Thanks for the question... the MONTAGE and MODX are truly Synthesizers and offer several ways to accomplish synthesis goals.

”Part LFO”
AWM2 and FM-X engine’s each have a Part LFO that be used to modulate parameters within a Part’s Insertion Effects. This can be applied with offsets on a per Oscillator basis within each of the synth engines. The Part LFO can be sync’d to the Tempo. The Part LFO has its uses (not appropriate for your request, however).

FM-X’s “2nd LFO”
The FM-X engine has a “2nd LFO” that is appropriate for Pitch, Amplitude and (now) Filter Modulation... as you may or may not remember, Classic DX FM did not have any Filters at all... heck it did not even have a clock to sync anything to... this 2nd LFO can be used with a controller like a MW to apply Depth control, however, you can make it full time by applying Depth directly instead of biasing it to a physical controller. No clock sync here; Consider it designed to be musical Modulation (adding vibrato during real-time play, for example... or for bringing in Tremolo, etc.

Programmable Tempo driven Control
The MONTAGE and MODX both feature what Yamaha refers to as the “Motion Control Synthesis Engine”... if you are ready (and your question indicates you are)... let’s discover “Motion Sequences”.

Designed for when you need to create Envelope or LFO-like control of a myriad of available parameters.
The Motion Sequencer can be used to control FM-X Pitch (at the Part parameter level) it can be used to control FM-X Operator Frequency at the individual Operator Level. You can assign it to Cutoff, to Resonance; You can assign it to any available Insert Effect parameter, to Part Volume, even individual Operator Level; Additionally, you can have it control the Speed, and the Depth of the PART LFO and the Speed and the Depth of the 2nd LFO, among the myriad of Destinations.

But applicable for your question the Motion Sequencer would be ideal for creating a Tempo referencing control of the parameters you say you need. Welcome to the 21st Century. Significantly, the Motion Sequencer can subdivide the tempo in any number of ways using the “Unit Multiply” and number of steps in your “Cycle”.
Briefly: Unit Multiply changes how the data references the current clock tempo... 100% = at the current tempo.
A “Cycle” can have from 1 to 16 steps.
The Motion Sequence has four Lanes - each represents a programmed movement

The default wave shape called “Standard” is a Sawtooth, tap “Reverse” to create a Sawtooth Down “Pulse”... you can shape this Pulse (even apply shape change to a real-time Knob).

Extra Credit: see this link
Mastering MODX: Motion Sequences

If you get stuck, post back here. We are not sure exactly what you are attempting to achieve, but don’t be afraid of this new feature... it is extremely powerful and designed for precisely the kind of thing you are describing. Let us know...

Alternative Methods
You can create or select an Arpeggio Phrase in the “Hybrid/Ctrl” Category. Arps automatically reference the tempo and among the 10,231 Arps the ‘control’ arps can be applied to your sound. Arp Type #10016 is “Filter 16” (basically a Control Arp is one that has no Notes, it’s strictly CC messages or PB messages... this one moves Filter Cutoff in 16th Notes pulses).
Set Arpeggio Key Mode = “Direct” this allows you to play the sound directly with the keys, while the Arp Phrase applies Filter movement. 16th Notes... by setting the Arp’s Unit Multiply to 200% you’ll get your eighth Notes.

These Control Arps were the germ idea that led to the Motion Sequencer. The Controller Arp do Cutoff (CC74), Express (CC11), Pan (CC10)... If you can describe or post a better idea of what you’re going for, we can help you find an appropriate Arp or show you how to create your own Control Arp. Let us know...

And again, thanks for question.

Thank you very much, BadMister! Really quick and detailed response!
I was fiddling around with the Motion Sequencer, used the OP Spectral, Cutoff and Resonance but I think I have to get deeper into it.
It's hard to describe the sound, I think it would be better to hear it.

Btw. I've seen many tutorials from you for Montage and previously the Motif XF. They're awesome! And really, you're one of the best presenters IMO.

Thank you very much, BadMister! Really quick and detailed response!
I was fiddling around with the Motion Sequencer, used the OP Spectral, Cutoff and Resonance but I think I have to get deeper into it.
It's hard to describe the sound, I think it would be better to hear it.

If you can post an audio recording of what you’re going after, perhaps some help setting up the Motion Sequencer will be possible.

What you are looking for may already exist as a Control Arp...

Thanks for the kind words...btw!

Hi Bad Mister,

I appreciate all of the information you've given us so far. Thank you.

I'm having an issue though. I still can't understand how to work around the 2nd LFO's lack of tempo sync. I'm using FM-X and am wanting to use an LFO sine wave to modulate the pitches of different operators within the same part. And I would like these modulations to be strictly in time to the music. Can you please tell me how to do this?

Thank you!

Nathan

I'm having an issue though. I still can't understand how to work around the 2nd LFO's lack of tempo sync. I'm using FM-X and am wanting to use an LFO sine wave to modulate the pitches of different operators within the same part. And I would like these modulations to be strictly in time to the music. Can you please tell me how to do this?

If I were to refer you to a thread, it would be this one...

From above... FM-X’s “2nd LFO”
The FM-X engine has a “2nd LFO” that is appropriate for Pitch, Amplitude and (now) Filter Modulation... as you may or may not remember, Classic DX FM did not have any Filters at all... heck it did not even have a clock to sync anything to... this 2nd LFO can be used with a controller like a MW to apply Depth control, however, you can make it full time by applying Depth directly instead of biasing it to a physical controller. No clock sync here; Consider it designed to be musical Modulation (adding vibrato during real-time play, for example... or for bringing in Tremolo, etc.

Therefore, the 2nd LFO is clearly not what you want to use if you are looking for it to be “strictly in time to the music”. That is not what the FM-X’s 2nd LFO is about. You want to begin to explore the Motion Sequencer. It can be viewed as a programmable parameter envelope or, because it can be looped and sync’d to tempo, it can be considered a programmable LFO.

You can create a controlled motion using the Motion Seq or use one of the Preset shapes, applying it to the parameters you desire to control will be a matter of utilizing the Control Assign matrix within the Part and Sync’ing the MSeq to Tempo. You can assign the MS Lane to vary Operator Frequency. Each Operator can be switched On/Off to follow this Motion, and each has its own Depth setting.

Start by selecting/creating your MS. I recommend working with one of the MS Presets - your basic shapes are represented - for example, select any of the “Triangle” Presets, using the dedicated MS “Shape” Knob, you can easily reshape it into a Sine Wave. You’ll need to determine at Key On do you want the Sine Wave to be at its apex (90 degrees) or at its zero cross point, or elsewhere. Are you changing the Frequency up from the start point, down from the start point? Do you want the pitch to go above and below the start point, etc., etc.

Bad Mister thank you for such a quick response!

I was making it more complicated than it needed to be. I was trying to use MS to sync the 2nd LFO.

Now I'm looking forward to playing with the MS more! Thank you again.

Holy Smokes MS is incredible!!