Owning both Montage and FS1R I can say that the latter instrument can produce certain sounds that the former is, probably, not capable of.
I would Yamaha create a converter that allows Montage users import FS1R Performances, with the relevant limitations due to the absence of those unvoiced operators.

Not to pout too loudly -- but I can't really resist:

Given how much of FM-X started with the FS1R's capabilities - it's so disappointing (to me) that FM-X didn't transfer over all of the FS1R's capabilities over. Formant, unvoiced, etc. At least to be a super-set of FS1R. Despite the FS1R's sales bomb - it really does have a lot of nostalgia with the biggest gripe being in the programming interface. Something a touchscreen and proper UI has a lot of opportunity to fix. Still, I don't think they "should" have made this happen more than I see in almost all Yamaha gear a lot of legacy being left on the table. No doubt it would have taken more time to develop these features and proper interface which could have jeopardized the release. Introduction of the Fantom and the timing of that shows it was important for Montage (FM-X) to released when it did.

Those items that make the FS1R what it is just don't translate and what remains are sounds that already translate. I'm not sure how much value there would be in translating FS1R-centric patches over to FM-X. You can feel free to leave an FS1R sysex dump (if you have one) for a particular patch and I can translate what I can.

Beyond the FS1R, FM-X - or at least the Montage instantiation of it in particular - has the "butter" output stage and design that makes anything coming out of that instrument sound better than FS1R in terms of fidelity.

However, the capabilities are something I would certainly enjoy. There's also an interesting Casio "vocal" keyboard that has similar features although packaged differently and I think playing vocals rather than vocoder'ing them would have some values to me personally. Although certainly the FS1R demos of this type of stuff sounds dated - there are some modern "retro" songs that reproduce that kind of sound.

Either way - I'd love to have a modern interface around FS1R to see what new sounds people come up with.

BTW - apologies, in advance, for following a response that went tangent to the original question. Instead of answering what FM-X goodness I've experienced and following a response that brings up another keyboard entirely and lamenting what isn't there.

When I talk about the output stage of FM-X, I hint towards my general feeling that everything (including FM-X) sounds better with the latest generation due to attention to the output stage in the analog domain. This is not FM-X specific - but it is a component of the FM-X signal chain.

It's probably inevitable that this thread drifts to other FM sounds, precisely because there's so much unrealised potential (of FM approaches) within FM-X.

My initial thoughts for this thread were to ask about all FM sounds, because it fascinates me that some amazing stuff was done in the 90's with FM, and that seems to still be the high water mark. The best I've recently heard come from the Korg OpSix, which has transformed hardware FM by simplifying the user interface whilst expanding the "oscillators" by adding other wave shapes, such that it's much more musically pleasing with far less effort.

Similarly, there's something very warm about the Digitone from Elektron, that's (in my efforts) been impossible to recreate within FM-X.

There's something scratchy/cheap about FM-X that needs to be damped/reigned in by effects and/or exploited by reverb to make it less starkly brittle and sharp.

Despite never having owned or even touched the FS1R, youtube has quite a reservoir of interesting insights into its wonders, and the huge range of results that resulted from the passions it evoked within sound designers. It's transparently obvious why it attracted effort to extract the best from it.

Nothing like this sort of energy seems to have been sparked by the arrival of FM-X. Kind of a universal "meh" has seemingly been expelled by the world's sound designers, upon any significant research and experimentation with it, with the exception of folks paid to use, endorse and promote it.

In Manny's second set of Tutorials (FM Xpert) he creates an 8x FM-X Part "Grand Piano".

It's not that I am a fan of Grand Pianos, but it goes to show what FM-X can do in the right hands (the hands of a well educated FM Synthesis Doctor!).

It's not so much that FM-X is limited, more-so that access to FM programming knowledge is limited.

By contrast a 10 minute tutorial on Subtractive Synthesis is enough to get most users moving forward.

The FM-X learning curve is a lot steeper, and a lot longer.

OpSix is still FM, but by providing a lot more Operator waveforms, and physical editing controls, it offers more low hanging fruit.

In reality, I imagine most OpSix users are still limiting themselves to 2-Op stacks, the difference being the Carrier waveforms are "almost there" to begin with, and the Modulator is offering little more than fancy "movement of sound" options.

In the OpSix... 3, 4, 5 and 6 Operator stacks are still available options, but are as equally complex in design as FM-X, and therefore avoided by those seeking quick wins.

In FM theory, you don't actually need anything more than a Sine Wave Operator. However, increasing accuracy, does mean increasing the number of Operators, and therefore Algorithms.

So, I don't think owning an OpSix will make you a better FM Programmer, but will give you more basic sound options.

The Opsix takes FM in whole new directions. It's not just easier to use. It's an incredible increase in FM's capability in a relatively cheap and capable little unit. It is a deceptively deep and powerful tool and simply empowering, too. It is a masterstroke and will probably forever change expectations of FM synthesis, as nobody will (from now on) try to launch a new FM synth that can't beat it.

I'm not nearly as impressed as you are by Manny's piano sounds made with FM-X. I am impressed with the rigour of his tutorial design. Perhaps I've come to experience FM from a different perspective than you, and see what he did as a true tutorial, in that the objective was a known, so that the tutorial could teach FM to that target known, because that works for some, to recreate and learn that way, whilst I'm keen to see what FM can add to sound design.

FM, for the longest time, has been good at a sort of "modelling" of many traditional sounds. But it's also incredibly capable of new sounds, which are harder to corral such that they're new without being annoying, largely due to the limitations of the interactions between sine waves.

Again, that's the brilliance of the Opsix. It solved that signature squawk, and then went into zones of honey, silk and wine.

FM-X is a tricky beast because it's limited by ancient envelopes that exaggerate resonance in an unattractive manner and addicted to and hobbled by trying to stick to the legacy of Yamaha FM.