There's not a great way for key value to be directly integrated as a "modulation control" source. You can use envelope follower to accomplish this, however. It's a "trick" I often use. The downside is having to "burn" a PART for this - but it does get the job done.

One thing you can control from the bottom to the top of the keyboard is volume. You can make bottom notes very quiet and top notes very loud - or vice-versa.

What you do is add a PART which you take the output and route it to OFF. This will be your envelope generator PART which will generate values from 0-127 for modulating your LFO(s). This PART should be setup so the volume of low keys vs. high keys "acts" like you want the LFO modulation to but using volume.

Then - with your sounding PART (the one with the LFO) - use Envelope Follower #n where #n is the PART number you have routed as OFF. It's OFF so you do not hear this PART.

For me, the best type of sound to use as the source of the envelope follower is an FM-X sine wave as it tends to be very stable volume-wise. I would setup the ADSR for the (output=OFF) envelope generator PART so there is no shape which would affect the volume. Also set it to monophonic so chords are not louder than single node. Also I tend to set the release to maximum to achieve infinite sustain so my envelope generator is always outputting the volume of the last key played - although this is a matter of preference how you want this to work. I use the gain and hysteresis on the envelope generator to get the most stable output and the best range. Another downside is that dynamic range may not be scaled all the way from 0-127 - but you can probably get something close then use the LFO parameters to fix to full-scale with some loss in granularity.

Eyal wrote:

Namely keytrack modulation for other parameters?

I can't find an option to modulate via Keytrack (very common with synths) - the key follow found Filter Cutoff envelope(also common practice where the cutoff is lower on the lower notes of the keyboard, higher on the higher notes of the keyboard or the opposite), but also in the Pitch Env and Amp Env.

I hoped to find keytrack as modulation source - I want to modulate LFO speed with keytrack. as possible on the SY85 or Alesis QS. Striking effect on pads.

The MONTAGE AWM2 engine differs quite a bit from the AWM2 engine in the SY85. The settings to change LFO Speed via a Keytrack parameter is not available in MONTAGE. However, in designing sounds you could take the approach using the MONTAGE’s ability to build your Waveform from eight Elements per Part (and then multiple Parts) which can be regioned either horizontally (across) the keyboard and/or vertically via velocity. If mapping your Elements across keys making different regions of notes, each region could easily be addressed in different ways... with their own LFO even.

In terms of new wrinkles for building Pad sounds:
In the most recently posted study of XF Performances, the Control Box with its 3 Destination matrix, you can adjust the Phase for the Depth (application) per Element. The experiment in the article takes you through creating movement using just three Elements... in building a MONTAGE Pad sound you can construct as many Elements, and create as many regions for those Elements across the Keyboard as you may need.

Don’t look at it as burning an additional Element or burning a Part, for that matter... think of it as having a big budget modular where you can add more components (more filters, more Elements, etc., etc.)... as you may require to construct the sound.

So while the Keytrack parameter for applying LFO is not directly available any longer, you’ll find some new possibilities for creating movement inside of Pad sounds... in the previous article study of XF Performances, we looked at creating movement within a Pad sound using the Motion Sequencer...

Each Element, each Part can be addressed on a *per* block basis, so a single gesture (say increasing the Super Knob) would adjust each according to how you design. The orchestral horn “swells” use this type of thing with Element Levels as the gesture of increasing the Super Knob brings in and fades out different Elements to create a dynamic change by smoothly morphing between Waveforms with differing harmonic content... This winds up being quite dramatically different from simply opening a filter to get more harmonic content, these “Swells” are more "organic" because you are morphing between samples that actually contain the exact harmonics of the orchestral horns at differing intensities. And it all is so smooth and controllable. Being able to scale the response of parameters to control gestures, I’m finding is one of MONTAGE’s strongest points... the more you edit the more you get this feeling. By addressing Elements in this fashion you should be able to do a similar thing horizontally... I’ll be on the look out for any existing examples...

Key Track in FM-X
Certainly on the FM-X side of the synth, don't forget the dual nature of the MONTAGE, the Key scaling of modulation across the Range is accomplished as a function of FM itself. Any Operator can be a Modulator and therefore a Low Frequency Oscillator, and any Operator can be key scaled across the Keyboard Range.

In general, building Pad sounds is a particular strength of FM-X...