Mackie Control selected channel fader

Hi,

I've noticed that in your Mackie Control you have section "Selected channel" which offers manipulation of the selected channel in DAW and it works great! I wasn't even aware that such functionality exists in Mackie Control protocol.
Now I wanted to add a hardware rotary MIDI controller to my desk to supplement the fader up/down function in addition to stream deck. I mean, it's faster and more convenient to turn a rotary dial left/right than to keep pressing stream deck buttons for this.
So I was wondering, can you please share with me, which MIDI events is this sending? I mean specifically Selected Channel -> Fader -> Up/Down. Also, is this based on any input MIDI data at all? In other words, is two-way communication with a DAW necessary for this or not?
Like, for example, if I just want to send Mackie Control transport stop/play, there are well known MIDI notes that I can send to DAW and it will work. Only if I want to know the state of that transport is when I would be needing MIDI in, but if I don't care about the state and just want to control it, then MIDI out is sufficient. Since I didn't find specifications for this Selected Channel -> Fader -> Up/Down, I'm wondering if it can be done with just MIDI out, or will it require MIDI in as well.

Thank you for your help.

Cheers!

Hi,

There are no commands in the Mackie Control protocol to control the selected channel.

When a channel is selected, the daw sends a command saying which channel is selected. The plugin keeps track of this and internally saves the channel number for the latest received "channel select" command.

When you use "Selected channel" buttons on Stream Deck, the plugin knows which channel is selected and will send the standard channel commands for that channel.

So, to implement the same thing using other devices, I'm afraid you not only need MIDI in and out, but you also must implement the same local logic to overcome the lack of "selected channel" functionality in the Mackie Control protocol.

Thanks for clarifying this.

Luckily Reaper with ReaLearn can do this with any MIDI input and without Mackie Control protocol.


By the way, since DAW is sending "channel select" via Mackie Control protocol via MIDI, is there any limit on the number of channels supported? In other words, I hope it is not implemented as a single 7-bit value. That would mean it could only reach 127 channels?

AtmanActive wrote: I hope it is not implemented as a single 7-bit value. That would mean it could only reach 127 channels?

It's worse than that, it's implemented as a 3-bit value. The Mackie Control protocol can only handle 8 channels at a time; to handle another set of 8 channels, you need to switch "bank". There is no limit to the number of banks, but all channels outside of the current bank of 8 channels are unknown to Mackie Control.

So if I understand correctly, a DAW sends a number from 0 to 7 and then we need to send Pitch Wheel message on a corresponding MIDI channel 0-7, for volume fader, for example.
I'm guessing DAW also sends the values for that channel so the program needs to remember that to be able to do step increments/decrements.

Well, kind of...

The majority of commands are Note On commands sent on channel 0. One of the few exceptions is the fader commands that are sent on channels 0-8 (channel 0-7 + master channel).

When channel 0 is selected, the daw sends a C1 Note On; when channel 1 is selected, the daw sends a C#1 Note On, and so on.

Commands are the same both ways; when you select channel 0 in your daw, it will send C1; to select channel 0 from your remote device, you should send C1.

Please check the top left document on this page, where all the command mappings are described. The channel numbering in that document is 1-based, i.e., the first midi channel is 1, not 0 (but on the protocol level, channel 0 should be used, which is a bit confusing).