Noobie trying to understand - MCU Protocol

Hi everyone.
I just recently got a DAW Controller, Icon P1-M. I seem to understand how it works in general. However, my dad (that also produce music, mix) has also made the decision to implement a DAW controller in his workflow. He is smart, but not too smart when it comes to the techy side of things, so he then calls me over to help him (previously with things such as implementing macros and such).

So, he had gotten hands on a SSL Nucleus MK1 . Seems like a great unit. However, I have a hard time to find some of the functions that I have on my Icon P1-M. To give an example, I can control my channel strip section in Cubase with my V-pots on the Icon P1-M, but I can’t seem to find how you do it with the SSL Nucleus.

That lead me thinking, just because it is working via the MCU Protocol, perhaps it does not have all the functions? Originally I thought that if it supports the MCU Protocol, then all the functions are there, but now, in my mind, it would make sense that some controllers would not have every single function.

So the question is: Are certain MCU Based DAW controllers “limited” in the way that it does not support every function?



MCU Protocol is just a set of MIDI Messages and recomendation, how should the DAW interpret the MIDI Message.

So by default, the faders are sending PitchBend on Channel 1-9. By default, they control the Volume faders of the Channels 1-8 (plus the Master Fader on Channel 9). Then you have the Channel < and Channel > buttons. They should move the bank by 1 channel. If you press the Channel >, then the Bank is Channel 2-9, so the faders are controlling the Volume faders of channels 2-8. But this is the default settings. You can press the Flip button. Then the Faders are controlling the parameters, which were originally assigned to the V-Pots (encoders).

By default, the V-Pots are controlling the Pan. But you can press a button, to control the EQ, or the plug-ins parameters.

After the years, every single DAW modified the MCU to their needs. So the functions are not exactly the same in every DAW. But in general, they work similar.

And also every HW vendor modified the hardware itself. So some of them doesn’t have the full set of buttons or displays. So it might happen, some feature is not reachable from all hardware. There are some HW withuot the Navigation keys, some of them are missing the Track Selection buttons, some of them are missing the switcher to the Send levels, etc. Some of them are using only 1 channel, not the bank of 8 channels.

So yes, you are right. Not every hardware has to support all MCU features and functions.

If I’m not mistaken, to control the Channel Strip, you have to press the button, which was originally labeled as Dyn (on the original Cubase sheet). I can see the Dyn button on the SSL Nucleus. So after pressing this button, the encoders should control the Channel Strip the very same way, you do on your P1-M. If the Dyn button doesn’t do, what do you want to, try the Instrument button (this is the original Mackie Control label), please.

In any case, once you press the button, it should send the MIDI Note A2 at Channel 1. This is the button, which switches the Encoders to control the Channel Strip in Cubase (at any Mackie Control device).

Thank you @Martin.Jirsak
Very well explained. It feels like I moved several steps in understanding this concept.

I will try this. By the way, I read something about Cubase/Nuendo having two modes, Cubase/Compatibility mode? Is this something that may effect what functions I may or may not be able to do?

Many thanks!



Several devices (including SSL Nucleus) supports Mackie Control but also Mackie HUI. They are similar to some extension, but not completely. If you choose Mackie Control on the hardware, you have to choose Mackie Control (not HUI) in Cubase too.

I would recommend to use Mackie Control over Mackie HUI. Mackie Control is newer with more options.

I do not think this is what I am referring to. I am referring to what mode that will be used within the Mackie Control.


This must be some older Cubase version, isn’t it?

Go for the Cubase mode, please.


Yes, it is my father I am helping, and he is using Nuendo 11.

Nothing is happening when pressing the DYN nor the INSTRUMENT button on the Nucleus.
In the Nucleus Software it says unassigned, so it must be why? However, I do not find a DAW CMD within the software that seems to match what I am trying to do. I have emailed SSL about this, waiting for a response.


Do you use the Mackie Control in the Nucleus software for Cubase? If you press the button, does it send any MIDI Message? Which one?

I use the MCU protocol within the Nucleus Remote.
Which button are we talking about exactly?


Exactly the Dyn or the Instrument button.

While the DYN button does not do anything, the INSTRUMENT button opens up the VST Instruments. However no midi message is being sent, checking both the inout/output activity bottom right in the project window, and observing the midi monitor insert. Other things such as rotating the V-pots outputs midi.


Which button does the trick in your site?

Pardon me for not understand Martin, but what do you mean by do the trick?


Sorry for not being clear.

Which button do you press on your iCon hardware to control the Channel Strip by the V-Pots?

It is the touch screen button called DYN/FX/AUX


I see. Then again, I would expect the Dyn button on the SSL Nucleus would do the trick.

As would I, but it does not do anything on the nucleus… Is it a Nucleus-Nuendo issue?


I don’t think so. You just have to find the button, which sends the A2 MIDI Note to switch to the needed mode.

We’ll see if we find any success in doing that.

If I understand correctly, the differences between “Cubase mode” and “Compatibility mode” when it comes to mackie control, is that the Compatibility mode does not have all functions, is this correct?