Release 1.9.0-RC1

Hi there everyone, another major release is here - v1.9.0-RC1 aka “The X marks the spot”.

This release finally enables the Duo X CV and EXP ports.
We added a couple more things surrounding CV as well, so Duo users also have a reason to update. :slight_smile:

Please note that this is a release candidate.
That means it might be stable, but needs more testing first to make sure.
If no issues are found in around 2 weeks we’ll release it as stable, otherwise we’ll do a RC2.

So, what’s new?

CV support

This is mostly concerning the Duo X.
The physical ports now have their software counterpart displayed in the pedalboard.
There are 3 inputs - 2 for the CV inputs and a special expression pedal one.

The expression pedal input (on the pedalboard) will output either 0 or 0-5 depending on the device settings.

On the Duo X device menus, there are now options regarding CV.
For the inputs, a switch for toggling between CV and expression pedal mode. (CV by default)
For the outputs, a switch for toggling between Headphone or CV. (Headphone by default)

There is also the setting to toggle between signal on ring and signal on tip for the expression pedal.

Addressing arbitrary parameters to CV out ports

Related to the previous item, it is now possible to address arbitrary plugin parameters to a CV out port.
This is the case for both hardware and plugin CV ports.
It is also possible to address multiple plugin parameters to the same CV port.

You can manage which CV out ports are addressable by clicking on the “Manage CV Ports” button on the top of the pedalboard constructor window,
and then enabling specific CV ports that you want to use.
You can give them a custom name so that they are more recognizable.
Then in the addressing dialog, you can pick that CV port from a dropdown list.



Smooth peakmeter color transitions

We have found that the way the peakmeters are used often confused new users and as a result many didn’t play with the optimal gain settings and headroom.
We have decided to tweak things a bit and also make the transitions between the colors smooth instead of static.
With this, the LEDs will also give a better indication of where in the range the signal is instead of being in one of the 3 options there were before (green, yellow and red).

So in v1.9 onwards, the following ranges are applied:
-inf dB to -40 dB → LEDs off
-40 dB to -6 dB → green fade in
-6 dB to -1 dB → green fully on, fade in of yellow
-1 dB to 0 dB → red

When the value reaches anything above 0dB (digital clipping) the LEDs will blink red just as they did before, to give a clear indication that the audio is being distorted.

There’s also quite a few more changes and tweaks.
You can read the full changelog below.

Because this release is still under testing, it won’t appear as an update in the web interface just yet.
You’ll have to manually download and apply the update file if you wish to try it out.
(Release testers, also known as ‘group 1’, will receive this update as usual)

Here’s the manual download link:
Duo X:

The upgrade procedure is explained at the top of our releases page, here:

Here’s the full changelog:

  • NEW: addressing a parameter to a CV output port
  • NEW: reading from and writing to hardware CV ports
  • NEW: compact pedalboard list view
  • fix device true bypass mode display not updated when changed via web gui
  • fix missing range for BPM and BPB MIDI CC addressings
  • fix pedalboards showing old stuff after importing user backup
  • show CV port information in plugin info dialog
  • show MIDI program number/indexes near snapshot names
  • smooth peakmeter color transitions
  • improve UI for plugins expanded multi-input jacks

Duo specific changes:

  • add led blink when pressing footswitches for triggers and enumerations
  • brought back direct headphone monitoring option
  • don’t show cpu stats on the Duo, not available (developer mode)

Duo X specific changes:

  • NEW: potentiometers calibration mode
  • add CV related options to device menu
  • enable SPDIF output (coaxial)
  • hide inactive pages in device by default
  • initial support for rk3399 CPU (in addition to the current imx8mq one)

A note for developers:

We changed a bit how CV ports work in the plugins.
Plugins must define output port ranges and set “mod:CVPort” as their type in order to have their CV ports appear in the pedalboard.
Only 3 ranges are officially allowed:

  • -10 to 0 (- Unipolar)
  • -5 to +5 (Bipolar)
  • 0 to +10 (+ Unipolar)

We hope you’re enjoying your MOD Duo and/or MOD Duo X.
Let us know if you find any issues.


We are working on documentation regarding CV.
There are some screenshots missing, but otherwise ready for feedback.

Let us know what you think, if something is not clear, etc.

Just to clarify does the expression input work for MIDI now too, or just CV?

not sure what expression input means for MIDI, so I must assume the answer is “just cv”.
basically with the duox, you can connect a regular expression pedal (via jack cable).

just make sure to get the device settings right

1 Like

Thanks for the update. Good to see CV and S/PDIF available.
Will the MOD Duo X get the peak meters feature enabled part of 1.9 or do we have to wait even longer?


i’m trying S/PDIF output, but there’s no signal. I connected the Duo X’s mini jack output with RCA (Cinch) input of NI Komplete Audio 6 USB audiointerface by using left RCA phono plug of a stereo mini jack to double RCA phono cable (similar to this one:

NI Komplete Audio 6 has been set to synchronize with Duo X (slave mode) and SPDIF SYNC LED turns orange (which means sync is ok refering to manual on page 25). Configuring it to use its internal clock has no effect on missing signal from Duo X.

Issuing alsamixer on Duo X via SSH revealed that S/PDIF Enable switch is disengaged, but even though when it’s engaged there’s no output. Running amixer shows the following:

Simple mixer control ‘SPDIF Enable’,0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control ‘SPDIF Mono/Stereo’,0
Capabilities: enum
Items: ‘Stereo’ ‘Mono’
Item0: ‘Stereo’
Simple mixer control ‘Validity Bit Control’,0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]

How to interpret these values? And what to do to get S/PDIF output working? Am I using wrong cables?

There’s an option to enable/disable Audio peak meters in this RC, which switches hardware peak meters on and off. If this is your question.

Thanks for the reply. My question was more about getting a proper fix so that we can actually use the peak meters on the DuoX. I’ve now been told that the fix requires contacting support.

I’ve tested this release with a Surface tablet. Here are the problems that I’ve found:

  • Midi ports list shows connected midi controllers, but they work even unticked
  • “Manage CV ports” label doesn’t turn off when clicking on it again
  • Choppy parameter changes when controlled externally via CC messages (as opposed to using the knobs)
  • Prevents Maschine MK3 from loading when connected to the same PC via USB
  • Tapping on check marks next to CV inputs does nothing. They’re grey with the tick mark.
  • Adding pedalboards from doesn’t work, despite the message saying that it was successfully installed
  • A lot of GUI functionalities don’t work on a surface tablet with a Chrome-based browser (pan, add generator/pedal, patch cables, etc.)

Feature requests

  • Make it possible to have 2 controls at once on a synth parameter. Per example. I’d like an external device to send CC messages to a synth, but I also want to be able to take over locally
  • USB midi. It’s currently not possible to just connect a PC to the device and control it from a DAW. You need a MIDI interface.
  • Bluetooth midi. It seems the current implementation is oriented towards loading the GUI, but there are some interesting BT MIDI devices out there.

This RC1 seems to be working great on my Duo so far. Only two slight niggles (which might be totally unrelated to this version):

  • After the first upgrade and reboot, I enabled the “Copy mono output buffer to unused channel”, clicked “Reboot MOD”, and then it got stuck during boot. This was fixed by a power cycle.
  • When I save a pedal preset, the dialog is titled “SAVING SNAPSHOT” - surely it should say “SAVING PRESET” since snapshots are across the whole board not just for one pedal?

Did some additional testing with another PC and a device connected via CV.
I was able to use a LFO to send CV and I was able to receive 2 CV signals to control generators inside the Duo X.

One thing I couldn’t find is a CV to midi converter to make it possible to play notes on the internal generators.

Some more bugs:

  • GUI doesn’t load completely without network connectivity. Right side connectors were unavailable
  • Knobs of all CV modifiers were visually broken.
  • Playing with Noisemaker froze the device

Upon further testing, I saw some unexplainable CPU usage spikes with this release. I downgraded and they’re gone. I can’t yet be 100% sure it’s related to the new release, but I have a gig tomorrow so I can’t take any risks. I’ll upgrade again after and see if I can confirm the correlation. If there is an easy way to debug this let me know. I did ssh in earlier before the downgrade to see if I could spot anything, but for some reason it didn’t occur to me at the time that running top might highlight the culprit.

Hello @aspiers,

I want to know what that was. I didn’t ssh into my mod but I wondered about the 100% CPU high load. After rebooting it was back to normal workload. Hope that helps…

Greetings and God bless, Marius

You mean rebooting to 1.9 or did you downgrade too?

Hello @aspiers,

I simply rebooted and under a comparable pedalboard like Caps Multi Effects uses 64% to 65.5% CPU and 15.3% RAM at 128 frames.
I am not a programmer but I thought a reboot could do the trick. I also work with different monitor resolutions that might have been the culprit for me but also could be totally unrelated…

Hope that helps.

Greetings and God bless, Marius

Can anyone check if S/PDIF is working? Or does the MOD Team have a clue? I’m stuck. :pleading_face:

please write to
If you can include details on how or to what you are connecting the Duo X, would be very helpful.