I'm going sort of by memory - but I think Effects 1 depth is Reverb Send and Effects 4 depth is Variation Send. If you look at the MIDI association descriptions for these - it may help you decode them then play around with the values to confirm your suspicions. I believe those EGs map to AEG.

https://www.midi.org/forms/midi_chart-v2.pdf
or
https://www.midi.org/specifications-old/item/table-3-control-change-messages-data-bytes-2

I could probably figure it out by experimenting, but why doesn’t Yamaha make the information available in a well-documented and coherent manner?

I could probably figure it out by experimenting, but why doesn’t Yamaha make the information available in a well-documented and coherent manner?

If we did, do you think anybody would actually read it? You didn’t.

Please see the “Synthesizer Parameter Manual” (pdf) Page 81-84, Item 3-2-4 Control Change. There you will find listed all the common Control Change messages that your MONTAGE will respond to from Control 0 through Control #101.

Just FYI. CC74 does not Control a specific Filter, it acts as an ‘offset’ to the currently active Filter(s), if any. In other words, if you created a MONTAGE PART and you left the Filter Type = Thru, CC74 would have no Filter Cutoff to Offset.

CC74 is what the dedicated front panel Knob labeled Cutoff sends. Again, no filter assigned to the Elements (AWM2) or Carrier(s) (FM-X)of the Part, CUTOFF will do nothing. It is an Offset to any active Filter’s Cutoff Frequency. It is not a Filter itself.

You will find the pdf “Synthesizer Parameter Manual” along side all the other PDF manuals for MONTAGE. Not great reading, but provided so when someone says “why doesn’t Yamaha make the information available in a well-documented and coherent manner?” We can say, “If we did, do you think anybody would actually read it?” Haha, just having some fun... enjoy!

Official MONTAGE Dowloads

Additionally, in the MONTAGE DATA LIST booklet, you’ll find item 3-1-3 Control Change (Page 187) which gets into what’s transmitted and what CCs are received. If significant changes are made (like a firmware update, please remember to get the latest documentation... a new Data List booklet was issued at version 2.50) But we expect no one to read the Data List booklets (too obvious)! Too much small print... storyline is slow.
:-)

If we did, do you think anybody would actually read it? You didn’t.

Point taken. I’m sorry about the tone of that comment. But, in my own defense, I had just spent a couple of hours trying to make sense of what was in the Data List PDF, couldn’t make any useful sense out of it, and was very frustrated.

And I really tried. That’s how I ended up looking at that material in the Data List PDF. I have used the Synthesizer Parameter Manual PDF a lot, but mainly for looking up different effects. I hadn’t noticed that section about MIDI, which is my bad. But you know, it wouldn’t have hurt for Yamaha to have put a line into that part of the Data List PDF that said, “For further information, see the Synthesizer Parameter Manual PDF“. (Or did I miss that too?) Believe me, I would have been right on top of that. I’m a software engineer. I believe in reading the manuals.

Anyway, thanks for the pointer to the right place in the documentation, and for the additional information about the offsets.

It turns out that a handy little chart I created in 2017 is very relevant to this discussion. There’s so much to know about the Montage in particular and MIDI/computer music in general that it’s just impossible for me to keep it all in my head at once.

https://www.yamahasynth.com/forum/slider-and-knob-midi-output

http://spot.pcc.edu/~mtrigobo/music/yamahasynth_files/montage_midi_output.jpg

I know you are piecing together the information about CC messages, what gets sent where and when.
In using an external MIDI Controller, using the MONTAGE as a Tone Generator, you will mostly be using standard function CC messages.

Sending a standard MIDI message like CC74 In via MIDI is the same as moving the dedicated CUTOFF Knob.... Offsets, you can opt in or out on a per Part basis.
However, you will discover using an Assign Knob, CC23, for example, allows you to go into the MONTAGE engine and decide to control a specific Filter’s Cutoff, with a specific range/direction/depth of change. You can, if you so desire, go in and define exactly how the controller behaves within the sound.

This is why when working with an external device like a ROLI you will want to analyze the sound you’re working with, then select the specific parameters you want to control. Use the eight Part Assign Knob cc numbers as a gateway to more specific, directed, defined control.

It will take experimentation. But try controlling Filter’s using the standard CC74.
Then set up a situation where you assign external control over a Part’s AsgnKnob, then assign that AsgnKnb to do things within the Element’s Filter. No longer do all the Filters in an AWM2 Part have to do the same thing, suddenly, you can address each very individually... not as important on your bread & butter sounds, but when getting deeper into synthy sounds, this is a gold mine.