Save hardware input/output levels

yeah, something like that. very unpleasant if you expect 50% volume but suddenly it changes to 100%.
on the Duo X, the output headphone optionally acts as CV out. so an alsamixer switch could make the headphone receive 5v

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Ouch !

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I am reviving this thread to be a bit more specific.

What I am really interested about is really the input levels. I don’t thing there is a risk of damage here, is there?
Basically, with some pedalboard, I’m using input two of my Duo for a microphone. On another, I use it for a bass. On another for some line level input. Changing them manually at every change of pedalboard sucks.

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You can use different User profiles. But that will indeed not change when you change pedalboards, you need to change it in the settings. Think about the User Profiles as something that you would have one for each of your different music projects.

Today I´m feeling like a witch doctor!!!
I’ve brought back to life two old threads already.

Hello @Azza
How did you manage your needs regarding the hardware input/output levels on this thread?
I’ve been using a user profile with -12db on both inputs and 0db on both outputs but I’m not sure off which kind of db metering scale MOD uses. Is it dBv, dBFS, etc.?

I´ve been reading several other threads regarding this but is so much info and I’m yet not sure of anything.
@falkTX could you clarify that to me?

Al the best.


Hello @rogeriocouto Rogerio and @falkTX Filipe,

I don’t know why the DuoX user guide is missing the exact entries because the Duo User guide has some info. Is it the same at least for the LED part on the ModX?

@falkTX, correct me if I’m wrong:
Be aware the LED metering is on the analog side before the A/D conversion for the input, but
on the digital side before the D/A conversion for the output.

Greetings and God bless, Marius

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Hi @mj_prod

You lost me… What this has to do with the type of Db metering scale? :thinking:

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Hello @rogeriocouto Rogerio,

oh, I’m sorry, I didn’t understand your issue before posting.

I think internally it is dBFS.
For the output you can use some of the test tone or noise plugins and measure the volume on the outputs.

Greetings and God bless, Marius

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I also think it´s dBFS but I want to be sure of it so I can calibrate the signal flow accordingly.
Guessing what is going on in the audio flow it is not a good approach and I’ve been doing this for far too long.

Thanks for stepping in.


Hi @mj_prod

I tried to test the input level but could not come to any conclusion so far.

  • MOD Duo inputs set at -12dB
  • Sent a -20dB (dBFS) signal
  • The reading with the x42 level meter plugin was at 18.5 dBFS
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I’m not sure what you mean, the MOD Duo X user guide page has exactly the same info here - and yes, they are the same. Am I missing something?


Hello @jon João,

I simply overlooked this part in the wiki user guide, sorry.

Greetings and God bless, Marius


No worries :slight_smile:


@rogeriocouto generally we use dBFS. If there’s a pattern breaker it would be in a plugin


Thanks again @jon

I tested the DUO input levels extensively yesterday sending different signals (white noise, pink noise and a 1Khz Sine Wave).

The readings on the MOD GUI were always around 3dBFS louder than the sent signal.
Now I need to figure out where the signal is being amplified (MOD DUO input or Scarlett 4i4 output?).

I suspect that this related to different calibrations of the units.
On this video section below there is a nice example of that.

To test that, I generated (Daw Oscillator Plugin) and recorded a -18dBFS 1Khz sine wave on my DAW, uploaded to the MOD “Audio File” plugin and played.
The reading inside the MOD DUO was exactly the same (-18dBFS), so my guess is that the MOD DUO is calibrated at -18dBFS.

Can you confirm this information for me?
I couldn’t find any mention to that on the documentation neither on any threads here at the forum but maybe I’m missing something.

Next test will be to record the input of the Scarlett with a -18dBFS signal and upload the result to the MOD DUO to check how the DUO will read that.


Finishing the tests…

  • Recorded a -18dBFS 1k signal with my Scarlett 4i4 and uploaded the audio file (.wav) to the MOD DUO.
  • Played the file with the “Audio Files” plugin and measured with the x42 “Level Meter” plugin
  • The result reading inside the DUO was exactly -18dBFS, so I conclude that both units (MOD DUO and Scarlett 4i4 3rd Gen) are calibrated the same.

The +3dBFS could be related to several factors like:

  • how the signal on the first test was sent from the Scarlett to the MOD DUO
  • how the input settings on the DUO are set
  • how the output settings on the Scarlett are set

I think that the important thing to note on this tests is that both units perceive the recorded sound reference in the same way and therefore we can just set the levels to taste* and be happy!

*Just avoid digital audio clipping and if using the MOD DUO keep CPU usage to around 70% to 80%.


I’m not sure about this, but maybe @Jan can give us an accurate answer.

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I think things are getting mixed up here a bit.
dBFS is used in the digital domain, and does not have a real world value, while for instance dBu does.

So it heavily depends on the input settings how things will be scaled digitally.


Thanks @jon and @Jan

I was researching this subject on the internet and it’s very confusing to me.
It looks like that do not exist just one standard but a few on this matter and depends on what each manufacturer is aiming for in terms of headroom.

I think the simple question is…

How setup the input and output levels (device settings menu) of the DUO (and other MOD devices) to get the best signal to noise ratio:

Audio inputs
Line level: ??dB to ??dB
Mic level: ??dB to ??dB
Instrument Level: ??dB to ??dB

Audio Outputs
Line level: ??dB to ??dB
Mic level: ??dB to ??dB
Instrument Level: ??dB to ??dB

With this ballpark information at hand users can infer how to manage their own equipments.
The Wiki info for the MOD DUO on this subject are confuse and outdated.


I didn’t :smiley:
I was really busy with other stuff and didn’t do more than adding a hardware passive volume button downstream of my Mod Duo for quick adjustments. But I don’t play live and when I record, I’ve got all the time and options in the world to adjust my output volume.

For input, I just play with the controls.