Attention! loud noise!


Worked on headphones on a pedalboard:

and suddenly my brain has been kicked out by a incredible loud noise. Output LEDs went red, I threw away the headphones and screamed. Immediately switched off the device. Sadly, because it is hard to know what went wrong this way. Swiched it back on and all was fine. But now I´m afraid of my headphones:(
Guys: no matter what went wrong, this is dangerous and shouldn´t happen!
Only BETA Plugin in this Board is the random-generator… from Mod Devices.

How to reproduce

The board works on low levels for having enough headroom and because a huge dynamic range is what I need for Soundart-installations this board is built for…
The only thing I could imagine went wrong was me doing some rearranging in the libraray and banks at the very moment.
Perhaps the DuoX missed hardware-definitions/ user profile and gave me some nice +10V CV on my ears? But this wouldnt sound like deep pinknoise would it? I dont know and at this moment I dont care because the noise scared the hell out of me and I dont want this to happen again.
My ears are all I have and I need them to make a living.

Expected/suggested solution

Don`t let this happen on a concert with a massive PA-system!!

Additional information

Version: V1.9.2
Restore: 29C3BBA
System: 8307141
Controller: 8403942

Firefox 81.0.2
MacBookPro 10.14.6

I’ve experienced this several times recently too and it feels like an important issue - I’m glad you reminded me of it. I’ve been fortunate to be using a PA at family-friendly levels but when it happens it’s a moment of panic reaching for the mixer master volume. The causes are likely due to some combination of feedback, gain-staging, and non-linear effects. I often run a mic and guitar into the Duo. Most of the time this happens right after loading a pedalboard; I think once or twice after it was loaded for a while. Same result - red lights flashing, with a continuous awful clipping/wailing/feedback noise at least several dB higher than the performing levels. Enough to scare the kids across the house and/or lead to some mild embarrassment when jamming with a friend :blush:

Is there anything that can be done on the device like adding a built-in limiter at the outputs? I know @solobasssteve has in the past recommended using the Calf Multi-band limiter and I’ll take a more serious look at that - previously when I’ve tried it, it was taking up precious CPU and there’s no documentation. Maybe something that could be disabled in system settings for users that really know what they’re doing? I’d much prefer that the system disables audio output in this scenario rather than risk damaging equipment or hearing.


no suggestions from MOD Devices?
should we do more testing? how?

My first guess would be a bug in one of the effects plugins. I remember a similar problem from one plugin I compiled myself on the computer and it turned out to be an error in the code that divided by a float approximation of zero (or something like that, don’t remember exactly).

To protect against loud output, put a limiter at the end of your effects chain or alternatively a compressor with high threshold and the highest ratio. Of course, this will slightly affect your overall sound so try a few different settings. Or, if you want to be extra safe, place a limiter or separate mixer behind the MOD.
Anyway, did you manage to reliably reproduce this issue? If so, how? You might also try to bypass each effect one by one to figure out which one is problematic.

Of course, it could also be an issue outside of the plugin space (like CV/headphone output, firmware etc.) but it’s more likely related to a plugin IMO :thinking:

1 Like

It is for sure a bug in a plugin, we just need to find out which one.
We have a special internal build that we have been using to catch these sorta issues (running the entire audio server through valgrind, making it unusable for realtime audio but great for spotting issues right away)
We have been running that special build on some plugins and collecting all the small things that need fixing.

Sorry for late response here, lots of stuff to handle at the moment, but we will check this soon too!
Probably all at once in a big sprint.


Hi Falk, thanx for your reply!
The noise-terror just appeared once in my case- and I didn´t push my luck after that;)
I uploaded the board (see 1st post) and there only is the random generator in BETA.
I´m still scared of the board and don´t know how to move on. I put the “limiter” (stereo Compressor) at the end AFTER the noise happened. Also now I readjusted the gain-stages thoughout the patch so the overall level is now higher and I could lower the main output. that way the noise- if it happens again- won´t be 1000 times louder than my signal… just about 100 times;)

Thanx for working on the issue, I´m sure you got a long list of things to do!

put in the newest Version V3:

by the way: how can I delete a Pedalboard online?

thanks! I did try the pedalboard btw, and confirmed the issue.
I still have a browser tab open with a different one where the same thing happens.

did not check if there are plugins in common between them.

We can do it from our side, there are no public controls for it right now.
Which one you want to delete?
@acunha usually takes care of that.

1 Like

only the STEREO AMP …

I´m discovering a new problem right now.
I am not able to load ANY Pedalboard via the online-library.
It shows:

…but nope. No new pedalboard in my library.
Restartet and Rebootet the MOD.

Version: V1.9.2
Restore: 29C3BBA
System: 8307141
Controller: 8403942

those pedalboards are only loaded, not saved in the system.
If you like any of them, save before loading the next one.

thanx, but they are not even loaded.
also the boards in BANK/ my own folder are not equal to the ones in my device…
[edit: this is not the case sorry- folder shows correct boards]
it seems the GUI is at an older stage…
will backup everything now an reinstall the firmware.

Firmware doesn´t install. Perhaps because it´s already the newest version?
Board still doesn´t load:(

manual install is broken in 1.9.2 for macOS, something we are fixing in 1.9.3

any Idea when 1.9.3 will be released?

Would it be an option on the MOD side to add under the hood a default limiter at the end of the signal chain that could of course be disabled by users knowing what they are doing? We don’t want anyone to be injured or any hardware to be fried because of a faulty plugin. Would that be something you’d consider @falkTX ?

Also, on a different note, I’ve had several occasions where the duo totally froze with no output and no hardware control working at all. It all worked well after a reboot, but I wouldn’t want that to happen in the middle of a gig. I think this has started to happen since I upgraded to the mainline kernel.


I’ve had similar problems when putting when putting FX after the vocoder.

!! interesting !! could you give some more details?

Something like that is already in the plans :slight_smile:


What detail do you need? Is there place that describes the procedure for reporting bugs here? I do have a few after using the modduo for a few months now…