Mastering MODX: An FM-X Exploration, Part IV

Mastering MODX: An FM-X Exploration, Part IV This article references content saved in MODX Connect, the VST/AU and standalone software component for capturing and recalling MODX Performances: Get MODX Connect for Mac or PC here. Get the file for this article (Moving Floor ex.X8B) here. In an effort to show how to go about building […]

Mastering MODX: An FM-X Exploration, Part IV

This article references content saved in MODX Connect, the VST/AU and standalone software component for capturing and recalling MODX Performances:

In an effort to show how to go about building basic wave shapes using FM-X parameters, we’ve looked at four different, simple 2-Operator FM-X Single Part Performances – each using just a simple Modulator:Carrier stack. Now let’s move on with a look at a Multi-Part Performance. Please find the zipped download example at the end of this article:


This is a specially edited version of the Factory Preset Performance: Moving Floor.

Exploring FM-X “Moving Floor(ex)”

Please download this edited version at the very bottom of this article – it is provided in a “MODX Connect” Bulk file, .X8B. It’s been edited so that the different Assign Knob functions have been identified per Part and for the Super Knob’s Assign Knobs. This program is made up our four very simple FM-X components, and as we’ve seen in our previous installments, by looking at each of the FM-X component individually, it leaves plenty of room to build. The “Motion” here is provided by the Arpeggiators; and “Motion Control” is involved in the selected Part parameters that are linked to the Super Knob.

The FM-X Parts 1, 2, 3 and 4 are those that we have studied over the past few weeks, so they should sound familiar and their behavior will be familiar now. While many people think you need all 8 Operators to create intense complex tones, we’ve seen that it all begins with just a simple two Operator stack; the basic M:C (Modulator:Carrier) interaction, and we’ve learned that because each Operator can begin as a more complex Wave than the traditional (FM) Sine Wave, you can vary the timbre, shaping the harmonic content in ever more interesting ways. In keeping with our learning to swim analogy: we have waded out with our snorkel gear, and peeked under the surface at some very basic relationships. In future articles, here on YamahaSynth, we will get out the Scuba gear and go even deeper. The key thing to take away from this is: *exploring* is one of the best ways to learn. We have revealed some of the basic fundamentals of FM synthesis. We’ve done so avoiding the heavy math (we never even mentioned Bessel functions, not once) to show that you can accomplish a lot without it. Don’t over think or over analyze, use your ears first – then seek out the reason why it behaves as it does.

Keep in mind the Modulator (like the vibrato added by the violinist’s left hand) is not audible by itself; its influence is manifest as a change in the Carrier (the violin string in motion). It is the Carrier that is audible. It is the Modulator that affects the tone.

The “Recipe” or Algorithm: This Performance is made up of the four FM-X Parts, 1-4, plus a single Element AWM2 pad (Part 5 “Dance Pad”) and an AWM2 Drum Kit (Part 6 “Dancefloor Kit). You can mute this rhythmic Part or replace it with any percussion of your choosing. If you’ve experimented with Blake’s “MODX Connect Arpeggio 101” experiment, you can use the Drum Arp you created for that tutorial. Mostly we will be concentrating on the Assign Knobs and their interaction with each of the Parts we’ve studied.

Play through this Performance while on the basic [PERFORMANCE (HOME)] screen, shown below, where you can view all Parts, the Knobs and the Part’s activity meter. Move through the eight Scenes (red buttons). You will see that not all Parts are in each Scene, and the Super Knob causes sonic changes in the tone:

A SCENE can, among other things, remember which ARP SELECT number, 1-8, is playing. And while SCENE memories can also remember MUTE status – we are not using that here. When a PART is not active via an ARPEGGIO it is because it has been instructed to “rest” (yes, the musical term). More on that in moment, as well. Even if this type of “One Finger Performance” is not your cup of tea, the ARPs here make it very easy for us to explore and learn about what is happening in the FM-X engine. Because the ARP is “playing” the phrases, we can concentrate our attention on designing the sound – which is fun!

The Modulation Wheel (MW) is responsible for fading in the AWM2 Pad from Part 5. Unless the MW is advanced a bit, this Pad Part remains hidden. The Volume of the pad in Part 5 is biased to the position of the MW.

We often get a question because you can see above that the Fader for the Dance Pad in PART 5 is set at 0. This is because it is not in charge of changing the Volume of this PART, Volume has been re-assigned, so the position of the MW is in charge of its Output level. If you wish to remove this assignment, you can DELETE the CONTROL BOX (Source/Destination) assignment. More on this later. For now, realize that it is a programmer’s choice as to where Volume is controlled. Here they opted to use the MW as a “mix amount” control for the Pad – add to taste.

Let’s explore PART 5:

  • Touch [PART 5] to select it
  • Press [EDIT]
  • Touch “Mod/Control” > “Control Assign”
  • With the AUTO SELECT box active (green) move the MOD WHEEL to recall the screenshot shown below.

The MW is actually responsible for Volume, Cutoff, and Resonance.
[SOLO] PART 5 and move the MW to see/hear this:

To Solo a PART: Press the [PART SELECT – MUTE/SOLO] button.

Touch “Solo” > Touch the Part Number “5”.
Touch “X” or press [EXIT] to put the pop-up display away.

The assignment of both FILTER “Cutoff” and “Resonance” to the same SOURCE (controller) allows a single gesture to simultaneously open the Filter (raise the Cutoff Frequency) and decrease the Resonance so that the sound doesn’t “run-away” and go crazy, howling at the moon (remember “resonance” is that spike at one particular frequency making it louder than all others that can send harmonics flying off into the stratosphere); all this while increasing the volume of the PART. You can hear this by holding a chord as you slowly raise the MW. Hear how it is not just a linear sweep, it is multi-dimensional. You can see in the graphic above (Curve Type) how Cutoff is increasing as the MW is advanced. It begins to increase at about 1/3 of the way. But there is more going on….

Part 5 is single Element AWM2 PART – in keeping with the very minimalist construction. In the graphic below, we’ve highlighted the Resonance Control Box (Destination 3) to show how Resonance changes when the MW is advanced. At about half way, the Resonance is reduced:

The MW is responsible for moving three parameters simultaneously. When you highlight the VOLUME parameter (Destination 1, shown below) you will see that it immediately increases as the wheel is moved – the  weights this Curve so that the change in volume occurs early in the movement of the MW… while the movement of the Cutoff Frequency and Resonance is delayed a bit. This, as we’ve seen, is how the Control Box for each assignment allows you to shape the application of change. It does not have to be a linear movement, it can be customized to a dizzying degree, and shaped as you desire:

On an analog synth, opening the filter, reducing the resonance while increasing volume could take two hands, and possibly, a foot Control pedal. I say this not to imply that this is better, but just to point out certain moves you may be used to making on an analog synth’s front panel with multiple knobs, instead can be accomplished here, ‘ganged’ to a single gesture on a single control – allowing massive changes while you are occupied playing the keys. After all, the role this pad sound plays in this Performance is like the background chordal movement. It is not the “featured sound,” it is simply the sonic harmonic glue holding the patch together.

As you slowly change the Volume/Cutoff/Resonance by advancing the MW you can hear an interesting movement – in an AWM2 PART, each Element has its own Filter and Filter settings. To view this Element’s FILTER, from the screen shown above:

  • Touch “Elem1” along the bottom of the screen while in PART EDIT.
  • Touch “Filter” > “Type”:

When reading the FILTER diagram, you are looking at Frequency from low-to-high as you move left-to-right on the graphic. The shaded area of this Dual Low Pass Filter is the relative loudness of the frequencies the filter is allowing to Pass. The dip in the middle there can be heard – if you listen closely enough as you slowly sweep the MW. This particular PART is just a single Element, but each Element in a Normal AWM2 Part can have its own Filter, with its own unique Filter settings and movement in response to controller movement.

In future Explorations, we’ll see how FM-X sounds can be routed through one of the 18 Filter Types of MODX.

Extra Credit: Move MOD WHEEL parameters with FC1

For those of you with two FC7 pedals, you can opt to assign FC1 to become your Mod Wheel – allowing you to control this movement with your foot while keeping both hands on the keys.
This is done by navigating to the “COMMON/Audio” > “Control” > “Control Number” screen and setting Foot Ctrl 1 = 1:


[SOLO] let’s you listen to just the ONE selected Part; Manipulating several of the MUTE buttons you can chose to listen to any combination of Parts. Therefore, to listen to multiple Parts in combination, you would use the [MUTE] function.

Once you’ve selected a Part, you have, in effect, entered that Part and you’ve “opened” it for exploration. You will notice that you can switch the role of the FADERS from PART VOLUME to OUTPUT LEVEL for the ELEMENT (if AWM2) or OPERATOR (if FM-X) of the currently Selected PART using the left front panel button [PART – ELEMENT/OPERATOR].

If you then press [EDIT] – you enter Edit mode on the *selected* PART – you can then “Mute” and/or “Solo” the individual Operators or Elements (within this Part) using the touch screen option in the lower right corner of the Element screen:

  • If FM-X is involved, please remember, you cannot hear a Modulator directly, you can only hear the influence the Modulator has on the Carrier it is attached to in the Algorithm… therefore, Solo’ing a Modulator alone will result in silence (vibrato without the violin string = silence).
  • If AWM2 is involved you will be able to hear when that Element is active if it meets the required parameters as outline within the PART (key range, velocity range, etc).


For this experiment set the MW at minimum (Heel down if using FC1 as MW). If you do so, you will hear just the following PARTs as stored in the Scenes: While holding a Chord or note on the keyboard advance through the 8 SCENES (1-4, 5-8 red buttons) allowing each to play for several measures:

  • Scene 1: Part 4, 6
  • Scene 2: Parts 3, 4, 6
  • Scene 3: Parts 3, 4, 6
  • Scene 4: Parts 2, 3, 4, 6
  • Scene 5: Parts 1, 2, 3, 6
  • Scene 6: Parts 1, 2
  • Scene 7: Parts 1, 2, 3, 4, 6
  • Scene 8: Parts 3, 4, 6

And again, you can bring in PART 5 at any time by advancing the MW (or FC1).

ARPEGGIO NAVIGATION: Let’s take a look at the ARPEGGIO ASSIGNMENTS. We want to call to your attention two different views of the ARPEGGIO data.
In the first view, shown below, you are seeing an overview of all the active PARTS (you can view either 1-8 or 9-16) and the assignment of the ARPEGGIO Phrases for each of the 8 ARP SELECT locations. This view is helpful, when multiple PARTS are following Arps. You are viewing what is happening right now for the currently selected Arp, 1-8, ARP SELECT #1 is active in the screenshot:

Touch “Motion Control” > “Arpeggio”:

Here you are looking at PARTs 1-8. You see that PARTS 1, 2, 3, 4 and 6 will at some point, be responding to an arpeggio phrase. Currently ARP SELECT #1 is active (bottom of the screen). Notice that PARTs 1, 2 and 3 are assigned to play an ARP named “Mute 4/4” — this is equivalent to placing a musical REST in this location. It allows the PART to stay ‘armed’ and in synchronization with the clock – it will just be silent – like a musician reading rests on a page – they don’t play, they simply count the time. This is quite different from “OFF”. And that is the takeaway here. “OFF” means you would have to re-arm and then re-trigger a key to restart the PART arpeggiating. If you use a MUTE ARP phrase Type, then the PART will simply come in automatically at the top of the next measure, if an Arp phrase is posted in the next SCENE. This screen view shows us what each of the PARTs is doing for ARP SELECT 1. The MUTE Type arpeggio phrase is used instead of the regular PART MUTE button.

Notice: Arps can be set to change at the “top” of the next measure… making them musically intelligent. When you press a SELECT button to change SCENEs, the Arp phrase does not change immediately – you can choose to have the ARP wait until the top of the next measure.

But what if we want to view just the ARP Phrases assigned to the PART 4, individually, for example. There is a Part view of the Arpeggio assignment:

  • Select PART 4.
  • Press [EDIT].
  • You want to see in blue “Part 4 – Common” in the lower left of the screen.
  • Touch “Arpeggio” > “Individual”:
Here you are looking at the PART 4 Arp Phrase assignment across the eight ARP SELECTIONs.

For now, recognize these two different views. As they will come in handy when you are making and assigning your own Arpeggio Phrases. The take away here is that for convenience you have these two views. The overall view (all Parts) and the individual Part view. Each PART will have its own set of assigned phrases.


PART 4 is active.
For this experiment, select SCENE 1. Select PART 4.
Doing so will show you the PART 4 Assign Knobs in the screen:


As you move the SUPER KNOB (or advance the FC7 pedal assigned to Super Knob), you will observe that Part 4’s Assign Knobs 1, 6 and 7 are linked to its movement. PART 4’s Assign Knob 1 moves the distance 0~127, PART 4’s Assign Knob 6 moves from its stored value 64~127, while Assign Knob 7 advances from its stored value 50~127:

  • Assign Knob 1 is doing “Operator Frequency” (Modulator).
  • Assign Knob 6 is changing “EG Level” (Modulator).
  • Assign Knob 7 is changing “OP1 Decay” (Modulator).

You should recognize this as “P4” in our FM-X Explorations “Part 1” article: the range settings for each of the PARTS is being determined by the Motion Control > Super Knob VALUE 1 and 2 settings. These determine just how much change is applied. The assignments to the Super Knob’s Assign Knobs, takes place here:

  • Press [EDIT]
  • Touch “Common” > “X” to put the pop-in menu away
  • Touch “Control” > “Control Assign”

There are 8 Assignment Destinations in this Performance, four are shown per PAGE, tap “PAGE” and advance to PAGE 2.
The “Display Name” box is where you can assign a nickname for the SOURCE function – tap that box to create a Name. Selecting a good name can be tricky when you have more than one thing assigned to a particular controller or Knob. But you do not have to use any official title, you can call it “Purple” if that helps you remember what you’ve designated a particular controller to do. Below, it is called “P4_Freq” because it is only assigned to do Part 4’s Modulator Op Frequency. This reminds me what this Knob is going to do and to which PART it is going to do it. You can touch the “Destination to Name” box to use the default Destination name and assign it to the “Display Name”:

We should expect to see among the assignments the following concerning Part 4: ”Part 4 Assign 1”; “Part 4 Assign 6”; “Part 4 Assign 7” linked to Knobs on the upper Common/Audio level that move 0-127, 64-127 and 50-127, respectively.

In the screenshot above DESTINATION 6, “Part 4 Assign 1” is linked to the Super Knob’s “Assign Knob 6” as its SOURCE.
If you highlight “Part 4 Assign 6” you will see it is linked to the Super Knob’s “Assign Knob 7” as its SOURCE.
And if you highlight “Part 4 Assign 7” you will see it is linked to the Super Knob’s “Assign Knob 8” as its SOURCE.

From this we now know that on the Super Knob level of editing: Knobs 6, 7 and 8 will move 0-127, 64-127 and 50-127, respectively.
Return to the [HOME] screen, you will see the “Common Assign 1-4” as the active Knobs in the screen.
Press [ASSIGN] (flashes) to switch the active Knob to “Common Assign 5-8”.

You can see that Knobs 6, 7 and 8 are being applied to PART 4. The Display Name appears for KNOBS: Knob 6 (“P4_Freq”), Knob 7 (“P4_Mod”), and Knob 8 (“P4_Decay”). You can directly move these Knobs to affect change on PART 4. Try it:


PARTs 3 and 4 are active, along with the Drums.
SOLO PART 3 and SELECT it. View PART 3 Assign Knobs in the screen. As you move the SUPER KNOB, you will observe that only Part 3’s Assign Knob 4 (Resonance) is linked to the movement. You will recognize this as “P3” from our second article in this series.

Use the MUTE function to isolate just PART’s 3 and 4.

You can hear how PART 3 is mostly in your left speaker with some content that sneaks over to the right channel, and PART 4 is mostly in your right speaker with some content that sneaks over to the left channel. This is accomplished though PART Pan parameters (Part 3 is panned “L32”; Part 4 is panned ”R32”). The bits that sneak over to the opposite channel do so because the ”Alternate Pan” and ”Random Pan” parameters on the PART ‘x’ > “Part Settings” > “General” screen – shown below for PART 3 and PART 4, respectively:




Same as SCENE 2 except the Drums have added a Snare sound layered with the Kick drum.


PARTs 2, 3 and 4 are active along with the Drums.
PART 2 has joined PARTs 3 and 4, bringing in a counter-rhythm. You should recognize this as “P2” from the previous article.
SOLO Part 2
Part 2 has two parameters linked to the Super Knobs: Operator Frequency (Knob 1: 0-127) and EG Level (Knob 6: 80-127)

When you return to the COMMON ASSIGN view, you can see the two linked parameters listed as “P2_Freq” (Common Assign Knob 3) and “P2_Mod” (Common Assign Knob 4) – giving you direct access when on the HOME screen.


PARTs 1, 2, 3 and 6 are active. PART 1, which is a bookend to PART 2, joins in and replaces PART 4. PART 1 is duplicating the Arp phrase of PART 2. PART 1 (“P1”) has the same two parameters linked to the Super Knobs. Again, it is Operator Frequency and EG Level, but moving through a different range for “EG LEVEL”. “Operator Frequency” (Knob 1: 0-127) but “EG LEVEL” (Knob 6: 87-127) – creating a bit of dissonant ring.

When you return to the COMMON ASSIGN view, you can see the two linked parameter listed as “P1_Freq” (Common Assign Knob 1) and “P1_Mod” (Common Assign Knob 2) – giving you direct access when on the HOME screen.


PARTs 1 and 2 are active; all other Arps are resting (MUTE 4/4). You can play chords with your right hand and fade in the Pad (PART 5) by slowly raising the MW.


PARTs 1 and 2 continue with the same phrase, but are joined by all the others; 3, 4 and 6, slowly fade out the Pad (PART 5).


PARTs 3 and 4 continue, while PARTs 1 and 2 go to MUTE 4/4; a hihat joins the Kick drum in PART 6.

The individual Assign Knobs can be moved directly, whenever you desire. We have brought the Super Knob linked parameters and show their “DISPLAY NAME” so you have access to them. Because moving the Super Knob (at any time) will cause all those parameters linked to it to change together, while accessing a COMMON ASSIGN Knob directly gives you individual unique control.

Summary and Final Thoughts

How you go about editing and approaching any MODX Performance is a personal thing. Hopefully some of the instructions here will tweak your imagination to go in directions of your own. Do not feel the need to over analyze everything. We picked out a few things that make a point about how things are designed to work. It becomes very easy to disappoint yourself when learning through this exploration and discovery method. When you first learn to drive a car, it is very easy to make the complaint that “how come the car can’t fly?” You get so used to getting from place to place faster than you could walk or ride your bicycle – but don’t jump to conclusions that it will take you to the moon. For its purpose, the car moving as it does, will suffice. That said, we probably never would have flown to the moon if someone hadn’t thought ‘wouldn’t it be cool if…’ but that is product design, not SOUND DESIGN. The purpose here was to learn to use the Crayons in this box, to create your picture – not to design a different product. (Although it’s fun to imagine the future…)

Just because you can link something to be offset by the Super Knob or an Assignable Knob, please do not expect that every parameter you are offsetting will animate to show how that parameter value is changing – it is enough to program the response “by ear” and hear the change. While it might be helpful to actually see how the envelopes change, for example, but it is totally NOT necessary.

If you assign the PB Wheel to change the Pitch – the parameter setting does not show you HOW FAR you’ve bent the pitch. Not because you couldn’t have the instrument do that, but simply because it is quite unnecessary (music is for the ears, not the eyes) – this is something that the musician does “by ear”. You do not need to see the confirmation of how the Pitch parameters changed on the screen. Offsetting an Envelope Generator, or the Pitch of a sound, is better analyzed as a musician (not as a technician) – the whole purpose of this series was to show that “by ear” or by listening, you can begin to learn how to edit and program FM-X.

If you are going to over analyze anything, do so trying to figure out what the original programmer was attempting to do with each assignment. Then decide what you would like to do with the assignment. The parameters that you do see animate to physical controllers are those that are directly assigned (as opposed to being OFFSETS). For example, when you move the Element Level, or Part Volume parameters, directly.

Once you begin to see the scope of what is happening here, such a request would require (perhaps) just a little too much CPU power. We have been looking at a PERFORMANCE that uses only a small portion of the processing power of the MODX. We have left 48 Operators doing absolutely nothing. We have used an AWM2 (Pad) PART that leaves 7 of its Elements doing absolutely nothing. And from the Drum Kit with 73 Elements, we are using approximately a half dozen different sounds (kick, snare, hihat, etc). When you start to realize the size of the controller matrix you are actually dealing with, you begin to appreciate what is going on.

This Performance (Moving Floor) is a ‘snorkeler’s delight’, because of its simplicity. When there is actually a lot going on, you may begin to scratch your head about what is doing what to what. Please come back for future Exploration tutorials. It is important to experiment and to learn to navigate to the various areas of the MODX architecture. Getting used to Performance Control and PART selection, and then Part parameter controls.

FM-X Final Notes: This particular Performance had a very unique selection of knob assigned parameters. Each FM-X sound is likely to be entirely different in layout and assignments. The idea is when finding a sound you enjoy playing, lose the fear, dive in and explore what is assigned to do what. We basically had one thing assigned per knob, with one or two exceptions. When going deeper you will discover that multiple items can easily be assigned to a single Controller each with customized results, there is no one-way to accomplish a goal.

Enjoy Mastering MODX!

Need to catch up/revisit the earlier lessons? Find them here:


Want to discuss this article or series? Join the conversation on the Forum here.

And keep your eyes – and ears – open for more on mastering your MODX soon!

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