been looking for a Plaits firmware where I can control the env decay through the level input on the module. I asked this on a different thread Plaits: MODEL cv to Envelope Decay mod - #6 by chart but haven’t received an answer and I’m wondering if anyone has done this before and would be willing to share the wav file with me.

Thank you !

Hi All,
I really like the option to lock the frequency, but I lacked a visual indication on entering and exiting this mode so I added some code for that.

I will send my code to Lyle In order to merge it in his code




Hi all - I’ve made a few revisions to my two existing Plaits alt firmwares, and I’ve added two new ones as well. Thanks @Shayshez for reaching out and providing some of the code+ideas, and the impetus to work on this firmware again!


  • All frequency locking alt firmwares have been updated with LED indication for frequency locking. Red for locked, green for unlocked. In color-blind mode, it’s unblinking for locked, and blinking for locked.
  • With frequency locking now having LED indication, it seemed reasonable to reduce the
    time you have to hold down both keys to lock/unlock frequency
    - it has been reduced from about 2 seconds to about 200 milliseconds.
  • It is now possible to recalibrate the module even with the alt firmware installed. Simply keep holding down both buttons for about 5 seconds to reach the calibration process. Note this is a longer delay than specified in the Plaits manual; I thought it was a good idea to have a longer delay because with frequency locking using the same combination of keys, I didn’t want people to end up in calibration mode accidentally.

New versions

  • I put together a new version of the firmware where aux crossfade is under CV control, repurposing the MODEL input
  • I put together another new version of the firmware where the LEVEL input is repurposed for CV control of the decay of the internal envelope (this one’s for you @chart)

For everyone’s reference, here are download links to all the versions that exist:

  1. Frequency locking + manual aux crossfading using the locked Frequency knob (link)
  2. Frequency locking + manual octave shift using the locked Frequency knob (link)
  3. Frequency locking + manual aux crossfading using the locked Frequency knob, plus CV control of aux crossfading using the MODEL input (link)
  4. Frequency locking + manual aux crossfading using the locked Frequency knob, plus CV control of decay using the LEVEL input (link)

With these new features there are getting to be too many possible variants for me to keep up with uploading firmware versions for every possible combination, sorry. But if someone needs a different combination let me know and I’ll try to make it happen for you when I get around to it. Or maybe someday I’ll figure out a good way to do a super-firmware (but don’t hold your breath :slight_smile:).


Here’s a combo I’d love see if you can get around to it:

Frequency locking + manual octave shift using the locked Frequency knob, plus CV control of aux crossfading using the MODEL input

Thanks for all the great work! :pray:

1 Like

Thank you sir, absolute legend !

If you ever do want to tackle a “super” version it could work something like this:

While holding the first button (as if you were adjusting the lpg) turning the timbre cv knob chooses what the model input controls, turning the fm cv knob chooses what freq does when locked, turning the morph cv knob chooses some other new functionality (maybe switching the morph and harmonics cv inputs or something).

Just a thought, and thanks again!

@jeaux thanks for your thoughts on the super version, I’ll give those some consideration.

In the meantime, here is the wav file for the version you requested (Frequency locking + manual octave shift using the locked Frequency knob, plus CV control of aux crossfading using the MODEL input). Please note that this combination of features requires a little bit of compromise: since there is no longer a way to set the middle point (i.e. the amount of aux crossfading with no CV input or 0V input), it had to be hardcoded to 50% (since the MODEL input is bipolar, -5V to +5V). In other words with this firmware, when not using CV, the AUX output will have a 50-50 blend of the main and aux models. In an ideal world it could default to 100% when the there was no cable inserted in the MODEL input, and 50% when a cable was inserted, but this doesn’t appear to be possible (see eurorack/voice.h at d926b3238db0ff293510f64f877bad03e5a3ffd3 · pichenettes/eurorack · GitHub, there is no engine_patched). I didn’t have time this morning to figure out if it’s even possible to add jack insertion detection for the MODEL input in software or if it’s a hardware limitation, but I suspect it’s the latter.

Anyway, enjoy!

It’s a hardware limitation indeed, the required signal is not sent to the jack.

1 Like

Makes sense, regardless, thanks for the update! I also noticed this morning you did a similar octave control firmware for Rings, I will definitely make lots of use of both, cheers.

1 Like

This is amazing, I will try it as soon as I get home next week!
Thanks again.

1 Like

Just had an idea that would solve the model bipolar cv issue. When the cv is zero aux out is normal, positive voltage crossfades with the main out, negative voltage crossfolds (or some other Warps like algorithm). That way unpatched the aux out is normal and you could implement another functionality.

Just some food for thought.

Edit: might make more sense flipped:
-5 to 0 : crossfades from main to aux
0 to 2.5 : crossfades from aux to ring mod
2.5 to 5 : folding or other timbral effect

Hi all - I finished putting together the unified “super” firmware, and I’m starting a new thread for that since I don’t want all the old links in this one to mislead anyone going forward. If you have any further questions or feedback, please use the new thread, thanks!

1 Like