Pedal board selection random freeze


Mod Duo - I use a different pedal board for every song selected by midi program change. Sometimes the selected pedal board does not load and the output led’s flash on and off with an audible pulsing sound.

How to reproduce

I don’t know how to reproduce it because it happens randomly with different pedal boards, most times it works ok, I can for example maybe make 100 program changes with no problem then out of the blue with no apparent reason this bug happens. If I select another pedal board and then re-select then it loads ok.

Expected/suggested solution

Replace this text with how you would expect this to work.

Additional information

Open the controller menu (hold left knob down), navigate to Info > Versions and write down here the version.

  • release:

Also provide some information about your system if possible.

  • Operating system: (Linux, Mac or Windows)
  • System version: (Windows 10 or Mac 10.10, etc)

I remember seeing a behavior like this sometimes. In my case I believe it was caused by overloading the DAC or some kind of audio signal panic.

I had several pedal boards using input 1 for guitar and input 2 for mic. Then after reading in the forum about input 2 being slightly less noisy, I started rewiring my pedalboards to switch guitar and mic inputs. Sometimes I would accidentally call up a pedal board that I hadn’t rewired yet and the guitar input would be going to the mic channel where there was a ton of gain and then the device would go into that state.

I wonder if there some timing or initialization issue where a portion of audio frames get out of sync with the expected state and “slip through”. This sounds difficult to track down like you said.

I did exactly the same mic into 1 guitar in 2 then re-wired to switch inputs but I don’t have any pedal boards left with original wiring all have been re-wired and this problem happens randomly on different pedal boards which usually load ok.
Your suggestion about initialization made me wonder if this could be caused by audio passing through while pedalboard is loading for example if during the few seconds of program change I pluck a guitar string to check tuning allowing audio signal to be present while loading. I don’t know if this is the case but I wonder.

It would be great if you can confirm that the issue is caused by this. This would help us a lot with the troubleshooting and therefore getting it fixed.

After testing I can confirm that the error occurs with or without audio present.

I can also confirm that it is very random, I did one test where I got 3 errors in approximately 50 program changes but in another test I got no errors in approximately 200 program changes exept one where the output LEDs flashed once but then corrected itself.

Happens to me too. I’ll try to investigate deeper but I suspect that connection with WEB GUI (via USB) is involved (like other random freezes that happen when you mix usage between WEB GUI and MOD controls).

As a side note, is it an expected behavior that when the pedalboard list (or snapshot list) is shown on the MOD display and a snapshot is changed via MIDI, the change is not reflected to the list even if the snapshot has been selected in the background?

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In my case midi program changes do not work at all when WEB GUI is connected via USB which is a pain in itself as if I want to make global changes to around 30 pedal boards I have to select each one manually from the GUI pedal board list which is very time consuming and would be much quicker if I was able to select them in the GUI by midi program change however that is another issue. The midi program change problem I am experiencing occurs when not connected to the GUI.

This is actually bad news @Ched :confused: not knowing the source of the issue will make it way harder to find and fix.

I’m not sure what @redcloud mentioned when he said that, but this is the expected behavior. It is related to some priorities that the system needs to take and for now, this is required to be this way. Maybe @redcloud can clarify what he meant.

I would say that no - because if I got it well it doesn’t make a lot of sense to be this way. I guess you found a bug that may be around since ever :grin:

I did further tests today and got several errors most seemed to be centered aroud one pedalboard but randomly others. One interesting feature is that I noticed that the pulsating LEDs and audio was at a different tempo for different pedal boards which made me think that this could be caused by a plug in perhaps a delay pedal which may explain the tempo difference.
I have attached screen shots of two pedalboards which are named A & B, Pedalboard A is the one that seems to error most and B being one of the random selections. Pedalboard A LEDs and audio pulsed quite fast while pedalboard B pulsed a little slower. Note that the Stereo Echo plugin is used in both and the delay time settings seem to match the difference in the tempo of the pulse, this may be a coincidence but could it be the cause?

If so then the midi selection may be a red herring, I don’t think it has ever produced the error when selecting within the GUI but my next step is to see if I can create the error using footswitch selection.

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I can now confirm that the errors occur when selecting pedalboards via foot switches so the problem is not midi related as I first thought. If it is a plugin causing the issue then the randomness could be explained by the fact that I have some of the same plugins on all pedalborads. Although the fault occurs on random pedalboards the first screen shot above is the most common pedalboard to create the fault.

This are actually quite important discoveries for the troubleshooting.

As you stated this, I removed the MIDI from the title of the thread so it does not mislead other readers. Hope that’s ok.

Maybe something related when the plugin re-loads (?? just guessing here). I will pass it to the developers.

I’m trying to reproduce this bug but it would be really helpful if you could share some of the pedalboards that trigger the freeze using the share function.

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OK, I’m not sure how to share pedalboards to a bug report
but I will investigate

Hey mate,

On your gui, in the board constructor, there is a share option that uploads the board to the website.

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OK I have shared 3 example pedalboards (thanks Elk_wrath) but note that this bug shows up randomly on any of my pedalboards but these 3 examples just happen to be the last 3 that triggered the bug but they don’t always trigger the bug.

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can you post here the links for those pedalboards? It will make things easier for everyone to try it :slight_smile:

EDIT: if you couldn’t because of your trust levels in the forum, I just raised them. So, hopefully, now you can. Let me know


Heey Ched, I’ve tested loading your pedalboards a bunch and so far, no freeze. May I ask you what version you are using on your Mod Duo? I would suggest you to try the new Release Candidate:
Release 1.11.0-RC2

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

Let us know if this fixes the issue or not!

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Yes its randomness makes it difficult to reproduce sometimes I can’t make it happen in a hundred selections other times it can show itself two or three times within 20 selections and random pedalboards so I am not surprised that you have not been able to reproduce. Yesterday I discovered that almost all of the plugins I use have new versions, I wasn’t aware of that as I don’t regularly look in the plugins store and there doesn’t appear to be any other type of notification that a plugin has been upgraded. After upgrading what seemed like around 30 or more plugins (I didn’t count) I did a lengthy trial and didn’t get any freezes so hopefully that may have been the cure but due to the randomness as described above only time will tell. My Mod Duo is running on version 1.10.4 and GUI states “system is up to date” but I will hold off upgrading to 1.11.0-RC2 until I’ve had more time to evaluate if the plugin upgrades have cured the bug.


Bug seems to have cleared after several plugin upgades, due to the random nature of the bug I’m not going to declare it fixed yet I’ll give it a while longer but so far looking good