Montage allows converting DX7 (and other) SysEx files to Montage's format using an online tool.

On paper, Reface DX is a subset of Montage's FM synth - so there are no additional capabilities in Reface DX vs Montage. However, the format of Reface DX's SysEx is not compatible with the other 4-op FM synths and also not compatible with the DX7 6-op synth. Someone has been working on a converter for Reface DX to get DX7 (and other Montage compatible patches) to work with Reface.

There's an opportunity for Yamaha to add Montage into the Soundmondo fold and do some converting within the site. At least to get from Reface DX to Montage. However, even a Montage-to-Montage version of Soundmondo is not yet available.

If someone would write down all the parameters of a Reface DX for a given patch - you could enter that into Montage. Not aware of anything more automated at the moment.

Thanks for the reply, i should have been more specific when i asked because what i am wondering is the Reface DX's ability to apply feedback positively and negatively on each operator does not seem possible on the Montage. Unless i just have overlooked the feedback parameter for each operator the architecture seems slightly different.

Soundmondo support for Montage would be awesome indeed, lets keep our fingers crossed!

Interesting, I haven't really dug into the Reface FM implementation. Montage has a different method of achieving a square wave and supports feedback level of 0-7 as legacy FM synths do.

Source: https://yamahasynth.com/resources/basics-of-fm-synthesis/598-basics-of-fm-synthesis

Reface DX has a new implementation of Feedback that allows for the creation of either all the even and odd harmonic overtone series of a sawtooth wave with positive Feedback values or just the odd harmonic overtone series of a square wave with negative feedback settings.

I would imagine in reface the sign bit just sets the waveform (0 as sine, negative for square, positive for sawtooth) and absolute value is the level of feedback from 1 to 127. Also reface allows all operators to have their own individual feedback level. Montage keeps the DX7/FS1R type feedback where this is a global setting (not per operator) from 0 to 7.

To approximate this on Montage (at least single operator waveform selection) requires using the spectral form - "All" for sawtooth, "Odd" for square. Values of feedback, per operator, 1-127 - I guess you would use "Spectral Skirt" from 0-7.

So maybe:

Reface Positive Feedback (RfcFdbk=1 through 127) = Montage "All 1" Spectral Form, Spectral Skirt = Round(RfcFdbk/18)
Reface Negative Feedback (RfcFdbk = -1 through -127) = Montage "Odd 1" Spectral Form, Spectral Skirt = Round(Absolute(RfcFdbk)/18))

Thanks for the input Jason, that got me really close and with ALG 30 on Montage you can put feedback on 3 operators. The reface dx is much easier to make a saw wav on. (i have both). looking at the oscilloscope the Reface has the saw wav almost exactly. If you find a better way let me know.

There may be a better way - I'm by no means an FM expert. The Reface vs. Montage in this department are different beasts as the Montage is favoring compatibility with legacy hardware while Reface looks to be aiming more for specific results and economy of controls. Even though I've seen pushback from Yamaha on this point - I do think it's a "ding" that Montage didn't implement a number of waveforms in addition to the spectral forms. Like some other past Yamaha synths with Sine, Absolute value Sine, Double Freq Sine (1 wave, so 2nd wave is null), square, Single Freq 1/2 Sine (2nd half as null), Two "Shark fins" (1/4 Sin, all positive), Double Freq absolute (2nd half as null), and Sawtooth. This is what the OPL3 offers - basically used as an FM synth in soundcards. Other synths (with keys) from Yamaha have a number of "starter" waveforms and that idea has been extended by some non-Yamaha gear which I think does serve to allow for an economy of operators and overall programming tweaking.

The Reface has a scaled-down version of this approach offering 3 "starter" waveforms.

If the shape of the saw is bothering you, keep in mind the varying implementations of sawtooth in analog keyboards:

So depending on what you're after "perfect" may not be ... well, perfect.

The shape doesn't bother me I appreciate the Montage for being it's own instrument. Thats one of the reasons I have so many Keyboards, they all have their personalities. I just got the Montage and for some reason i thought the Reface was a scaled back version of the same new architecture.
I am able to get awesome sounds out of both of them anyway so it's all good.

It's interesting that this is missed by so many... the Spectral Form and Spectral Skirt parameters that give the FM-X more flexibility in Waveform creation is seen as a "ding" that it does have a feedback loop per Operator. When understood, the Form and Skirt actually give you more flexibility not less.

We have a tutorial coming up fairly soon, that delves into constructing complex sounds using just simple two Operator (M:C) Modulator:Carrier stacks. This should make clear just how much farther the Form selection, and the Skirt setting can take you when you approach it with purpose. Should be eye opening for many.

The reason for the single Feedback loop is to bring compatibility with legacy FM sounds... but Feedback is accomplished in FM-X by selecting All harmonics or Odd harmonics and increasing the Skirt. Wave shape is identical to reface Feedback... FM-X goes beyond this to include two more Forms with adjustable Skirts and resonant Peaks. (So the infinite sounds capable are more infinite... 🙂

Did that tutorial came out? I am interested for the MODX

An FM-X Exploration Part 1 of 4

Although not necessarily the alluded article - there are other resources for FM-X from Yamaha:

Manny's FM-Xplorations Articles 1-3:

https://yamahasynth.com/montage-category/mannys-fmxplorations-article-1
https://yamahasynth.com/resources/mannys-fmxplorations-article2
https://yamahasynth.com/resources/mannys-fmxplorations-article-3