When it comes to FM synthesis (no hype) you are not going to find a more experienced company than Yamaha. Nor will you find an engine that comes close to doing as much as the FM-X engine in the current Yamaha synths.

FM-X on the MONTAGE/MODX work with one Mode, “Performance Mode”, all parameter settings made for an FM-X sound are integrated into the single playable mode. You can command as many as eight 8-Operator FM-X tone generators... (more than an entire TX816) in a single KBD CTRL Performance. Each of the eight modules (Parts) can have their own Ring Modulation, their own Wave Folder, their own Filter, their own routing to Effects, etc., etc., etc.

Each FM-X Part can be assigned one of the 18 different Filter Types
Ring Modulation and Wave Folder are terms MONTAGE/MODX users will find familiar and are easily assignable per Part, or globally.

Curious question, what do you really want to know? If MONTAGE will accept the “Pepsi challenge”... the answer is a resonating, Yes!
if you are wanting to find out about Korg synths, you are in the wrong place... like most companies they will have their own approach and their own parameters, modes, effects, etc., etc., etc.

If you have an FM-X specific question, this is the forum.

You have the Ring Modulation effect, but that isn't going to be the same as having it applied to each note. I'm not sure how useful ring mod actually is though.

The more interesting aspect of the Opsix to me are the user algorithms. At the same time though FM-X has 8 operators instead of 6, you can layer parts, and the MODX (and especially the MONTAGE) has the polyphony to back that layering up. To match the Opsix's best-case 32 note polyphony you can layer two parts on the MODX and four parts on the MONTAGE.

The Opsix, as the name implies, has 2 less operators than Montage's FM-X. That said, the Opsix, as a dedicated FM keyboard, has lots of "innovations" that differentiate it from Montage/MODX's FM-X.

Starting with the controls - sliders and knobs. The knobs and sliders will identify by changing their illumination color if an operator is a carrier or modulator. This more quickly presents the keyboardist with information if moving a slider is going to affect the mixing level (carrier) or timbre (operator) of the sound. The knobs are dedicated to change the ratio ("pitch" ) of each operator. This you can mimic on Montage since knobs are assignable - although they will not illuminate or identify which is the carrier vs. modulator.

There are other "GUI" differences. The Opsix generally tries to reduce the amount of menu diving to get to various parameters for display and edit. There are dedicated buttons to navigate through the FM architecture and the display makes attempts at facilitating the workflow. From a display perspective - I'm not sure which keyboard has an edge since Opsix has a smaller display surface and some compromises were made here. But from a button/navigation perspective - Opsix has more dedicated/labeled FM-centric buttons and knobs that give Opsix the edge here. This is understandable in a dedicated FM keyboard vs. a synth with FM as only one of its engines.

For the operator modes - starting with just standard FM in Opsix (the one that "matches" FM-X's implementation) - Opsix's FM mode adds phase control for all operators. This is not something available in FM-X. Although my manual diving of Opsix shows that not each operator has its own phase control as the diagrams imply. The manual seems to read that operator phase is a global value applied to all operators and can either be fixed (at 0, not modulated), completely random (all operators get a random phase and could/would be different from each other), or "free" - which is randomized phase but all operators are set to the same randomized phase.

A second difference in "standard" FM is Opsix's "wave width". This allows for you to take the waveform (such as the standard sine wave) and, for one period of the sine wave, define that the sine wave only takes up 50% or 25% of the period. The other 50% or 70% of the time, the waveform will output a center value.

FM-X doesn't have this. Korg claims this is advantageous to dance music. Unlike Korg's operator phase (which is shared) - the operator wave width is unique for every operator.

Also different in standard FM mode of the Opsix are the preset waveforms. FM-X has Sine and various other settings for the waveform (Allx2, Oddx2, Resonancex2) along with various parameters to shape the resulting waveform. There is a lot of flexibility with this approach although it's not very intuitive to arrive at desired results if you want a square, triangle, etc. Opsix has the standard sine wave and 20 other waveform types. Some are low-res (such as sin 12bit, sin 8bit) to better emulate vintage FM. Then there are simple-to-relate-to other waveforms like triangle, saw, square, s/h noise, and white noise. There are other waveform types which deal with adding specific harmonics (1st - 8th) to the fundamental or generating some harmonics of each basic shape (saw, triangle, square). The basic shapes of square and saw have an "HD" waveform which claims to produce a different sound by taking lots of CPU resources to generate "richer high-end overtones" than the standard square/saw waveforms. FM-X doesn't take this approach. You'll need to dial in various equivalent waveforms using the FM-X parameters given and some waveforms are not available at all on FM-X or cannot be duplicated. The basic shapes - yes. But noise, the additive waveforms (for the most part), and bit reduction - you'll have to find another way. Mainly using something other than operators - using LFO - motion sequence - effects - etc. to get to a similar destination. I personally prefer (and Yamaha has done this before with previous FM synths) giving a larger menu of preset waveforms such as provided by Opsix. That said - I do not believe the Opsix has FM-X's bases covered either. FM-X provides waveform types not available in Opsix as FM-X is less of a preset menu and more of a build-your-own. Although still this (FM-X) approach has some limitations.

For Opsix "ring mod" mode is not an effect as much as it is a reconfiguration of the operator's relationship with the next operator (carrier or another modulator). Although Montage's FM-X has a ring modulator effect, this is different from re-configuring the FM engine itself to something different such that the output of an operator stage no longer does standard FM. FM-X doesn't have this mode.

Similarly, "Filter FM" in Opsix doesn't look like something supported by FM-X. Again, this isn't an effect on top of FM - but a reconfiguration of how the operators themselves work together (like "ring mod" mode).

The other 2 modes seem similar to FM-X's approach. Opsix's "Filter" and "Wave Folder". Although I'd have to dig deeper to see if there is anything differentiating these two modes vs. FM-X's effects.

Speaking of effects - I can say that a quick scan through the Opsix's effects, I noticed "Shimmer" reverb. This is something that Montage users have requested - a "shimmer" effect. Opsix has this base covered while Montage (AWM2 or FM) does not. The closest I could come in Montage was using gymnasium and tweaking values.

Moving on ...

The Opsix has less preset algorithms than FM-X. However, Opsix allows for user algorithms. This really opens up lots of possibilities not available in FM-X. User algorithms allow for each modulator to apply feedback to itself. FM-X has fixed feedback only one operator which receives feedback. Opsix can assign every operator with self-feedback. This is more similar to the implementation in the Reface-DX with respect to feedback flexibility. Beyond that, user algorithms allow for you to assign the output of one operator to any other operator. There is assignable chaining (op n -> op n+1). And there is also arbitrary carrier assignment. Meaning that any of Opsix's 6 operators can be configured to produce audio output (i.e. carrier). Due to the flexibility, you can assign carriers as modulators for other operators. In this case - the control surface will show a blended color for operators that are both modulators and carriers. FM-X doesn't do any of this. This is more of a feature available in software FM engines such as FM8.

Thank you Jason!

It appeared, at first glance, that the OPSiX was a little special. You've confirmed that, and then some.

CHEERS

I have not played or heard this and would be wary of ‘reviews’ by anyone who has not either! Just saying.

Point of order: The MONTAGE, having an FM-X engine, can easily do Ring Modulation (any FM synth can create this, from the mini-key synth refaceDX, to the FM Essential app, to the mighty MONTAGE). Please see Dr. Manny Fernandez’ FM tutorials here on this site. What is really awesome is that the MONTAGE additionally has is two (count them 2) Ring Modulator effects types.

Ring Modulation (you can Google it... is where two sources (typically Sine waves) interact so you hear the sum and the difference frequency... this is a very basic function for any FM synth to accomplish... the programmer just needs to know what it is! Listen to the examples... any FM synth from the least to the best can do this!

When you tune your Operator to whole integer Ratio values, you get the familiar array of basic synthesizer waveforms (like sawtooth - which contains all harmonics; pulse - which contains just the odd numbered harmonics, square - which is a specific pulse wave with equal on/off periods)...from these basic wave shapes you conjure up strings, brass, electric pianos, synth leads, pads, etc., etc. However, when you start getting into Operator tunings that are not whole integer values, their interaction creates sidebands and you can get glorious bell tones... (non-whole integer multiples of the Fundamental).

FM is famous for its ability to recreate ringing bell tones and clangorous metallic sounds... put these in motion - you can do so by sweeping the Frequency or by simply increasing/decreasing the output of an Operator (Modulator) setup to bring in and out one of the frequencies involved in generating the sum/difference tones (‘motion’ is another primary feature of the FM-X engine) you can get extremely rich Ring Modulation tones... if you have played with the SmartMorph function on MONTAGE, even briefly... you can’t help but create these tones (even if you are not familiar with how to program FM).

The two boutique level Ring Modulator Effects found in the MONTAGE are in addition to the Ring Modulation function you can setup with simple FM Operator programming. The Effects allow you to apply ring modulation to on any sound... be it an AWM2 sample based sound, an FM-X sound, even a vocal... anything plugged into the analog input. The Dynamic Ring Modulator is Side Chain capable! This means you can route other Parts, synths, external inputs to interact.

To read this “review” it makes it to sound that the Ring Modulator Effects are some kind of negative — actually, we think you’ll discover they are absolutely brilliant and extremely easy to use... so quite the contrary.

The Ring Modulator and the Dynamic Ring Modulator (which can be modulated with your performing dynamics) are available right in your synth. I would say the “review” is at best interesting but not having actually played one or heard one I wouldn’t dare speculate about it (don’t know how anyone could really). But shame on not knowing the synth you own.

When you send a complex wave shape into a Modulator, like sending the output of a Carrier into a Modulator, the potential for it to go quickly into ‘noise’ is there.

Feedback per Operator in the MONTAGE was upgraded with Spectral Wave selection/Skirt and Resonance features. Every one of the 8 MONTAGE FM-X is capable of generating the complexity of self Feedback, and beyond... the standard, old-fashioned DX7 Feedback parameter is included in the new FM-X engine simply to allow compatibility with the legacy DX/TX sounds of the past!

Please, again, if you’re curious about FM Synthesis, spend some time with the plethora of articles and tutorials available on this site... the tutorials include examples allowing you to see, hear and learn how to use this synthesis. If you still think that the MONTAGE lacks the refaceDX’s ability to do per Operator Feedback, you owe it to yourself to spend a little time exploring.

Extra Credit
Featured this month on this site: LEARN: FM Synthesis Collection

Waveforms created with skirt vs feedback are not equivalent to feedback although skirt can be used to approximate.

The "ring modulation" sound has some overlap with FM in final result - but they're different approaches and the FM-X engine doesn't have the same arrangement.

If Korg's final result (ease of programming, performance-time controls and flexibility, sound variety, sound quality, selection/quality of effects, etc) are matching/better/worse relative to FM-X - I have no comment on. There are features that exist in Opsix that do not exist in Montage/MODX FM-X. I haven't commented on the quality of the implementation - only that there are checkboxes on both sides that make each implementation unique.

How one relates to Opsix and its features is a different matter.

The Opsix, as the name implies, has 2 less operators than Montage's FM-X. That said, the Opsix, as a dedicated FM keyboard, has lots of "innovations" that differentiate it from Montage/MODX's FM-X...

Thanks for providing details. As a music hobbyist,I like to tinker. I pay a price to explore and learn analog and digital synthesis, whether through vintage keyboards, emulators, or contemporary instruments. The words "comparison" or "versus" often show up in my web searches because I'm looking for precisely these differences and overlaps in capabilities. Which synth gives me the most features for my money? How close can I get to duplicating a classic sound, or how deep can I explore a technology? Did I make the right purchase?

For creating rich FM sounds, it seems like both instruments will get me there. However, it seems like the the Opsix might be more appropriate for learning, experimentation, and live improvisation, while the Montage/MODX is geared toward a more scripted performance. That being said, I still want one of each!!

I know nothing of the OpSix, but I second BMs comments regards Manny's tutorials, and Yamaha's "from the ground up" approach.

The FMX engine is plenty powerful, and Manny's tutorials will help you unlock its depths. Anything anyone might "want it to do" has been pre-empted by Manny, who clearly knows his stuff.

If you're new to FM, and still deciding, it might be worth getting a VST plug in first to cut your teeth on.

Could you please, oh, please, publish a book, or as many as required, so that we, the so much interested people, can finally understand what we do when moving sliders, turning knobs and pressing buttons...?

Contains such as...."When you tune your Operator to whole integer Ratio values, you get the familiar array of basic synthesizer waveforms (like sawtooth - which contains all harmonics; pulse - which contains just the odd numbered harmonics, square - which is a specific pulse wave with equal on/off periods)...from these basic wave shapes you conjure up strings, brass, electric pianos, synth leads, pads, etc., etc. " should be the very starting point.

Or I think perhaps it could just be included as an addendum to the operating manual...or as a separate item for the interested buyer.

I have no words...thank you, thank you very much for your good teaching.

First buyer for your next Montage substitute, Yamaha.

Could you please, oh, please, publish a book, or as many as required, so that we, the so much interested people, can finally understand what we do when moving sliders, turning knobs and pressing buttons...?

I hoped for the same thing. Somebody from a different forum sent me a .pdf document... an "A-Z" of FM Synthesis... it was a University Thesis, intended as a beginner to expert guide. You're head would explode after about Page 6. And there were around 200 A4 pages of small font to get through.

Imagine someone deciding to make a Cook Book of every recipe concocted of any and every ingredient known to man. It would become the proverbial Sisyphean Task.

If someone wrote such a book, and you were one of a few who decided to "buy the book" and read it, you would struggle to digest it... it is all numbers and formulas. It's like trying to eat a box of crackers without water to wash it down.

The best (the only?) way is to get your hands and ears on an FM Instrument and start working through tutorials. Repetitive, cognitive, practical learning.

Could you please, oh, please, publish a book, or as many as required, so that we, the so much interested people, can finally understand what we do when moving sliders, turning knobs and pressing buttons...?

Bad Mister gave a link above ""LEARN:FM Synthesis Collection"LEARN:FM Synthesis Collection"
You will find several links.

Peter, from Easysound, wrote the "Montage FM-Xguide" Part 1-4 : Montage FM-X Guide Part 1

Thank you, Antony.

I know you can go so deep that a whole Degree would be required. Guess many attending our questions have probably accomplished three, to say the least.

But I am talking about the first layers.

Once you know what a given selection among the many option does mean, apart from the appropriate given name, it gives you way to carry onto another layer...and so on and on.
You can surely stop reading whenever and wherever feel fully satisfied.

Also, and not less important, one feels more human and less monkey.
I remember the first time I played piano, without any knowledge...Later, reading about octaves and chords made me very happy: I myself had firstly discovered the well sounding octaves and some of the very basic chords...Even the scales showing much sadness, lots of happiness and those more neutral !!!! Then came tuning, harmony, orchestration...

The funny thing about it is that what you accomplish is or can be related to some recognized knowledge with deep foundations, not the result of casualty, and that feels very well to my mind. So having the chance to be told what SAW
or PULSE... or whatever, means would be great.

Exactly as choosing between two boxes. Apple and orange. I would like them open and showing their respective content before starting the search for a banana...

@Fernando...

A question to ponder...

Where does "basic" FM stop, and where does "advanced" FM begin? How would you draw that boundary on an FM Map?

Jason makes a relevant observation above regards Yamaha FM-X vs Korg Advanced FM. FM-X can do things AFM can't and vice versa. So which is best depends on what you want to achieve. And knowing what you want to achieve, will require at least some level of experience using any particular brand of FM and feeling out its perceived limits.

Assuming a "General FM Basics" book fell into your lap, and you read it, and understood it. Chances are, even with this knowledge, you would quickly run into confusing difficulties with the FM-X operating system, and I dare say the same for Korg.

In general FM, the most basic structure is a 2 Operator "Stacked" algorithm. 1st Operator (on the bottom) is the Carrier (the waveform you can hear). 2nd Operator (on the top) is the Modulator (the waveform you can't hear).

The Modulator waveform is used to "Frequency Modulate"** the Carrier waveform. This modulation affects the timbre of the output sound... it changes the sidebands aka harmonics.

So the net (basic) result is dependent on:-

1, The Carrier Waveform shape
2, The Modulator Waveform shape
3, The Frequency of the Modulator relative to the Carrier (Ratio)
4, The amplitude of the Modulator relative to the Carrier (Index)

In old style DX7 FM... all waveforms were sine waves.

In FM-X you get more choice of basic waveforms (a head start). Loosely .... Sine, Saw1, Saw2, Square 1, Square 2, Resonant 1, Resonant 2.

So, a basic 2 Operator FM-X Stack, can quickly tilt into "advanced" old school DX7 style FM (arguably advanced FM-X also).

There are a bunch tutorials/articles on the yamahasynth "Learn" page. I know that Manny's 1st article/tutorial in FM-Xplorations, dives into these "basic" 2 operator stacks, and explains how to get all your classic Saw, Triangle, Square and Pulse waves, and with some further reading (article 2, 3 etc) other classic Analogue Synth sounds such as Noise, Pulse Width Modulation and Oscillator Sync.

There are more great tutorials available also, including a set written by Bad Mister. FM 101 is another.

These are excellent "spoon feeding" tutorials that explain everything as you move through them. They include downloadable exercises (real performance files you can load into your MODX/MONTAGE), with YouTube and Soundcloud demos to keep you on track.

I tried the 200 Page FM Book. It was excruciatingly painful.

I much preferred the tutorials. That's also what I was advised to do.

** Re: Frequency Modulate... sounds like I am stating the obvious. But in truth, it is not as obvious as it sounds (don't try to simplify it in terms of LFOs and Pitch Modulation/Vibrato). Once the frequency of the Modulator is in the audible or higher ranges all kinds of complex mathematical interactions take place. The audible results of which we know as FM Synthesis.

Some trivia.. you've heard of FM Radio. The Carrier in this case is a MegaHertz simple sine wave (Radio Frequency). The Modulator waveform is the radio station (DJ, songs etc). Your home radio tunes into (hears) the carrier (channel) and de-modulates the signal (it filters out the sine wave, and extracts the sidebands i.e. the modulator signal) and you are left with your favourite radio station. 🙂

Thank you, again...

But..." And knowing what you want to achieve, will require at least some level of experience using any particular brand of FM and feeling out its perceived limits."

True, but I can stand in front of an old biplane telling everyone I want to reach the Moon...
At times, it is best to be told what you have at your disposal. You have a biplane there is clearly not enough. You have a biplane there that climbs up to 15000 feet is a step further. That's it...